Explanation​:
More reactive metals are more likely to lose electrons (be oxidised) and so, Zn(s) will lose electrons to produce Zn^2+(aq) .
Cu^2+(aq)will gain electrons forming Cu(s) leading to a decrease in Cu^2+(aq) concentration and a paler blue colour of the solution.
Electrons flow from the anode(Zn) to the cathode (Cu).

Explanation:​
Least reactive metal is the strongest oxidizing agent/ weakest reducing agent.
Z is the most reactive metal (can displace both X and Y), followed by Y(can only displace X), and lastly, X (cannot displace any).

Explanation​:
By definition an acid is a proton donor. Weak acids only partially dissociate in aqueous solution leading to poor conductivity

Explanation​:
Acidic solutions have high H^+ concentrations. Bases have a high concentration of OH^− ions

Explanation:​
Students must compare ways of breaking bonds. They must recall that homolytic fissions form free radicals (species with unpaired electrons) as shared electrons split once the bond breaks.
In contrast, heterolytic fissions produce positively and negatively charged particles (ions) as both shared electrons go to just one of the atoms in the bond.

This question is categorized as hard. Students must recall the ways of breaking bonds, distinguish homolytic and heterolytic fission, and understand that free radicals have unpaired electrons.

Explanation:​

Hydrochloric acid produces chloride salts, nitric acid produces nitrate (NO3^−​) salts, sulphuric acid produces sulphate (SO4^2−​) salts, and ethanoic acid produces ethanoate (CH3​COO^−) salts.

Explanation​:
Cathode site of reduction, anode site of oxidation, use CROA to remember this.
Reduction is the gain of electrons.

Explanation​:
Metal oxides produce basic solutions when dissolved in water. Non-metal oxides produce acidic solutions when dissolved in water.
Silicon dioxide does not react with water, but reacts with concentrated alkalis to form silicates: SiO2(s)+2 OH−(aq)→SiO32−(aq)+H2O(l)

Explanation​:
The positive ions (cations) move in the direction of the cathode as the positive Cu2+ ions are used up.
Zn being more reactive than copper, Zn(s) is the anode where oxidation occurs, and Cu(s) is the cathode where reduction of Cu2+(aq) occur

Explanation:​
Spontaneous reactions occur in voltaic cells converting chemical energy to electrical energy, whereas, non-spontaneous reactions occur in electrolytic cells requiring electrical energy and converting this to chemical energy.
Electrolytic cells typically consist of one reaction vessel containing the aqueous of molten electrolyte. No salt bridge is therefore required.

Explanation:​

Acids react with carbonates to produce a salt, water, and carbon dioxide.

Explanation​:
NaOH is a strong base and so would release a high concentration of OH^− ions in water. Choices A and C are incorrect as HCl and H2SO4 are strong acids and would give low $\mathrm{pH}$s. $\mathrm{NaCl}$ is a neutral salt.

Explanation​:
By definition, the more readily an acid releases a proton, the less likely the conjugate base is to accept a proton.

Explanation​:
Step 1 is a free radical substitution, converting the alkane to a chloroalkane and producing HCl as a by-product.
Step 2 is a nucleophilic substitution, in which the C−Cl bond breaks and is replaced by a hydroxyl (C−OH) group; the products are an alcohol and sodium chloride.
Step 3 is an oxidation. To prevent the aldehyde from being oxidised further to a carboxylic acid, the product must be removed by distillation as it forms.

Explanation:​
A heterolytic fission involves the break up of a bond so that both electrons go to one of the atoms. This process produces ions, as shown below.

The heterolytic fission requested occurs like this:

The species produced are ions, (CH3)3C^+ and Br^−.

This question is categorized as hard. The student must interpret the condensed formula given, recall how heterolytic fissions occur in that specific bond, and predict the product of this process.

Explanation:​
The conjugate base of HCl is the compound produced when a hydrogen ion is removed. The conjugate base is therefore the chloride ion, Cl^−.
This question is hard as the student must link the names of chemicals to their formula and identify a conjugate base without the aid of an explicit reaction equation.

Explanation:​
Water accepts a hydrogen ion to produce H3O^+. This question is easy as the formation of H3O^+ is covered explicitly in the syllabus

Explanation​:
In electrolysis the positive electrode is the anode. Oxidation takes place at the anode.

Explanation:​
C3H8​ is a saturated alkane and C3H6​ is an unsaturated alkene. The test of unsaturation using Br2(aq) can demonstrate the presence or absence of a carbon-carbon double bond.
In the presence of a double bond, Br2(aq) can add across the double bond in the alkene producing a dibromo-alkane, and a change of color from brown to colorless will be observed.
In the case of the absence of a double bond (saturated hydrocarbon), no color change would occur.

Explanation:
Use the mnemonic CNAP; cathode negative, anode positive for the polarity in electrolytic cells.

Explanation:​
The HPO^4− ion contains two negatively charged oxygen atoms which can bond to hydrogen ions, producing phosphoric acid (H3PO^4​).
The HPO^4− ion can therefore react with two H+ ions.
This question is moderately difficult as the student must recognise that H^+ ions bond to the negatively charged oxygen atoms, or that HPO^4− is derived from H3PO^4​.

Explanation​:
Mg(s) loses electrons to produce $).$ Loss of electrons is oxidation which takes place at the anode.

Explanation:​
A conjugate acid-base pair differ by a single hydrogen ion. Carbonic acid and carbonate (choice A) differ by two hydrogen ions so are not a conjugate acid-base pair. Boric acid and its hydroxide adduct (choice B) differ by a hydroxide ion and ammonia and hydroxylamine (choice D) by an oxygen atom.
This question is categorised as very hard as the student must recall the definition of a conjugate acid-base pair, interpret the structural formulas of unfamiliar molecules and identify a conjugate acid and base without the aid of a reaction equation.