The total number of elements among $S$,$P$,$Zn$,$Al$,$Sn$,$Pb$ which produce $H_2$ gas with $NaOH$ is

What is the use of the alloy of lithium and lead (white metal)?

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

Consider the reaction:
$KOH + O_3 \to$ coloured solid $(a) +$ Gas $(b) + H_2O$
Select the $CORRECT$ statement.

Which of the following substances is used in gunpowder?

Why is $Li_{2}CO_{3}$ decomposed at a lower temperature whereas $Na_{2}CO_{3}$ at higher temperature?