Question

(a) What does the pH of a solution signify? Three solution A, B and C have pH values of 6, 4 and 10 respectively. Which of the solutions is highly acidic?
(b) A farmer has found that the pH of soil in his fields is 4.2. Name any two chemical materials which he can mix with the soil to adjust its pH.

Answer 1

(a) The pH of a solution signifies whether it is an acid or a base and also its strength. Solutions with a pH greater than 7 are considered basic or alkaline, solutions with a pH less than 7 are acidic, and solutions with a pH of 7 are considered neutral.
Solution B with the lower pH value of 4 is highly acidic.

(b) If the pH of the soil is 4.2, then it is highly acidic. Hence, the soil should be treated with chemicals (bases) such as quick lime (calcium oxide) or slaked lime (calcium hydroxide).