Hydrogen and deuterium differ in

Which of the following statements about $H_2SO_4$ is incorrect?

Which one of the following statements is not correct for ortho and para hydrogen?

Which of the following statements is not correct regarding the hydrogen atom?

Exhausted permutit does not contain ....... ion.

Identify the correct statements about the hydrides.
$(I)$ In saline hydrides,the oxidation state of hydrogen is $-1$.
$(II)$ $LaH_{2.87}$ is an example of an interstitial hydride.
$(III)$ $NH_3$ and $H_2O$ have the tendency to form hydrogen bonds.
$(IV)$ Electrolysis of molten sodium hydride liberates $H_2$ gas at the anode.