This question relates to the preparation of Nitric acid on a large scale.

(a) Name the reactant used in this process.

(b) State the conditions under which the reactions occur.

'M' is an element above lead in the activity series of metals. Select the correct answer in each case from (i) to (iii).

(a) M - 3e^- ⟶ M³⁺: The process takes place by oxidation/reduction.

(b) M³⁺ ⟶ M: The cation gets reduced/oxidised to neutral atom.

(c) M reacts with dil. H₂SO₄ - to liberate hydrogen/sulphur dioxide gas.

Write the reaction taking place at the cathode and anode in the following process shown by a diagram.

In an Experiment, 6.21 g of lead is combined with 4.26 g of chlorine. What is the empirical formula of the resulting compound?