On heating a mixture of $NH_4Cl$ and $KNO_2$,we get:

Which of the following is used to dry ammonia gas?

Hydrogen iodide cannot be prepared by the action of concentrated $H_2SO_4$ on potassium iodide because:

Which of the following substances is used as a dehydrating agent in the laboratory?

Identify the reactions in which $H_2$ is liberated? $(i)$ $Zn + NaOH_{(aq)} \longrightarrow$ $(ii)$ $HCOOH \xrightarrow[\text{Conc. } H_2SO_4]{373 \ K}$ $(iii)$ $CH_{4(g)} + H_2O_{(g)} \xrightarrow[Ni]{1270 \ K}$ $(iv)$ $Zn + H^+_{(aq)} \longrightarrow$ $(v)$ $C_{(s)} + H_2O_{(g)} \xrightarrow{1270 \ K}$

What do you understand by the term non-stoichiometric hydrides? Do you expect this type of hydrides to be formed by alkali metals? Justify your answer.