What volume of ammonia is required to react with $250 \ mL$ of oxygen by following the reaction at same conditions?
$4NH_3(g) + 5O_2(g) \to 4NO(g) + 6H_2O(g)$

$P_4O_6$ 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 $mL$)

The normality of $1 \ M$ solution of $H_3PO_4$ will be.....$N$

$A$ mixture of $H_2$ and $O_2$ at $1 \, atm$ pressure contains $20 \%$ by weight of $H_2$. Find out the partial pressure of $H_2$ in $atm$.

$A$ $1.85 \ g$ sample of an arsenic containing pesticide was chemically converted to $AsO_4^{3-}$ (atomic mass of $As = 74.9$) and titrated with $Pb^{2+}$ to form $Pb_3(AsO_4)_2$. If $20 \ mL$ of $0.1 \ M \ Pb^{2+}$ is required to reach the equivalence point,the mass percentage of arsenic in the pesticide sample is closest to

What is the volume occupied by $0.5 \ mol$ of $CO_2$ at $STP$ (in $dm^3$)?