Give reasons:

(a) Covalent compounds have low melting point.

(b) For covalent bond formation both atoms should have high ionisation.

(c) Covalent bond formation takes place when both atoms should have four or more electron in outermost shell.

Glucose or blood sugar has the molecular formula C₆H₁₂O₆. Determine % of each element.

(a) State whether the following statements are true or false. Justify your answer.

(1) Electrolysis of molten lead bromide is considered to be a redox reaction.

(2) Copper is a good conductor of electricity but it is a non-electrolyte.

(b) State the reaction occurring at the anode during electrolysis of copper sulphate solution using a copper anode and platinum anode respectively.

Choose the answer from the list which fits the description.

[O₂, NO₂, H₂S, C₂H₂, KBr]

(a) A colourless gas liberated on decomposition of nitric acid.

(b) Water is added to calcium carbide.

(c) Dilute hydrochloric acid is added to zinc sulphide.