$A$ solution contains $1.2046 \times 10^{24}$ hydrochloric acid molecules in one $dm^3$ of the solution. The strength of the solution is .......... $N$.

Which of the following is the correct formula to determine percent atom economy?

Amount of oxygen required for combustion of $1 \, kg$ of a mixture of butane and isobutane is ............. $kg$.

$A$ spherical ball of radius $7 \ cm$ contains $56 \ w\%$ iron. Find out the number of moles of iron present approximately in the ball (in $.1$)? $(d = 1.4 \ g \ cm^{-3}; \text{atomic mass} = 56 \ g \ mol^{-1})$

If $1 \, mole$ of $H_3PO_x$ is completely neutralized by $80 \, g$ of $NaOH$,select the correct statement :-

If the density of $1 \ mol$ of a gas at $NTP$ is $0.1784 \ g/L$,what is the weight of $1 \ mol$ of the gas in $g$?