School Science Lessons
TopicIndexAa-Ac
2019-08-13
Please send comments to: J.Elfick@uq.edu.au

Chemistry Aa-Ac
Table of Contents
A2 Milk:
16.3.1
AAA, Atomic absorption spectroscopy: 27.195
Abbreviations, chemistry: 1.0 (Table 1.0)
Abietic acid, C20H30O2,
Abscisic acid, C15H20O: 9.1.7.5 (Plant growth regulator)
Absolute alcohol, ethanol, ethyl alcohol
Absolute zero, Kelvin scale: 6.3.1.5.03
Absorb impurities on charcoal, test with litmus: 10.1.1
Abundance of elements, Elements in the Earth's crust: 36.3.01
Abundance of elements, Elements in the Sun: 36.3.02
Abuse of volatile substances, inhalants: 11.11.01
Acacetin, C16H12O5
Acanthicifoline, alkaloid
Acaricides: 16.8.16
Accumulator, Motor vehicle lead-acid battery: 32.5.3.0
Acculfame K, potassium compound, atrificial sweetener, E950 Accuracy and error: 3.3.1.0
Acephate (insecticide): 16.4.1
Acesulfame
Acetal: 16.1.3.8
Acetaldehyde, C2H4O, ethanal
Acetamide, CH3CONH2
Acetaminophen, C8H9O2, paracetamol
Acetamiprid, C10H11ClN4, (insecticide)
Acetates, CH3COO-
Acetic acid, CH3COOH, ethanoic acid, in vinegar, E260
Acetic alcohol, Prepare acetic alcohol solution: 3.1
Acetic anhydride (CH3CO)2O
Aceto-alcohol, Prepare aceto-alcohol solution: 4.1
Aceto-carmine, Prepare aceto-carmine, microscopy stain: 3.3.0
Aceto-orcein, Prepare aceto-orcein, microscopy stain: 3.2
Acetoacetic acid, CH3COCH2COOH
Acetochlor, C14H20ClNO2: 16.7.8 (herbicide)
Acetone, CH3COCH3
Acetone peroxide, C9H18O6, TATP: Contact explosives
Acetonitrile, CH3CN
Acetyl, CH3CO-, ethanoyl
Acetyl chloride, CH3COCl
Acetyl eugenol, C12H14O3, eugenol acetate
Acetylacetonate, C5H7O2-
Acetylcholine, C4H16NO2+
Acetylene, C2H2
Acetylides, C22-
Acetyldigoxin, C43H66O15, N-Acetyltyramine
Acetylpyrrolidine, C6H11NO
Acetylpyrroline, cyclic secondary amine
Acetylsalicyclic acid, C9H8O4
Acid, acid-, acids, acidic, acidify, acidity
Acolongifloroside K, C29H44O12
Aconine, alkaloid, C25H41NO9
Aconitine, alkaloid, C34H47NO11
Aristolochic acid
Acridine, C13H9N
Acriflavine, C14H14ClN2
Acrilan (trade name), Polyacrylonitrile : 3.7.5
Acroleic acid, CH2CHCO2H, acrylic acid
Acrolein, CH2=CHCHO
Acryl polymer, CH2=CH-CN
Acrylonitrile, CH2=CH-CN
Acrylamide, C3H5NO: 16.1.5.6.1
Acrylic acid, CH2CHCOOH, propenoic acid
Acrylic glass, Polymethyl methacrylate: 3.7.24
Acrylics: 3.4.2.8.1
ACS Reagent, chemicals standards
Actinides, actinoids: 2.1.0
Actinidine, C10H13N
Actinium, Ac
Actinolite, Hornblende: 35.17.0 (Geology)
Actinolite: 35.14.1 (See 4. Geology)
Activated carbon, activated charcoal (seller information): 11.0
Active constituent: 16.18.4 (pesticides)
Activity series of metals as reducing agents: 12.14.0
Acute toxicity: 5.1 (Safety)
Acyl halide: 16.1.5.5
Acyclic hydrocarbons, alkanes, alkenes, alkynes: 16.4.1.0

Abietic acid, C20H30O2
Abietic acid, C20H30O2, main component of gum rosin, colophony, Greek pitch, on violin bows and ballet shoes
16.3.5.1.4 Diterpenes (C20H32), (four isoprene units)
Gums (See: Gum Rosin).

9.1.7.5 Abscisic acid, C15H20O4
Abscisic acid stimulates: closure of stomates during water stress, seeds to synthesize storage, d5H20O4
Abscisic acid stimulates: closure of stomates during water stress, seeds to synthesize storage, dormancy, responses to wounding, inhibits
shoot growth, effects of gibberellins.

Acesulfame
Acesulfame-K, artificial sweetener
E962 Salt of aspartame-acesulfame (artificial sweeteners, emulsifiers, stabilizers, thickeners and gelling agents) (Health risk, tumours)
E950 Acesulfame-K, C4H4KNO4S (Acesulfame potassium) (synthetic chemical) (artificial sweetener) (Health risk, tumours.)
19.2.11.2 Cola, Diet or Light contents.

Acetaldehyde, C2H4O, ethanal
Prepare ethanal with potassium dichromate: 16.3.2.7
Prepare ethanal with potassium manganate (VII): 16.3.2.6.

Acetamide, CH3CONH2
Acetamide, CH3CONH2, ethanamide, Toxic if ingested
Amide RCONH2 (amine + acid), No prefix
Suffix: -oic, Suffix: -amide, e.g. acetamide = ethanamide, CH3CONH2
Amides: 16.1.5.6
Heat energy changes solid to liquid: 24.10.0
Latent heat of fusion of ice to water: 24.1.5, (See 4.).

Acetates, CH3COO-
Acetates: 16.1.3.6
The suffix "-ate" is for a salt or ester of an acid ending in "-ic", so an acetate is a salt or ester of acetic acid.
Esters RCOOR', Prefix: R-oxycarbonyl-, Suffix: -alkyl, -oate, e.g. methyl formate = methyl ethanoate, HCOOCH3, but "ethyl acetate",
(keeps old name)
Acetic anhydride (CH3CO)2O
Acetic acid, CH3COOH, ethanoic acid
n-amyl acetate
Celluloid: 3.5.7
Cellulose acetate: 3.5.8
Cellulose triacetate: 3.5.8
Chromium (III) acetate, chromium (III) ethanoate, chromic acetate, chromium acetate, Harmful if ingested
Cinnamyl acetate, C11H12O2, CH3CO2CH2CH=CHC6H5, fragrance ingredient, in chewing gum
Ethoxyethanol, C4H10O2
Ethyl ethanoate
Ethyl ethanoate as a salt (CH3COONa): Sodium acetate
Ethyl ethanoate
Ethyl ethanoate as an ester: (CH3COOC2H5) Ethyl ethanoate
Lead (II) acetate, Pb(CH3COO)2, lead (II) ethanoate
Medroxyprogesterone acetate, Depo-Provera: 10.7.9.1
Paris Green, Copper (II) acetoarsenite
Polyvinyl acetate: 3.7.36
Tests for acetates: 12.11.5.1

Acetic anhydride, (CH3CO)2O
Acetic anhydride (CH3CO)2O, ethanoic anhydride, acetic acid anhydride, acetyl oxide, acetic oxide, Strong respiratory irritant
Acetic anhydride, Use < 25 mL or g in a fume cupboard or a well-ventilated area.
Acetic anhydride, Solution < 8%, Not hazardous, i.e. 8% acetic acid
Acetic anhydride (CH3CO)2O, highly volatile liquid, irritating odour because acetic acid forms by reaction with moisture in air,
corrosive to skin, eyes and gut, low toxicity because converts to acetic acid, natural component of the human diet.
Acetic anhydride with water becomes acetic acid by hydrolysis, heat is evolved, but the reaction catalysed by the acetic acid formed
is not dangerous if < 25 mL used.
Prepare acetate esters from alcohols by reaction with acetic anhydride.
Reactions with water hazardous, with alcohols vigorous if acid catalysts present, with boric acid, chromium (VI) oxide, permanganate
salts, nitric acid and metal peroxides may be explosive.

Acetoacetic acid, CH3COCH2COOH
Acetoacetic acid, diacetic acid, keto acid, C4H6O3, CH3COCH2COOH, ketobutyric acid, β-ketobutyric acid,
Ethyl acetoactonate (ethyl 3-oxobutanoate): 16.5.01
Keto acids: 16.3.8.7
Tests for ketones: 19.1.20.4.1.

Acetone, CH3COCH3
Cleaning agents, solvents: 2.20.4
Boiling point of inflammable liquids: 3.6
Bromination of acetone: 12.19.9.7
Solvent extraction of oil from peanuts: 10.12.1
Oxidation of acetone vapour, copper catalyst: 17.3.10
Potassium dichromate as an oxidizing agent: 15.2.3 (See 5.)

Acetone
Acetone, 2-propanone, propanone, dimethyl ketone
Highly flammable, irritant vapour, slightly toxic if ingested
Low cost, technical grade acetone, from hardware store, use as solvent, clean glassware
CH3COCH3, O=C(CH3)2 (2-propanone, dimethyl ketone), Harmful, highly flammable
Acetone ACS reagent, 99.5%
Acetone, CH3COCH3 (CH3)2C=O, dimethyl ketone, 2-propanone, clear colourless volatile liquid, characteristic smell, inflammable,
r.d. 0.79 gm cm-3, B P 56.5oC, miscible with water and ether and oils, sharp sweet taste, characteristic odour, solvent for resins,
primers, plastics, UN CAS No 1090.
Acetone is a curing agent for epoxy resin adhesives, surface coating, irritant.
Use acetone in a fume cupboard or use < 50 mL in a well-ventilated area.
Acetone react violently with chloroform.
Use ethyl acetate or methyl isobutyl ketone as alternative solvent to acetone.
Heat acetone on a water bath, NOT on a naked flame.
Junior secondary students should use acetone only as a cold solvent, and they should NOT react or heat acetone.
Acetone dissolves polystyrene packing pieces rapidly by dissolving the linking units.
Common names: Nail polish remover (not in Australia), e.g. "Cutex", nail paint remover, paint thinner (more acetone per volume),
may be sold as "pure acetone".
Junior secondary students should use acetone only as a cold solvent, and they should NOT react or heat acetone.
Acetone dissolves polystyrene packing pieces rapidly by dissolving the linking units.
Common names: Nail polish remover (not in Australia), e.g. "Cutex", paint remover, paint thinner (more acetone per volume), may be
sold as "pure acetone".

Acetonitrile, CH3CN
Acetonitrile, CH3CN, cyanomethane, methyl cyanide, flammable colourless liquid, sweet ether-like odour
See diagram: Acetonitrile
Acetonitrile, CH3CN, simplest organic nitrile, Toxic if ingested
Acetonitrile (acetonitrilo), CH3CN, monodentate ligand
Acetonitrile, Solution < 3%, Not hazardous
Acronitrile, C3H3N, acrylics (plastics), vinyl cyanide, cyanoethylene, 2-propenenitrile, Toxic, Highly flammable
Acronitrile, colourless to pale yellow liquid, pyridine-like odour, evaporates rapidly, in synthetics, paint
Indole-3-acetonitrile C10H8N2.

Acetyl chloride, CH3COCl
Acetyl chloride, CH3COCl, ethanoyl chloride, acyl chloride, (low flash point, below 32oC), Toxic by all routes
Chlorine compounds: ethanoyls (-COCl) (-oyl chloride), ethanoyl chloride (acetyl chloride) (CH3COCl)
Acyl halide, acid chloride, Acid chlorides group: (-COCL), Suffix: -oyl chloride
acyl chloride (RCOCl), e.g. ethanoyl chloride (acetyl chloride) (CH3COCl).

Acetylacetonate, C5H7O2-
Acetylacetonate, C5H7O2- (Acac), CH3-C(O)-CH-C(O)-CH3, bidentate ligand
Beryllium acetylacetonate, Be(C5H7O2)2, Cadmium acetylacetonate, C10H16CdO4, Cobalt (III) acetylacetonate, CO(C5H7O2)3
Gallium (III) acetylacetonate, C15H21GaO6 , Indium (III) acetylacetonate, C15H21InO6, Iridium (III) acetylacetonate, C15H21IrO6
Iron (III) acetylacetonate, C15H21FeO6m, Iron (III) trifluoroacetylacetonate, C15H12F9FeO6, Lead (II) acetylacetonate, Pb(C5H7O2)2
Manganese (III) acetylacetonate Mn(C5H7O2)3, Terbium (III) acetylacetonate hydrate, C15H21O6Tb.xH2O.

Acetylcholine, C4H16NO2+
Acetylcholine (Ach), C7NH16O+, neurotransmitter stimulates muscle, acetyl ester of choline, cholinergic receptor agonist, major
transmitter at neuromuscular junctions
Atropine, C17H23NO3, alkaloid
Nicotine, C10H14N2
Nicotine, C10H14N2, tobacco smoking and chewing: 11.11.16 (See: 7.)
Fruit & seed, Breadfruit: 9.0 (See: 4.)

Acetylpyrrolidine, C6H11NO
1-Acetylpyrrolidine, N-Acetylpyrrolidine, [1-(pyrrolidin-1-yl)ethanone], 2-acetyl-1-pyrrolidine, [1-(Pyridin-2-yl)ethan-1-one], ketone, substituted pyrrolidine, CH3COC5H4N,
in malt, popcorn, beer

Acetyl pyrroline, C6H9NO, Cyclic Imine
2-acetyl-1-pyrroline (2AP), substituted pyrroline, cyclic imine, ketone, ethanone, white bread smell,
in cereals and cereal products, hot popcorn smell, jasmati and basmati rice smell, wheat bread crust, sweet corn, roasted sesami,
in Screwpine.

Acid, acid-, acids, acidic, acidify, acidity
See: Acids & Bases (Commercial)
Acids: 12.3.0
Acid-base indicators
Acid anhydrides: 16.1.5.7
Acid fuchsin, Andrade's acid fuchsin: 1.0, (indicator)
Acid rain
Acidic oxide
Acidity, [degree of being an acid]
Acid-base indicators: 1.0
Acidity and alkalinity: 18.1.0.1
Acidity of vinegar: 12.8.4.3
Acidity regulators, food additives: 19.4.8
Acids and metals or insoluble bases, prepare salts: M2
Acids and salts, prepare salts: M6
Acids with, action of acids with other substances
Acidity, See: Refractometers Testing Acidity, (Commercial)
Acidity test, Milk testing and quality control: 16.1.5
Acidulated water, [cooking]: 19.1.0.6
Alkalinity, total alkalinity and buffer capacity: 18.7.9
Carbonic acid, soda water: 3.34.3a
Hydrochloric acid
Lead-acid battery, Motor vehicle battery: 32.7.0
Prepare acid-base indicators: 37.0
Prepare acids and bases: 7.0
Prepare acids, dilute acids and bases (Safety instructions): 3.4.3
Prepare acids, dilute acids: 5.3.1
Phosphoric acid
Reactions of dilute acids: 12.3.1
Soil acidity, pH: 6.17.2
Sulfuric acid: 12.18.5
Titration, acid-base neutralization: 12.11.2.0
Tests for acid radicals in solution: 12.11.5.0
Tests for acids and bases: 1.0.0.

An acid is a good electrolyte, reacts with active metals, turns blue litmus red and has a sour taste.
(Latin: acidus, sour tasting)
Acids contain hydrogen replaceable by metals.
Acids neutralize alkalis and alkalis neutralize acids.
Acids are sour corrosive, mainly liquids, that can dissolve metals.
Acids with water produce hydrogen ions, H+.
An acid is a proton donor (H+) (Bronsted-Lowry definition).
Acids an donate protons or accept pairs of electrons.
The "acid test" was originally the nitric acid test for gold because only gold would not dissolve in it.
To acidify is to add acid to usually a solution.
Acidic substance have pH < 7.
An acid salt is formed by an acid where incomplete exchange of replaceable hydrogen occurs.
An acid dye is a dye that is a metallic salt of an acid and can be applied in an acid medium.

Acid rain
Acid rain, fuel pollutants and effects
Acid rain is rain made acidic by atmospheric pollution.
Acid rain and nitrogen oxides, NOx: 3.48
Acid rain, SOx, from burning sulfur or sulfur compounds: 12.6.0.1
Air pollution: 18.6.0
CFCs, chlorofluorocarbons, "Freons": 12.19.5.0

Acidic oxides
Carbon dioxide, acidic oxides (non-metal oxides): 12.17.3
Carbon dioxide with barium hydroxide solution: 12.17.3.2
Carbon dioxide with sodium hydroxide solution: 12.17.3.1
Dilute acids with acidic oxides (non-metal oxides): 12.3.8
Reactions of oxides: 12.17.0.

An acidic oxide is the oxide of a nonmetal, e.g. carbon dioxide, CO2, or a metal in a high oxidation state, e.g. chromium trioxide, CrO3.
Acidic oxides do not react with acids.
Acidic oxides form when a nonmetal burns
Acidic oxides are usually gases at room temperature, e.g. CO2, NO2, SO2, SO3.
Acidic oxide + base --> salt + water
CO2 (g) + NaOH (aq) --> Na2CO3 (s) + H2O (l)
Acidic anhydride is an acidic oxide which reacts with water to form a base.
CO2 + H2O --> H2CO3 (carbonic acid)
SO3 (g) + H2O --> H2SO4 (aq) (sulfuric acid.

Acids with, action of acids with other substances
Acids with baking soda: 12.1.18
Acids with sodium carbonate: 12.1.25
Acids with sodium thiosulfate: 12.1.40
Aluminium with acids: 12.1.1
Ammonium carbonate with acids: 12.12.3
Concentrated acids with metals, nitric acid with copper: 12.3.12
Concentrated acids with a non-metal, carbon: 12.3.14
Dilute acids with acidic oxides (non-metal oxides): 12.3.8
Dilute acids with amphoteric oxides: 12.3.5.1
Dilute acids with basic oxides, metal oxides, copper (II) oxide: 12.3.5
Dilute acids with calcium hydrogen carbonate: 12.3.10.1
Dilute acids with carbonates, common carbonates: 12.3.9.0
Dilute acids with hydroxides, magnesium hydroxide: 12.3.6
Dilute acids with hydroxides, sodium hydroxide: 12.3.7
Dilute acids with metals: 12.10.2.1
Dilute acids with metals, hydrochloric acid: 12.3.2
Dilute acids with metals, sulfuric acid, hydrochloric acid, ethanoic acid: 12.3.2.1
Dilute acids with metals, sulfuric acid with steel wool: 12.3.3
Dilute acids with non-metals, carbon, sulfur: 12.3.4
Dilute acids with salts: 12.3.15
Dilute acids with sodium hydrogen carbonate: 12.3.10
Dilute acids with sodium hydroxide: 12.3.7.1
Dilute hydrochloric acid with hydroxides: 12.3.7.2
Dilute hydrochloric acid with sodium carbonate: 12.3.9.2
Dilute nitric acid with copper: 12.3.11.0
Dilute sulfuric acid with aluminium: 12.3.3.1
Dilute sulfuric acid with calcium carbonate: 12.3.9.6
Dilute tartaric acid with egg shell, soil, wood ash: 12.3.9.4
Dilute tartaric acid with sodium carbonate: 12.3.9.3
Dilute sulfuric acid with steel wool: 12.3.3
Dilute hydrochloric acid with calcium carbonate: 12.3.9.1
Dilute hydrochloric acid with sodium carbonate: 12.3.9.2
Metals displace hydrogen from acids: 3.74
Microscale titration, sodium hydroxide with dilute acids: 12.8.7
Sulfuric acid with copper: 12.3.13
Titration of acids with bases: 3.78.

Acridine, C13H9N
See diagram 16.3.4.0: Acridine, anthracene, anthroquinone, cinnoline, naphthalene, naphthol, quinoline
Acridine, C13H9N, Toxic if ingested and skin contact
First aid if ingested - Give water.
Induce vomiting.
Acridine derivatives (alkaloids): 16.3.8
Acridine Orange (basic) (CI. 46005),
Acridine Orange (CI.22657), 3, 6-dimethylaminoacridine, stains nucleic acid
Acriflavine, C14H14ClN2, orange-brown, dye and antiseptic, derived from acridine.

Acroleic acid, CH2CHCO2H
Acroleic acid, CH2CHCO2H, C3H4O2, acrylic acid, propenoic acid, prop-2-enoic acid, Toxic by all routes
Acroleic acid is the simplest unsaturated carboxylic acid.
Acroleic acid, Solution < 5%, Not hazardous,
Corrosive, colourless liquid with an acrid odour
In polishes, paints, coatings, rug backings, adhesives, plastics, textiles, and paper.
Polyacrylic acid, cross-linked sodium salt
Polyacrylic acid, water-soluble polyelectrolyte, increase building substances viscosity
Polyacrylamide powder, superabsorbent, "Instant Wet Expanding Snow"
Prepare sodium polyacrylate gels (ghost crystals): 3.4.2.5.1
Poly (acrylic acid), PAA, carbomer (C3H4O2)n, monomer
Sodium polyacrylateis sold as "Super Expanding Creatures".

Acrolein, C3H4O
12.7.4 Tests for glycerine
Acrolein, C3H4O, CH2=CHCHO, prop-2-enal, ethylene aldehyde, acrylic aldehyde, aqualin, Magnacid, Toxic by all routes
Acrolein, Solution < 0.1%, Not hazardous, clear, yellowish liquid, sweet, pungent burnt fat smell, highly flammable, volatile organic
compound,
Unstable, polymerizes in the presence of light or alkali or strong acids, in cigarette smoke and vehicle exhaust, aquatic herbicide, kills
algae and waterweeds.

Acrylic acid, CH2CHCOOH
Acrylic acid, "acrylics": 3.4.2.8.1
Acrolein test for presence of fats, heat sample with potassium bisulfate, --> acrolein released
Butter, butter oil, clarified butter, ghee: 16.2.3 (See: 6.)
Heat different foods: 9.128
Tests for glycerine: 12.7.4
Tests for glycerol: 12.12.3.

Acrylonitrile, CH2=CH-CN,
Acrylonitrile, flammable organic chemical with low flashpoint, below 32oC, poison, used to manufacture acrylic acid
Acryl polymer, generic name for fibres > 85% acrylonitrile units
ABS mixed polymer, acrylonitrile, butadiene, styrene, thermoset plastics: 3.7.28
Acrylonitrile-butadiene-styrene, burning test for synthetic fibres: 4.3.1
Chemical sources of polymer material: 3.4.02
Nitriles: 16.2.4.2
Polyacrylonitrile, burning test for synthetic fibres: 4.3.11.

Actinium, Ac
Actinium
, Table of Elements
Actinium, Ac (Greek actin ray), refers to light causing chemical change, radioactive, occurs in pitchblende.

12.3.0 Acids, properties of acids
Acids are good electrolytes, react with active metals, turn blue litmus red, and have a sour taste.
Dilute acids contain hydrogen ions in aqueous solution.
You can represent the hydrogen ion, which is really a proton, in different ways to show how it is related to the water molecules in the
solution.
You can show it as the hydrated hydrogen ion, [proton, H+ (aq)] or as the hydronium ion [oxonium ion, H3O+ (aq)] but, for
convenience, use H+ (aq).
Concentrated sulfuric acid exists mainly as H2SO4 molecules.
Hydrochloric acid and nitric acid dissociate into ions even in concentrated solution.
Weak acids, e.g. ethanoic acid (acetic acid, CH3COOH) carbonic acid and sulfurous acid dissociate very little in aqueous solution,
but their salts, e.g. potassium acetate (CH3COOK) are completely dissociated into ions.
Using the Bronsted-Lowry definition of acids and bases an acid donates a proton (H+) to another substance and a base accepts a
proton from another substance.
When sulfuric acid dissociates in water it donates a proton (H+) to the water molecule.
So in this reaction the water molecule acts as a base.
H2SO4 + H2O --> HSO4- + H3O+
When ammonia dissolves in water, ammonia accepts a proton and so it is the base.
So in this reaction the water molecule acts as an acid.
NH3 + H2O <--> NH4+ + OH-.

12.3.0.1 Amphoteric substances
Amphoteric substances can act as an acid or a base.
In the above reactions water is acting as a base with sulfuric acid and is acting as an acid with ammonia.
Similarly, bicarbonate ion can act as an acid to donate a proton to form carbonate ion:
HCO3- + H2O <--> CO32- + H3O+
Also, bicarbonate ion can act as a base to accept a proton to form carbonic acid:
HCO3- + H2O <--> H2CO3 + OH-.

12.3.0.2 Polyprotic acids
Polyprotic acids can donate more than one proton, e.g. carbonic acid.
H2CO3 + H2O <--> HCO3- + H3O+ (The first proton to be donated to a water molecule.)
HCO3- + H2O <--> CO32- + H3O+ (The second proton to be donated to a water molecule.)

Quinacrine, C23H30ClN3O
Quinacrine, C23H30ClN3O, Mepacrine, Atabrine
Acridine derivative, bright yellow powder, odourless, can be toxic, kills protozoa, antihelminthic, used to treat giardiasis
During World War II in the pacific region widely used as antimalarial drug known widely as Atebrine, but unpopular with Australian
troops fighting in Papua New Guinea because it turned skin yellow and was supposed to make men infertile.
Atebrine was generally replaced by chloroquine, C18H26ClN3, but Plasmodium falciparum has developed resistance to it.

12.3.0.3 Strong acids and weak acids, Ka, pKa
A strong acid completely dissociates into ions, e.g. nitric acid has almost complete dissociation, 93%
HNO3 (aq) + H2O --> H3O+ (aq) + NO3- (aq)
A weak acid only partly dissociates into ions, e.g. acetic acid.
CH3COOH + H2O <--> CH3COO- + H3O+
So describing acids and bases as strong or weak only refers to their reaction with water and has nothing to do with concentration or
the number of moles in a volume.
The strong acids are perchloric acid (HClO4), hydrochloric acid (HCl), hydrobromic acid (HBr), hydroiodic acid (hydriodic acid),
(HI), nitric acid (HNO3), and sulfuric acid (H2SO4).
Any other acid is a weak acid because it does not completely dissociate in water.

12.3.0.3a Acid dissociation constant, Ka
The acid dissociation constant, Ka of the acid HB:
HB (aq) <--> H+ (aq) + B- (aq)
Ka = [H+][B-] / [HB]
Ka is a measure of the degree to which an acid or base will dissociate in water.
Stronger acids have a larger Ka and a smaller pKa than weaker acids.
The greater the value of Ka, the more the formation of H+ is favoured, and the lower the pH of the solution.

12.3.0.3b Acid dissociation constant at logarithmic scale, pKa
pKa = -log10Ka
Strong acids have pKa value < −2
When the pH of solution is at the value of pKa for a dissolved acid, that acid will be 50% dissociated.
Sulfuric acid, H2SO4 --> HSO4-, pKa -10
Hydroiodic acid, HI,
HI (g) + H2O (l) --> H3O+ (aq) + I- (aq), pKa -9
Hydrobromic acid, HBr
HBr (g) + H2O (l) --> H3O+ (aq) + Br- (aq), pKa -8
Perchloric acid, HClO4
HClO4 + H2O --> H3O+ + ClO4- , pKa -10
Hydrochloric acid, HCl,
HCl (g) + H2O (l) --> H3O+ (aq) + Cl- (aq), pKa -7
Hydronium ion, H3O+
H2O + H2O <--> H3O+ + OH-, pKa -1.74
Nitric acid, HNO3
HNO3 + H2O --> H3O+ + NO3-, pKa - 1.3
Chloric acid, HClO3, pKa -1.0
Weak acid has pKa value −2 to 12 in water
Acetic acid, CH3COOH, pKa 4.75.

12.3.0.4 pH
Water can transfer a proton from one molecule to another, autionization.
2H2O <--> H3O+ + OH-
and
H2O <--> H+ + OH-
The product of hydrogen ion concentration, [H+] and hydroxide ion concentration, [OH-] = the constant, Kw
Kw = [H+] × [OH-] = 1.00 × 10-14
So [H+] = 10-7 and [OH-] = 10-7
The hydrogen ion concentration is very small in pure water so the concentration is describes in terms of its negative log.
pH is the negative log of the hydrogen ion concentration, pH = -log[H+], so hydrogen ion concentration, [H+] = 10-pH.
So acidic solutions have a high [H+] and low pH values .
Basic solutions have low [H+] and high pH values.
A solution that is neither acidic nor basic, a neutral solution, has [H+] = [OH-], so pH = 7.
A more acid solution has pH approaching 1.
A more basic solution has pH approaching 14.

12.3.0.5 Ionization reaction of carbonic acid
H2O (l) <--> H+ (aq) + OH- (aq)
2H+ (aq) + CO32- (aq) <--> H2CO3 (aq) carbonic acid
CO2 + H2O <--> H3O+ + HCO3-, K1 = 4.4 × 10-7
HCO3- + H2O <--> H3O+ + CO32-, Ka = 4.7 × 10-11.

12.3.1 Taste of acids, solid acids in the home
BE CAREFUL! NEVER TASTE ACIDS IN THE LABORATORY!
Citric acid, C6H8O7
Acetic acid, glacial, CH3COOH, ethanoic acid, vinegar
Do NOT taste these acids in the laboratory.
Each acid has a sour taste that is a characteristic of acids.
Lemon juice contains the white crystalline citric acid.
Vinegar contains ethanoic acid (acetic acid, CH3COOH).
Moisten your finger with a very dilute solution of hydrochloric acid.
Rub your fingers together and then lick them.
Repeat the procedure with very dilute solutions of acetic acid and citric acid.
Do not taste any other acids because they may damage living tissues.

12.3.2 Dilute acids with metals, hydrochloric acid
Reactions of acids with metals are exothermic.
The higher the metal is in the reactivity series the greater the heat liberated.
Dilute hydrochloric acid with zinc:
Zn (s) + 2HCl (l) --> H2 (g) + ZnCl2 (aq)
The order of activity of metals with acids is similar to the order of activity with water.
Evolution of hydrogen occurs
Table 12.3.2


1. Use different cleaned metals, e.g. calcium pieces, iron nail, lead sinker, magnesium ribbon, copper wire, aluminium sheet and zinc granules.
Rub them with emery paper to make surfaces clean of oxides.
Put each metal into a separate test-tube.
Add 10 mL of 2 M hydrochloric acid to test-tubes.
Observe the properties of any gas liberated and name it.
Test it with moist pieces of red and of blue litmus paper, with a drop of lime water hanging from a glass rod and with a lighted splint.
Compare the rate at which hydrogen gas evolves by noting the rate and size of the hydrogen gas bubbles from the reaction.
Describe the rate of reaction as nil, very slow, slow, moderately fast, very fast, and whether energy, in the form of heat, is produced
(exothermic) or absorbed (endothermic).
List the acids in order of their activity towards metals and state whether the same gas was liberated during each reaction and whether
a salt may be isolated when the acids react with a metal.

2. Make up a reactivity series by listing the elements in approximate order of their activity with respect to acids, from the most active
to the least active.
Compare the results with the table of the reactivity series of some metals.
The order of activity of the metals used, from the most active to the least active, is: magnesium, aluminium, zinc, iron with lead and
copper displaying no noticeable reaction.
When reaction did occur, the gas liberated was hydrogen gas.
The reactions of these acids with metals are exothermic.
The order of activity of the acids is that dilute hydrochloric and dilute sulfuric acids are about equal in activity but that they are more
reactive than acetic acid.
The order of activity of the metals with respect to acids is similar to that with respect to water.
Magnesium ribbon forms most rapid bubbles of hydrogen gas then zinc then iron.
Tin forms few bubbles of hydrogen gas.
Copper forms no bubbles of hydrogen gas.
Lead forms some lead chloride precipitate on the surface of the lead.
Aluminium develops a layer of aluminium oxide that obstructs further chemical reactions.

3. Note the properties of any gas that forms.
Test the gas with moist litmus paper a lighted splint and a hanging drop of lime water on a glass rod.

4. Feel the test-tube to note whether heat energy is released or absorbed.
The reactions of these acids with metals are exothermic.

5. List the elements in approximate order of their activity with respect to hydrochloric acid from the most active to the least active.
The order of activity is: magnesium, aluminium, zinc, iron, lead (no noticeable reaction), copper (no noticeable reaction).

12.3.2.1 Dilute acids with metals, sulfuric acid, hydrochloric acid, ethanoic acid
Dilute hydrochloric and dilute sulfuric acids are about equal in activity, but that they are more reactive than ethanoic acid (acetic acid).
Note the slower production of hydrogen gas with the weak acetic acid.
The reaction with sulfuric acid forms insoluble sulfates on the surface of calcium and lead that obstructs or stops reactions.
List the acids in order of their activity on metals.
2CH3COOH (aq) + Mg (s) --> Mg(CH3COO)2 (aq) + H2 (g)
ethanoic acid + magnesium --> magnesium ethanoate + hydrogen

12.3.3 Dilute sulfuric acid with steel wool
Add dilute sulfuric acid to steel wool in a test-tube.
Test the gas that forms with a lighted taper.
BE CAREFUL! THE GAS IS HYDROGEN GAS!
Heat the mixture in a beaker of hot water until all the steel wool has dissolved.
Add more acid when necessary.
Filter the hot solution then leave it to cool.
Crystals form on cooling.
If no crystals form, add alcohol because the salt is less soluble in it.
Dry the green crystals of iron (II) sulfate-7-water between absorbent paper.
Fe (s) + H2SO4 (aq) --> H2 (g) + FeSO4 (aq).

12.3.3.1 Dilute sulfuric acid with aluminium
Heat dilute sulfuric acid with pieces of aluminium foil in a test-tube.
Some effervescence occurs but sometimes not enough to test for hydrogen gas with a lighted taper.
After heating for 5 minutes, decant the solution that contains aluminium sulfate into another test-tube and add ammonia solution.
A white jelly-like precipitate of aluminium hydroxide forms.

12.3.3.2 Magnesium with sodium hydrogen sulfate
Add 3 cm of magnesium ribbon to 3 cm of sodium hydrogen sulfate solution in a test-tube.
The metal reacts with the sulfuric acid in the solution.
Describe what you see.
Tests for hydrogen gas.
Remove any magnesium that has not reacted from the solution, pour part of the liquid into an evaporating basin and leave for
magnesium sulfate crystals to form.

12.3.3.3 Iron with sodium hydrogen sulfate
Add a finger width of iron filings to a finger width of sodium hydrogen sulfate solution in a test-tube.
Heat the mixture to speed up the reaction.
The metal reacts with the sulfuric acid in the solution.
Describe what you see.
Tests for hydrogen gas.
Leave to stand until all bubbles have ceased to appear.
Pour part of the liquid into an evaporating basin and leave for magnesium sulfate crystals to form.
Test the liquid with universal indicator paper.
(The indicator changes colour to red, orange, or yellow for acids and green, or violet for alkalis.)
Pale green is the colour for neutral substances.
Before testing, make the paper this colour by dipping it into neutral tap water for a few moments.
The Universal indicator turns yellow indicating the presence of an acid.
Filter the liquid, and pour part of the clear solution into the evaporating basin and leave for pale green crystals of iron sulfate to form
(FeSO4.7H2O), green vitriol.
A solution of a salt is not necessarily neutral because some salts, like iron sulfate, form acids when dissolved in water.

12.3.4 Dilute acids with non-metals, carbon, sulfur
Add a piece carbon and sulfur to dilute hydrochloric acid, dilute sulfuric acid and dilute ethanoic acid (acetic acid) in separate test-tubes
Heat the test-tubes.
No reaction occurs.
Non-metals do not react with dilute acids.

12.3.5 Dilute acids with basic oxides, metal oxides, copper (II) oxide
1. Heated dilute acids react with metal oxides to form a salt and water:
Pour dilute sulfuric acid into a Pyrex test-tube and heat in a beaker of boiling water until the sulfuric acid is nearly boiling.
BE CAREFUL!
Add pieces of copper (II) oxide one by one while stirring until some remains unreacted with the acid.
Filter the undissolved copper oxide from the hot solution.
Leave the filtrate in a watch glass to cool and form crystals.
Blue crystals of copper (II) sulfate-5-water form with water.
Remove the crystals and dry them by pressing between absorbent paper.
H2SO4 (aq) + CuO (s) --> CuSO4 (aq) + H2O (l)
acid + basic oxide ---> salt + water
2. Repeat the experiment with dilute nitric acid.
2HNO3 (aq) + CuO (s) --> Cu(NO3)2 (aq) + H2O (l).

12.3.5.1 Dilute acids with amphoteric oxides
Oxides of Sn, Al, Zn, Pb, and Sb are amphoteric.
Amphoteric oxides react with bases to form a salt + water.
Amphoteric oxides react with acids to form a salt + water.
Add dilute hydrochloric acid to zinc oxide.
2HCl (aq) + ZnO (s) --> ZnCl2 (aq) + H2O (l)
2NaOH (aq) + ZnO (s) --> Na2ZnO2 (aq) + H2O (l).

12.3.5.01 Copper oxide with sodium hydrogen sulfate
Add half a test-tube of sodium hydrogen sulfate solution to copper oxide in a test-tube.
Heat the solution slowly until it turns blue.
Be careful of spurting from the test-tube.
Some copper oxide may remain after the reaction.
Filter the solution obtain the filtrate of copper sulfate solution.

12.3.6 Dilute acids with hydroxides, magnesium hydroxide
Basic hydroxides are insoluble in water and react with acids to form a salt and water.
Many metallic hydroxides react with acids to form a salt and water.
Add magnesium hydroxide to dilute sulfuric acid until the reaction stops.
Filter the mixture.
Test the filtrate with litmus paper.
Evaporate the filtrate to dryness so that crystals form.
Mg(OH)2 (s) + H2SO4 (aq) --> MgSO4 (aq) + H2O (l).

12.3.7 Dilute acids with hydroxides, sodium hydroxide
Acids react with (neutralize) alkalis to form a salt and water.
Pour 5 mL of dilute sodium hydroxide solution into a watch glass.
Test with litmus paper.
Red litmus turns blue.
Add dilute hydrochloric acid drop by drop.
Stir as each drop is added.
Test the mixture with the litmus paper until the litmus paper is neither red nor blue, but between these colours.
Evaporate the solution to dryness by heating the watch glass over a beaker of boiling water.
Crystals of sodium chloride (common salt) form.

12.3.7.1 Dilute acids with sodium hydroxide
Repeat the previous experiment with: dilute sulfuric acid, dilute nitric acid, ethanoic acid (acetic acid).
HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
hydrochloric acid + sodium hydroxide --> sodium chloride + water.

12.3.7.2 Dilute hydrochloric acid with hydroxides
[NH3 (aq) is used because while "NH4+" ions and "OH-" ions can be detected, "NH4OH" cannot be detected, so ammonia solution is
shown as "NH3 (aq) + H2O (l)"]
Repeat the experiment with dilute solutions of: potassium hydroxide, calcium hydroxide, aqueous ammonia solution.
acid + (base) alkali --> salt + water
HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
HNO3 (aq) + NaOH (aq) --> NaNO3 (aq) + H2O (l)
HCl (aq) + KOH (aq) --> KCl (aq) + H2O (l)
HCl (aq) + NH3 (aq) + H2O (l) --> NH4Cl (aq) + H2O (l).

12.3.8 Dilute acids with acidic oxides (non-metal oxides)
BE CAREFUL! DO THIS EXPERIMENT IN A FUME CUPBOARD.
Note any reaction for five minutes then evaporate to dryness.
In each case, no reaction occurs.
In each experiment there is no precipitate.
If you evaporate a sample of a remaining solution to dryness in a fume cupboard, no residue remains.
Pass carbon dioxide through hydrochloric acid or ethanoic acid (acetic acid) solution.
Pass sulfur dioxide through hydrochloric acid or ethanoic acid (acetic acid) solution.

12.3.9.0 Dilute acids with carbonates, common carbonates
Dilute acids react with metal carbonates to form a salt, carbon dioxide and water.
Geologists use this reaction to identify calcium carbonate in rock.
Drops of hydrochloric acid cause bubbles to form.

1. Make a chemical egg peeler.
Put an egg in vinegar (contains acetic acid, ethanoic acid).
Note the bubbles forming on the outside of the egg.
Leave overnight then, the next day, pick up the egg with your fingers. The egg has become soft.
Leave to stand for a few days and the egg shell disappears completely.
You can now see through the raw egg.
acetic acid in the vinegar + calcium carbonate in the egg shell --> calcium acetate in solution + bubbles of carbon dioxide + water.

2. Add 5 mL vinegar or dilute hydrochloric acid or dilute sulfuric or dilute nitric acid to pea size amounts of finely divided common
carbonates: sodium hydrogen carbonate, sodium carbonate, calcium carbonate, magnesium carbonate, nickel carbonate, limestone,
lime, oyster shells, egg shell, snail shell, coral.
Continue to add the solid until no further reaction occurs.
Filter and evaporate the filtrate to dryness.
Note any visible changes.
Test any gas liberated by inserting in the mouth of the tube first damp pieces of red and of blue litmus paper then a drop of lime water
hanging on the tip of a glass rod and finally a burning splinter.
In each case the gas is carbon dioxide.

12.3.9.1 Dilute hydrochloric acid with calcium carbonate
See diagram 9.154: Lime water test for carbon dioxide in the breath
1. Put calcium carbonate in a test-tube.
Add 2 mL 1.0 M hydrochloric acid.
Tilt the test-tube so that its mouth is touching a second test-tube containing 5 mL of lime water.
The surface of the lime water turns milky.
Shake the test-tube containing the lime water.
The milky colour on the surface disappears.
CaCO3 (s) + 2HCl (aq) --> CO2 (g) + CaCl2 (aq) + H2O (l)
carbonate + acid --> carbon dioxide + salt + water.

2. Put 5 g of marble chips (calcium carbonate) and the same quantity of dilute hydrochloric acid in a test-tube fitted with a one-hole
stopper and delivery tube.
With the end of the delivery tube dipping into a second test-tube of lime water add water to the first test-tube and quickly replace the
stopper.
The lime water turns milky.
The acid reacts with calcium carbonate to form a salt, carbon dioxide, and water.
hydrochloric acid + calcium carbonate --> calcium chloride + carbon dioxide + water.

12.3.9.2 Dilute hydrochloric acid with sodium carbonate
1. Put sodium carbonate in a test-tube and add drops of dilute hydrochloric acid.
Test any gases formed from the reaction with moist litmus paper, a lighted splint, and a drop of lime water on a glass rod.
The reaction forms carbon dioxide.
Add more carbonate until no more reaction occurs.
Filter and evaporate the filtrate to dryness.
Repeat the experiment with dilute nitric acid.
Repeat the experiment with magnesium carbonate.
Na2CO3 (s) + 2HCl (aq) --> 2NaCl (aq) + H2O (l) + CO2 (g)
Na2CO3 (s) + 2HNO3 (aq) --> 2NaNO3 (aq) + H2O (l) + CO2 (g).

2. Sodium carbonate with hydrochloric acid
Stage 1. Na2CO3 + HCl ---> NaHCO3 + NaCl
Stage 2. NaHCO3 + HCl ---> NaCl + H2O + CO2
Overall equation: Na2CO3 + 2HCl ---> 2NaCl + H2O + CO2
Net ionic equation: CO32- + 2H+ --> H2O + CO2.

3. Shake different solid acids in separate test-tubes half filled with water.
Divide the solutions in the test-tubes into three different test-tubes:
Test-tube A: Add small pieces of red and of blue litmus paper.
Test-tube B: Add three drops of methyl orange solution.
Test-tube C: Add three drops of phenolphthalein solution.
Observe any changes in the solutions.
Add solid sodium carbonate to each acid solution.
Observe any changes in the solutions.
Pass some gas given off into a test-tube containing lime water.
Shake the test-tube for thorough mixing.
Note how milky the solution is because carbon dioxide was produced when the acids reacted with sodium carbonate.

12.3.9.3 Dilute tartaric acid with sodium carbonate
Put 5 g of sodium carbonate and the same quantity of tartaric acid in a test-tube fitted with a one-hole stopper and delivery tube.
With the end of the delivery tube dipping into a second test-tube of lime water add water to the first test-tube and quickly replace the
stopper.
The lime water turns milky.
The acid reacts with sodium carbonate to form a salt, carbon dioxide, and water.
tartaric acid + sodium carbonate --> sodium tartrate + carbon dioxide + water.

12.3.9.4 Dilute tartaric acid with egg shell, soil, wood ash
Many common substances, such as mortar, egg shell, most soils, contain calcium carbonate and wood ashes contain potassium carbonate.
Observe the action of tartaric acid on these substances in a test-tube.
Tests for carbon dioxide by holding a drop of lime water, at the end of a glass tube, in the mouth of the test-tube.

12.3.9.6 Dilute sulfuric acid with calcium carbonate
Put 5 g of marble chips (calcium carbonate) and the same quantity of dilute sulfuric acid in a test-tube fitted with a one-hole stopper
and delivery tube.
With the end of the delivery tube dipping into a second test-tube of lime water add water to the first test-tube and quickly replace the
stopper.
The lime water turns milky.
The acid reacts with calcium carbonate to form a salt, carbon dioxide, and water.
The reaction of sulfuric acid with calcium carbonate proceeds only for a few moments because the salt formed, calcium sulfate, is only
slightly soluble and deposits on the carbonate, preventing this compound from reacting with the acid.
So the reaction with hydrochloric acid above is much better.
sulfuric acid + calcium carbonate --> calcium sulfate + carbon dioxide + water.

12.3.10 Dilute acids with sodium hydrogen carbonate
See 3.34.6: Soda-acid fire extinguisher
The only stable hydrogen carbonates are KHCO3 and NaHCO3.
Sodium hydrogen carbonate, bicarbonate of soda, is used in baking soda, baking powder, self raising flour, effervescent fruit salts,
e.g. Alka-Seltzer, and soda acid fire extinguishers and used to treat acid burns.
Some people swallow sodium hydrogen carbonate to counteract excess acid in the stomach but using magnesium oxide or magnesium
hydroxide that does not react with acids to produce carbon dioxide is better.

1. Add sodium hydrogen carbonate, or other hydrogen carbonates, to acids to form carbon dioxide, water and a salt.
NaHCO3 + HCl --> CO2 + H2O + NaCl
hydrogen carbonate + acid --> carbon dioxide + water + salt.

2. Mix vinegar with bicarbonate of soda in a glass jar.
Drop some naphthalene mothballs into the solution.
The carbon dioxide formed by the reaction of the vinegar (acetic acid) with the sodium hydrogen carbonate forms bubbles of carbon
dioxide on the mothballs in the bottom of the jars.
The mothballs rise to the surface, lose the bubbles and sink again.
NaHCO3 + CH3COOH --> CH3COONa + H2O + CO2 (g).

12.3.10.1 Dilute acids with calcium hydrogen carbonate:
Put powdered calcium carbonate into a test-tube containing about 10 mL of water.
Bubble carbon dioxide through the suspension until no further change takes place.
Soluble calcium hydrogen carbonate forms.
Boil the mixture for 10 minutes.
Add acids to form carbon dioxide, water and a salt.

12.3.11.0 Dilute nitric acid with copper
Very dilute nitric acid may react with very active metals, e.g. magnesium to form hydrogen gas.
When nitric acid reacts with most metals, it oxidizes the hydrogen to water.
Add drops of dilute nitric acid to copper.
Nitrogen monoxide forms, which immediately reacts with oxygen gas in the air to form nitrogen dioxide.
3Cu (s) + 8HNO3 (aq) --> 3Cu(NO3)2 (aq) + 4H2O (l) + 2NO (g)
2NO (g) + O2 (g) --> 2NO2 (g).

12.3.11.1 Nitric acid with metals
Add slowly small pieces of copper, magnesium and zinc to small amounts of dilute nitric acid in separate test-tubes.
If no change is taking place, gently heat the mixture.
Repeat the procedure: 1. with concentrated nitric acid, 2. with concentrated sulfuric acid, and 3. with concentrated hydrochloric acid.
The reactions of metals with nitric acid and concentrated sulfuric acid are different from reactions of metals with hydrochloric acid,
dilute sulfuric acid and dilute acetic acid.
Although copper does not react with dilute acids or with concentrated hydrochloric acid, it does react with both dilute and
concentrated nitric acids and with hot concentrated sulfuric acid but does not produce hydrogen gas in reaction with them.
The residual mixtures contain solutions of salts but writing equations for the reactions is difficult because more than one reaction can
occur simultaneously between copper or magnesium or zinc and nitric acid.
For example when zinc reacts with nitric acid the reaction may produce nitrogen dioxide, nitric oxide, nitrous oxide, zinc nitrate and
ammonium nitrate.

12.3.12 Concentrated acids with metals, nitric acid with copper
Nitric acid reacts with metals above platinum in the reactivity series, but does not form hydrogen gas.
BE CAREFUL! DO THIS EXPERIMENT IN A FUME CUPBOARD.
Pour drops of concentrated nitric acid on pieces of copper in a test-tube.
Put a stopper on the test-tube immediately because brown nitrogen dioxide gas forms.
The nitric acid acts as an oxidizing agent and is reduced to nitrogen dioxide and water.
The reaction is exothermic.
Cu (s) + 4HNO3 (aq) --> Cu(NO3)2 (aq) + 2H2O (l) + 2NO2 (g).

12.3.13 Sulfuric acid with copper
Concentrated acids should be handled only by experienced science teachers.
Concentrated sulfuric acid reacts with metals above platinum in the reactivity series, but does not form hydrogen gas.
BE CAREFUL! DO THIS EXPERIMENT IN A FUME CUPBOARD.
Add hot concentrated sulfuric acid to a piece of copper foil.
Brown nitrogen dioxide gas forms.
The sulfuric acid acts as an oxidizing agent.
Cu (s) + 2H2SO4 (aq) --> CuSO4 (aq) + 2H2O (l) + SO2 (g).

12.3.14 Concentrated acids with a non-metal, carbon
DO NOT DEMONSTRATE THIS EXPERIMENT!
Hot sulfuric acid and nitric acid can react as oxidizing agents with carbon.
Carbon is oxidized to carbon dioxide and nitric acid is reduced to nitrogen dioxide and water.
C (s) + 4HNO3 (aq) --> CO2 (g) + 4NO2 (g) + 2H2O (l).

12.3.15 Dilute acids with salts
1. Add small quantities of sodium chloride, sodium nitrate, sodium acetate, sodium sulfite and iron sulfide to about 5 mL of dilute
hydrochloric acid in separate test-tubes.
Observe what happens when the mixtures are cold and when they are warmed.

2. Repeat the procedure using dilute sulfuric acid and then concentrated sulfuric acid.
3. Dilute acids do not react with chlorides, nitrates, sulfates, or acetates unless the metal ions in the salt can form an insoluble salt with
the ions in the acid.
4. Acids react with sulfites to produce sulfur dioxide, water and a salt.
5. Acids react with sulfides to produce hydrogen sulfide (rotten egg gas) and a salt.
6. Concentrated sulfuric acid reacts with chlorides to produce hydrogen chloride and a sulfate.
7. Concentrated sulfuric acid reacts with nitrates to produce nitric acid and a sulfate.
8. Concentrated sulfuric acid reacts with acetates to produce acetic acid and a sulfate.

12.3.16 Acid dissociation constant, acidity constant, acid-ionization constant
1. The acid dissociation constant, Ka, measures the strength of an acid in solution.
2. An acid, HA, dissociates into A-, conjugate base, and H+, hydrogen ion (proton).
The equilibrium equation when concentrations do not change is: HA <--> A- + H+.
3. Dissociation refers to the break up of a molecule into smaller molecules, atoms or ions.
In a buffer solution of the salt of a weak acid with a weak acid, the dissociation of the weak acid is negligible, but a salt may be
dissociated completely into ions.
4. The dissociation constant, Ka (acid dissociation constant, acidity constant, acid-ionization constant), is the equilibrium constant of
a reversible dissociation including the ionization reactions of acids and bases in water.
The dissociation constant Ka = [A-] [ H+] / [HA] in mol / litre.
5. However, dissociation is usually expressed as a logarithmic constant, pKa, where pKa = -log10 (1/Ka)
It is the quotient of the equilibrium concentrations, in mol/L for ionization reactions at 25oC.
For pKa, the larger the value the weaker the acid, so strong acids have pKa < 2, and weak acids have pKa >2, < 12.
6. Confusion occurs because both Ka and pKa are both called "acid dissociation constant".

12.4.0 Hydrochloric acid
Hydrochloric acid is an aqueous solution of hydrogen chloride gas.
Hydrochloric acid dissolves most metals to form chlorides and hydrogen gas.
Hydrochloric acid is available as:
1. 5.0 M, 4.0 M, 2.0 M, 1.0 M and 0.5 M volumetric solutions
2. Minimum assay 36% solution density 1.17 g cm-3 at 20oC
3. 36% "ANALAR" solution
4. Sold as "muriatic acid", and used in the building trades.

12.9.0 Phosphoric acid
Ionization reaction
H3PO4 + H2O <--> H3O+ + H2PO4-
H2PO4- + H2O <--> H3O+ + HPO42-
HPO42- + H2O <--> H3O+ + PO43-.

12.10.0 Boric acid, ionization reaction
1. Orthoboric acid, trioxoboric acid (III) acid, boracic acid, sassolite, H3BO3 is a weak acid.
White to colourless triclinic crystals, MP 169oC, occurs in volcanic steam vents, slightly soluble in cold water, used to make
borosilicate glass, used in buffer solutions, detergents and in pharmacy, e.g. "boracic powder" for eye infections.
Action of continuous heat: boric acid, H3BO3 --> metaboric acid + water, H2B4O4 --> tetraboric acid
(pyroboric acid) H2B4O7 --> boriolved.
Leave to cool to see fine white crystals form.

Table 1.0 Abbreviations, chemistry
Metal 2M Hydrochloric acid 2M Sulfuric acid
Magnesium very rapid rapid
Aluminium slight none
Zinc moderate Slight
Iron very slight very slight
Tin none none
Lead none none
Copper none none
alc. alcohol L
litre
alk. alkali M
molar conc. e.g. 2 M (2 molar)
aq. water MP melting point
bp
boiling point max. maximum
cryst. crystals min. minimum
decomp. decomposes mL millilitre
del. deliquescent mm millimetre (10-3 m)
dil. dilute non-vol. non-volatile
F P
freezing point org. organic
g / mL r.d. ox. oxidized
g gram polyp. polypropylene
ign. ignition ppt. precipitate
ind. indicator PVC polyvinyl chloride
inorg. inorganic soln. solution
insol. insoluble W / V weight to volume ratio
kg. kilogram W / W weight to weight ratio