P and Q are aqueous solutions of sodium chloride and sodium hydroxide, respectively. Which of these will turn:

(a) blue litmus red?

(b) red litmus blue?

A salt is dissolved in water and the pH of this salt solution is measured with a universal indicator paper. If the pH of solution is less than 7, the salt is most likely to be:

Which of the following salts will give an aqueous solution having pH of almost 7?

The metal salt A is blue in colour. When salt A is heated strongly over a burner, then a substance B is eliminated and a white powder C is left behind. When a few drops of a liquid D are added to powder C, it becomes blue again. What could be A, B, C and D?

When the concentrated aqueous solution of substance X is electrolyzed, then NaOH, CI₂ and H₂ are produced.

Name the substance X. What is the special name of this process?