Give reasons in one or two sentences for the following: The mixture of hydrazine and hydrogen peroxides with a copper `(II)` catalyst is used as a rocket propellant.

Explanation

The reaction between hydrazine and`H_2 O_2` in the presence of Cu(II) is highly exothermic and is accompanied by a large increase in volume of the products. Therefore, this mixture is used as a rocket propellant.
`2H_2 O_2 (l) + underset("Hydrazine")(H_2 "NN" H_2 (l)) overset(Cu(II))to N_2 (g) uarr + 4H_2 O(g) uarr`