If $0.5 \ g$ of a mixture of two metals $A$ and $B$ with respective equivalent weights $12$ and $9$ displace $560 \ mL$ of $H_2$ at $STP$ from an acid,the composition of the mixture is:

The combustion of methane is represented by the following equation: $CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(l); \Delta H = -890 \, kJ \, mol^{-1}$. How many grams of carbon dioxide are produced when $445 \, kJ$ of heat is released?

The volume of $0.04 \ M$ aqueous solution of $HNO_3$ required to neutralize $50 \ mL$ of $0.01 \ M$ aqueous solution of $Ba(OH)_2$ is (Assume complete neutralization). (in $mL$)

Equal masses of $SO_2$,$CH_4$,and $O_2$ are placed in an empty container at $298 \ K$. The total pressure is $2.1 \ atm$. What is the partial pressure of $CH_4$ in the mixture in $atm$?

At $T \ K$, $100 \ L$ of dry oxygen is present in a sealed container. It is subjected to silent electric discharge, until the volumes of oxygen and ozone become equal. What is the volume (in litres) of ozone formed at $T \ K$?

$A$ $1.85 \ g$ 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