Which of the following is $NOT$ true regarding the usage of hydrogen as a fuel?

Calcium imide on hydrolysis will give gas $(B)$ which on oxidation by bleaching powder gives gas $(C)$. Gas $(C)$ on reaction with magnesium gives compound $(D)$. $(D)$ on hydrolysis gives again gas $(B)$. $(B)$,$(C)$ and $(D)$ are

Pure hydrogen is obtained by carrying out the electrolysis of:

State the abundance and symbol of protium and deuterium in hydrogen atoms.

Complete the following reactions:
$(i)$ $H_{2(g)} + M_mO_{o(s)} \xrightarrow{\Delta} M_{(s)} + H_2O_{(l)}$
$(ii)$ $CO_{(g)} + 2H_{2(g)} \xrightarrow{\Delta, \text{ catalyst}} CH_3OH_{(l)}$
$(iii)$ $C_3H_{8(g)} + 3H_2O_{(g)} \xrightarrow{\Delta, \text{ catalyst}} 3CO_{(g)} + 7H_{2(g)}$
$(iv)$ $Zn_{(s)} + 2NaOH_{(aq)} \xrightarrow{\text{heat}} Na_2ZnO_{2(aq)} + H_{2(g)}$

In an ice crystal,each water molecule is hydrogen bonded to $.......$ neighbouring molecules.