. An aqueous solution ‘A’ turns phenolphthalein solution pink. On addition of an aqueous solution ‘B’ to ‘A’, the pink colour disappears. The following statement is true for solution ‘A’ and ‘B’
(i) A is strongly basic and B is a weak base.
(ii) A is strongly acidic and B is a weak acid.
(iii) A has pH greater than 7 and B has pH less than 7
(iv) A has pH less than 7 and B has pH greater than 7

(iii) A has pH greater than 7 and B has pH less than 7

Explanation:

Phenolphthalein is a common indicator in acid base titrations. It turns pink in basic conditions and turns colorless in acidic conditions. Thus on addition of solution A it becomes pink so A should be basic having pH more than 7. On addition of B , it turn out to be colorless means that B is an acidic solution having pH less than 7.

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).