Which of these is used to reduce the acidity of soil?
Correct option is A. Calcium hydroxide
$$\textbf{Concept Applied:}$$ Acidic substance increases acidity or reduces basicity, and vice versa.
$$\textbf{Correct Option:}$$ A
$$\textbf{Explanation for correct option:}$$ For reducing acidity of soil, we need a basic substance. Of the given options, only calcium hydroxide is basic in nature.
$$\textbf{Explanation for incorrect options:}$$
(B) Ammonium sulphate is acidic, so it cannot be used as it will increase acidity.
(C) Ammonium nitrate is acidic, so it cannot be used as it will increase acidity.
(D) Ammonium chloride is acidic, so it cannot be used as it will increase acidity.