In which of the following processes is the highest purity $(99.9 \%)$ hydrogen obtained?

Under normal conditions,the hydrogen molecule is not reactive because .........

Complete the following reactions:
$(i) \, H_{2(g)} + M_m O_{o(s)} \xrightarrow{\Delta }$
$(ii) \, CO_{(g)} + H_{2(g)} \xrightarrow[catalyst]{\Delta }$
$(iii) \, C_3 H_{8(g)} + 3 H_2 O_{(g)} \xrightarrow[catalyst]{\Delta }$
$(iv) \, Zn_{(s)} + NaOH_{(aq)} \xrightarrow{heat}$

Write the isotopes of hydrogen and specify the number of protons,electrons,and neutrons in each.

What happens when ionic hydrides of $s$-block elements in molten state are electrolysed?

Pure dihydrogen $(99.95\%)$ is obtained by the electrolysis of