State one observation :

(a) Concentrated nitric acid is reacted with sulphur.

(b) Lead nitrate is heated strongly in a test tube.

(c) Zinc nitrate crystals are strongly heated.

(d) when crystals of copper nitrate are heated in a test tube.

What is the property of nitric acid which allows it to react with copper?

X, Y and Z are three crystalline solids which are soluble in water and have a common anion.
To help you to identify X, Y and Z, you are provided with the following experimental observations. Copy and complete the corresponding inferences in (a) to (e).

(a) A reddish-brown gas is obtained when X, Y and Z are separately warmed with concentrated sulphuric acid and copper turning added to the mixture.

INFERENCE 1: The common anion is the …………… ion.

(b) When X is heated, it melts and gives off only one gas which re-lights a glowing splint.

INFERENCE 2: The cation in X is either …………… or ……………

(c) The action of heat on Y produces a reddish-brown gas and a yellow residue which fuses with the glass of the test tube.

INFERENCE 3: The metal ion present in Y is the …………… ion.

(d) When Z is heated, it leaves no residue. Warming Z with sodium hydroxide solution liberates a gas which turns moist red litmus paper blue.

INFERENCE 4: Z contains the …………… cation.

(e) Write the equations for the following reactions.

1. X and concentrated sulphuric acid (below 200° C). (One equation only for either of the cations given in INFERENCE 2).
2. Action of heat on Y.
3. Concentrated nitric acid is added to copper turnings kept in a beaker.

The diagram given below is a representation of the Industrial preparation of Nitric acid by Ostwald's process. With respect to the process, answer the following questions :

(a) Write the temperature and the catalyst required during the catalytic oxidation of ammonia.

(b) Give balanced chemical equation for the reaction occurring during the conversion of nitrogen dioxide to nitric acid.