Complete the blanks (i) to (v) in the passage given, using the following words. [Ammonium, reddish brown, hydroxyl, nitrogen dioxide, ammonia, dirty green, alkaline, acidic].

In the presence of a catalyst, nitrogen and hydrogen combine to give (i) ………….. gas. When the same gas is passed through water, it forms a soln. which will be (ii)………….. in nature, and will contain the ions (iii) ………….. and (iv) …………… . A (v) ………….. coloured ppt. of iron [II] hydroxide is formed when the above solution is added to iron [II] sulphate solution.

Name the gas evolved when the following mixtures are heated :

(i) Calcium hydroxide and Ammonium chloride.

(ii) Sodium nitrite and Ammonium chloride.

From the list of the gases — Ammonia, ethane, hydrogen chloride, hydrogen sulphide, ethyne — Select the gas which is used as a reducing agent in reducing copper oxide to copper.

Pick the odd member from the list giving reasons:

(a) Ammonia, sulphur dioxide, hydrogen chloride, carbon dioxide.

(b) Copper oxide, aluminium oxide, sodium oxide, magnesium oxide.