The charring of sugar,when treated with conc. $H_2SO_4$,is due to

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

The maximum sum of the number of neutrons and protons in an isotope of hydrogen is

Give the uses of $Dihydrogen$.

Which of the following statements is incorrect?

Calcium imide on hydrolysis gives gas $(B)$ which on oxidation by bleaching powder gives gas $(C)$. Gas $(C)$ on reaction with magnesium gives compound $(D)$ which on hydrolysis gives again gas $(B)$. Identify $(B)$,$(C)$ and $(D)$.