(a) While diluting an acid, why is it recommended that the acid should be added to water
and not water to the acid?
(b) Explain why aqueous solution of an acid conducts electricity.
(c) 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 their H+ ion concentration.
(iii) State the change in colour of the pH paper on dipping in solution C and D.
Answers
Answer & Explanation:
(a) Dilution of concentrated acid is an exothermic process. If water is added to a concentrated acid, the heat generated may cause the mixture to splash out and cause burns. When the acid is added to water slowly with constant stirring, the mixture will not splash out.
(b)Acids undergo dissociation in aqueous solution to form H+ ions. When electricity is passed through an aqueous solution of an acid, the H+ ions reach the cathode and each H+ ion picks up one electron from the cathode to form H2 gas. Because of this reaction, an aqueous solution of acid conducts electricity.
(c) (i) The order for acid is ( highest to lowest):
6 that is A and then 7 that is D
The order for basic is ( highest to lowest):
12 that is C and then 9 that is B.
Hope this helps!!