$60 \ mL$ $NaOH$ solution is required for complete neutralization of $0.98 \ g$ orthophosphoric acid. The concentration of $NaOH$ solution is ............. $M$.

$12 \ g$ of $Mg$ (atomic mass $24$) will react completely with acid to give:

What is the volume occupied by $2 \ g$ of helium gas at $STP$ (in $dm^3$)? (molar mass of helium gas $= 4 \ g \ mol^{-1}$)

At $300 \ K$ and $1 \ \text{atm}$ pressure,$10 \ mL$ of a hydrocarbon required $55 \ mL$ of $O_2$ for complete combustion,and $40 \ mL$ of $CO_2$ is formed. The formula of the hydrocarbon is

$5.75 \ mg$ of sodium vapour is converted to sodium ion. If the ionisation energy of sodium is $490 \ kJ \ mol^{-1}$ and atomic weight is $23 \ g \ mol^{-1}$, the amount of energy needed for this conversion will be (in $kJ$)

$A$ solution of $H_2SO_4$ is $31.4 \%$ $H_2SO_4$ by mass and has a density of $1.25 \ g \ mL^{-1}$. The molarity of the $H_2SO_4$ solution is . . . . . . $M$ (nearest integer) [Given molar mass of $H_2SO_4 = 98 \ g \ mol^{-1}$]