Hydrogen can be prepared with the help of cold water. Give a reaction of hydrogen with :
(a) a monovalent metal
(b) a divalent metal.
Reaction of hydrogen with metals gives metal hydrides.
Group-1 alkali metals are monovalent metals.
reaction : 2M + H2 → 2MH
where M = Li, Na, K etc
Group-2 alkaline earth metals are divalent metals.
reaction: M + H2 → MH2
where M = Be, Mg, Ca etc