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?

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?

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?

Consider the following substances:

NaCI, Ca(OH)₂, NaHCO₃, NH₃, Na₂CO₃, H₂O, Cl₂, CO₂, CaSO₄.2H₂O, 2CaSO₄.H₂O, 2CaSO₄.2H₂O, CaOCI₂

(a) Which two substances combine to form bleaching powder?

(b) Which four substances are utilized in the production of washing soda? (c)Which compound represents plaster of Paris?

(d) Which compound is a part of baking powder?

(e) Which compound is used as an antacid?

Give one example each of a salt which gives an aqueous solution having

(a) pH less than 7

(b) pH equal to 7

(c) pH more than 7