Ortho- and para-hydrogens have

Arrange the following:
$(i)$ $CaH_{2}$,$BeH_{2}$,and $TiH_{2}$ in order of increasing electrical conductance.
$(ii)$ $LiH$,$NaH$,and $CsH$ in order of increasing ionic character.
$(iii)$ $H-H$,$D-D$,and $F-F$ in order of increasing bond dissociation enthalpy.
$(iv)$ $NaH$,$MgH_{2}$,and $H_{2}O$ in order of increasing reducing property.

Which of the following is the water-gas shift reaction?

The hydrides of which group elements are examples of electron-precise hydrides?

In which of the following reactions,hydrogen is acting as an oxidising agent?

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