The difference between heat of adsorption of ortho and para hydrogen is $......... \ kJ \ mol^{-1}$.

Which of the following is not an isotope of hydrogen?

Ortho-hydrogen and para-hydrogen resemble in which of the following properties?

Deuterium resembles hydrogen in chemical properties but reacts:

The number of neutrons and electrons,respectively,present in the radioactive isotope of hydrogen is:

Observe the following reactions:
$I$. $CO_{(g)} + H_{2(g)} \xrightarrow{X} HCHO_{(g)}$
$II$. $CO_{(g)} + 3 H_{2(g)} \xrightarrow{Y} CH_{4(g)} + H_2O_{(g)}$
The catalysts $X$ and $Y$ in the above reactions are respectively: