Gypsum $CaSO_4 \cdot 2H_2O$ on heating to about $120\ ^\circ C$ forms a compound which has the chemical composition represented by :-

Give two uses of $calcium \ carbonate$ $(CaCO_3)$?

Bleaching powder is obtained by passing chlorine on

Which of the following is an amphoteric hydroxide?

In India,during wedding ceremonies,a green flame is observed in fireworks. Which of the following elements is responsible for this?

$A$ compound $(A)$ is used in the preparation of washing soda to recover ammonia in the Solvay process. When $CO_2$ is bubbled through an aqueous solution of $(A)$,the solution turns milky. It is used in whitewashing due to its disinfectant nature. What is the chemical formula of $(A)$?