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.
(i) identify the most acidic and the most basic of the solutions.
(ii) Arrange the above four solutions in the increasing order of the H+ ion concentration.
(iii) State the change in colour of pH paper on dipping in solution C and D.

Explanation

(i) A is most acidic and C is most basic
(ii) C, B, D, A
(iii) When dipped in C, it turns blue while in D it turns green.