$20 \ g$ of hydrogen gas $(H_2)$ is present in a $5 \ L$ vessel. The molar concentration of hydrogen is: (in $M$)

The number of millimoles and milliequivalents of $Ba(OH)_2$ in $0.2 \, L$ of $0.2 \, M \, Ba(OH)_2$ solution are respectively:

$P_4O_6$ reacts with water according to the equation $P_4O_6 + 6H_2O \to 4H_3PO_3$. Calculate the volume of $0.1 \ M$ $NaOH$ solution required to neutralize the acid formed by dissolving $1.1 \ g$ of $P_4O_6$ in $H_2O$. (in $mL$)

$A$ $240 \ mL$ mixture of $CO_2$ and $CO$ is passed over red-hot coke. The $CO_2$ is completely reduced to $CO$. When the resulting gas is brought to the same temperature and pressure,the volume becomes $300 \ mL$. What is the volume of $CO$ in the original mixture in $mL$?

Methylation of $10 \ g$ of benzene gave $9.2 \ g$ of toluene. Calculate the percentage yield of toluene $......$. (Nearest integer)

What is the volume occupied by $2.5 \ mol$ of ammonia gas at $\text{STP}$ (in $dm^3$)?