Equal masses of methane $(CH_4)$ and oxygen $(O_2)$ are mixed in an empty container at $25\,^oC$. The fraction of the total pressure exerted by oxygen is:

The Molarity $(M)$ of an aqueous solution containing $5.85 \ g$ of $NaCl$ in $500 \ mL$ water is :
(Given : Molar Mass $Na: 23$ and $Cl: 35.5 \ g \ mol^{-1}$ )

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 $mL$)

One litre of hard water contains $12.00 \ mg$ of $Mg^{2+}$. The milli-equivalents of washing soda $(Na_2CO_3)$ required to remove its hardness is:

The amount of water produced (in $g$) in the oxidation of $1$ mole of rhombic sulphur by conc. $HNO_3$ to a compound with the highest oxidation state of sulphur is. . . . . (Given data : Molar mass of water $= 18 \ g \ mol^{-1}$)

What volume of $CO_{2(g)}$ at $STP$ is obtained by complete combustion of $6 \ g$ carbon (in $dm^3$)?