In the Victor Meyer method,$0.2 \ g$ of a volatile substance displaces $56 \ mL$ of air at $STP$. The molar mass of the substance is:

At sea level,the dry air mass percentage composition is given as nitrogen gas: $70.0$,oxygen gas: $27.0$,and argon gas: $3.0$. If the total pressure is $1.15 \ atm$,calculate the ratio of the following respectively:
$(i)$ partial pressure of nitrogen gas to partial pressure of oxygen gas
$(ii)$ partial pressure of oxygen gas to partial pressure of argon gas
(Given: Molar mass of $N_2$,$O_2$,and $Ar$ are $28, 32$,and $40 \ g \ mol^{-1}$ respectively)

What is the mass in $g$ of $70\%$ $H_2SO_4$ required for the neutralization of $1$ mole of $NaOH$?

$20 \ g$ of iron pyrite,$FeS_2$,is roasted completely and the $SO_2$ gas produced is absorbed completely in $400 \ mL$ of $NaOH$ solution. If only $50\%$ of the $NaOH$ is used in the reaction,what was the molarity of the $NaOH$ solution?

How much of $NaOH$ (in $g$) is required to neutralize $1500 \ cm^3$ of $0.1 \ N \ HCl$? (Given: $Na = 23, O = 16, H = 1$)

The density of a gas at $STP$ is $2.86 \, g \, L^{-1}$. Which of the following is the gas?