$5.75 \ mg$ of sodium vapour is converted to sodium ion. If the ionisation energy of sodium is $490 \ kJ \ mol^{-1}$ and atomic weight is $23 \ g \ mol^{-1}$,the amount of energy needed for this conversion will be (in $kJ$)

The ratio of amounts of $H_2S$ needed to precipitate all the metal ions from $100 \ mL$ of $1 \ M$ $AgNO_3$ and $100 \ mL$ of $1 \ M$ $CuSO_4$ is

$A$ gaseous mixture contains $CH_4$ and $C_2H_6$ in equimolecular proportion. The weight of $2.24 \ L$ of this mixture at $NTP$ is .............. $g$.

$A$ sample of nitric acid has a density of $1.41 \ g \ mL^{-1}$ and the mass percentage of nitric acid is $69 \%$. Calculate the concentration of nitric acid in the sample in moles per liter. (in $M$)

Dissolving $1.24 \ g$ of white phosphorus in boiling $NaOH$ solution in an inert atmosphere gives a gas $Q$. The amount of $CuSO_4$ (in $g$) required to completely consume the gas $Q$ is. . . . [Given: Atomic mass of $H = 1, O = 16, Na = 23, P = 31, S = 32, Cu = 63$]

$120 \ g$ of urea are present in $5 \ L$ of solution. The active mass of urea is: