Give one significant observation when:

(a) a solution of barium chloride is added to zinc sulphate solution.

(b) lead nitrate is heated in a test tube.

(c) chlorine gas is passed over moist starch iodide paper.

A gas cylinder can hold 150 g of hydrogen under certain conditions of temperature and pressure. If an identical cylinder with the same capacity can hold 450 g of gas ‘G’ under the same conditions of temperature and pressure, find:

(a) the vapour density of the gas ‘G’.

(b) the molecular weight of gas ‘G’.

Name the gas produced during each of the following reactions:

(a) When copper is treated with hot, concentrated nitric acid.

(b) When ammonia is burnt in an atmosphere of oxygen.

(c) When ferrous sulphide reacts with dilute hydrochloric acid.

Study the table given below. Use only the letters given in the table to answer the questions. Do not identify the elements.

(a) State the valency of element ‘G’.

(b) Which element can exhibit catenation?

(c) Write the formula of the compound formed between ‘M’ and ‘P’.