The equation below shows the reaction between element 'X' and dilute sulphuric acid.

X(s) + H₂SO₄ (aq.) ⟶ XSO₄ (aq.) + H₂ (g)

Which particles are responsible for conducting electricity in dilute sulphuric acid and compound XSO₄?

1. Electrons
2. Only positive ions
3. Only negative ions
4. Both positive and negative ions

Methanol and ethanol belong to the same homologous series. What does this statement mean?

1. Their molecules contain atoms only of carbon and hydrogen.
2. Their molecules have the same number of carbon atoms.
3. They have the same functional group.
4. They have the same relative molecular mass.

In the process of Electrorefining of Copper shown in the diagram below, which of the following statements is correct?

1. The anode is made of pure Copper.
2. The cathode is made of impure Copper.
3. Copper is deposited at the anode.
4. Copper ions from the anode move to the cathode and get deposited as pure Copper.

Electroplating steel objects with silver involves a three-step process.

Step 1 — A coating of copper is applied to the object.

Step 2 — A coating of nickel is applied to the object.

Step 3 — The coating of silver is applied to the object.

(a) A diagram of the apparatus used for step 1 is shown.

1. The chemical process taking place on the surface of the object is
   Cu²⁺(aq) + 2e^- ⟶ Cu (s)
   What is the observation seen on the surface of the object?

2. Explain why the concentration of copper ions in the electrolyte remains constant throughout step 1.

(b) Give two changes which would be needed in order to coat nickel onto the object in step 2.

(c) Write down the reaction taking place at the positive electrode during step 3.