On reaction with $Mg$,very dilute nitric acid produces

When $1:2$ equivalence ratio of the gases $X$ and $Y$ are heated to $573 \ K - 673 \ K$ at $200-300 \ atm$ in the presence of $ZnO-Cr_2O_3$ catalyst,methanol is formed. Here,the gases $X$ and $Y$ are $X$ and $Y$ respectively.

Which of the following is distilled first during the fractional distillation of liquid air or mixtures of these gases?

The calorific value of producer gas is low because of:

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

From which source is the maximum amount of hydrogen obtained?