Hydrogen question bank (Chemistry)

The mass of iron converted into $Fe_3O_4$ by the action of $18$ g of steam is :
(Given : Molar mass of H, O and Fe are $1$, $16$ and $56$ g mol$^{-1}$ respectively)
Assume iron is present in excess :

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : Isotopes of hydrogen have almost same chemical properties, but difference in their rates of reactions.

Reason R: Isotopes of hydrogen have different enthalpy of bond dissociation.

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