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

Explanation​:
The student must be sufficiently familiar with the reactions covered in the syllabus to realize that sodium hydroxide would not be useful for producing a diol from an alkene. Alternatively, the question could be answered by recalling the use of sodium hydroxide in the other three reactions. The question is categorized as easy as only limited knowledge of reactions in the literature is needed.
Reactions B and C are both acid-base reactions where NaOH deprotonates the organic species.
Reaction D is a nucleophilic substitution of a halogenoalkane with OH− as the nucleophile.
Reaction A would require first halogenation (with e.g. Br2​) followed by nucleophilic substitution.

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

Explanation​:
Ethanoic acid is a weak acid and sodium hydroxide is a strong base. At the equivalence point, $\mathrm{pH}>7$, therefore the indicator chosen must have an endpoint>7(as determined by its pKa​).

Explanation:​
In electroplating, the anode is made of silver metal, which is oxidized to Ag^+ ions. The Ag^+ ions are then reduced at the cathode to Ag metal, resulting in a coating around this object.
Any impurities will sink to the bottom of the vessel.
In electrolytic cells, the anode is positive, and the cathode is negative. As a result, electrons travel from positive to negative.

Explanation​:
Non-spontaneous reactions take place in electrolytic cells using an external power supply.
The positive electrode is the anode where oxidation takes place.
The aqueous metal ion (Mx^+) is reduced at the cathode to produce the solid metal.

Explanation:​
Lewis acids are electron pair acceptors.
BF3 and AlCl3​ both have incomplete octets and so can accept a pair of electrons.
Electrophiles, by definition, are electron-deficient species that accept pairs of electrons. Nucleophiles are electron-rich species that donate pairs of electrons (Lewis bases).

Explanation​:
Weak acids produce strong conjugate bases. The salt when dissolved in solution would therefore be basic.

Explanation:​
NaOH is a base so reacts with a hydrogen ion. HNO3​, nitric acid, releases a hydrogen ion through the breaking (heterolysis) of the O-H bond.
This question is moderately difficult as the student must recognise that NaOH is a base and HNO3​ an acid and correctly interpret a structural formula that may be unfamiliar.

Explanation:​
A tenfold decrease in [H+], leads to a pH increase of 1.

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:​
H2O is more readily oxidized than Cl^− and SO4^2−, however, when concentrated aqueous NaCl is used, chlorine is produced at the anode

Explanation​:
$\mathrm{l}$ is a neutral salt, Na2CO3 is a basic salt, and NaOH is a strong base.

Explanation​:
$)$ gains electrons and is reduced to $\mathrm{Zn}(\mathrm{s})$ at the cathode. $\mathrm{l})$ loses electrons and is oxidised to Cl2(g) at the anode

Explanation​:
NH3​ has a non-bonding pair of electrons it can donate to a central metal ion. BH3​ and CH4 do not have non-bonding electrons.

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

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

Explanation:​
ΔGθ = $-$.
For spontaneous reactions, ΔGθ is negative, therefore Ecellθ​ must be positive.

Explanation:​
The student must identify the reagents and conditions for three reactions. Only information stated explicitly in the syllabus is needed and no interpretation of structural formulas is required. This question is therefore, categorized as “easy”.
Alkenes react with HCl in an addition reaction, alkanes react with halogens in the presence of UV light through free radical substitution, and halogenoalkanes react with NaOH in a nucleophilic substitution reaction.

Explanation:​
The HPO4^− ion contains two negatively charged oxygen atoms which can bond to hydrogen ions, producing phosphoric acid (H3PO4​).
The HPO4^− 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 HPO4^− is derived from H3PO4​.