Which hydride among the following is less stable?

Given below are two statements:

Statement-I : Methane and steam passed over a heated $$\mathrm{Ni}$$ catalyst produces hydrogen gas.

Statement-II : Sodium nitrite reacts with $$\mathrm{NH}_{4} \mathrm{Cl}$$ to give $$\mathrm{H}_{2} \mathrm{O}, \mathrm{N}_{2}$$ and $$\mathrm{NaCl}$$.

In the light of the above statements, choose the most appropriate answer from the options given below :

Given below are two statements: one is labelled as Assertion $$\mathbf{A}$$ and the other is labelled as Reason $$\mathbf{R}$$

Assertion A : Physical properties of isotopes of hydrogen are different.

Reason R : Mass difference between isotopes of hydrogen is very large.

In the light of the above statements, choose the correct answer from the options given below:

Given below are two reactions, involved in the commercial production of dihydrogen (H$$_2$$). The two reactions are carried out at temperature "T$$_1$$" and "T$$_2$$", respectively

$$C(s) + {H_2}O(g)\buildrel {{T_1}} \over \longrightarrow CO(g) + {H_2}(g)$$

$$CO(g) + {H_2}O(g)\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Catalyst}^{{T_2}}} C{O_2}(g) + {H_2}(g)$$

The temperatures T$$_1$$ and T$$_2$$ are correctly related as :