How many isotopes of Hydrogen are there? Give their names.

Which hydride among the following is less stable?

Heavy water is:

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

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

Write a note on metallic or non-stoichiometric hydrides.