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

A salt whose aqueous solution will have a pH of more than 7 will be:

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:

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?