(i) Explain why is hydrochloric acid a strong acid and acetic acid, a weak acid ? How can it be verfied ?
(ii) Explain why equeous solution of an acid conducts electricity.
(iii) You have four solutions A, B,C and D. The pH of solution A is 6, B is 9, C is 12 and D is 7.
(a) Identify rhe most acidic and most basic solutions.
(b) Arrange the above four solutions in the increasing order of `H^(+)` ion concentration.
(c ) State the change in colour of pH paper on dipping in solution C and d.

Explanation

(i) Hydrochloric acid (HCl) is a stronger acid than acetic acid `(CH_(3)COOH)` because it releases `H^(+)` ions in aqueous solution more easily. In order to verify this, add a few drops of universal indicator solution in the test tubes containing the acids. It acquires red colour in hydrochloric acid (pH = 2)and yellow in acetic acid (pH = 4) which confirms that hydrochloric acid id stronger acid.
(ii) An awueous solutionos an acid (HA) releases ions in aqueous solution. These ions conduct electricity.
(iii) (a) Most acidic is A (pH = 6) and most basic is C (pH = 12).
(b) The increasing order of `H^(+)` ion concentration is : `C ltBltDltA.`
(c ) The pH paper acquires dark purple colour in solution C and green in solution D.