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# Molarity of $H_2SO_4$ is 18M.If density is $1.8gcm^{-3}$,calculate its concentration in $mol kg^{-1}$ solvent $(H_2O)$ (ie) Molality.

$\begin{array}{1 1}\text{500 molal}\\\text{600 molal}\\\text{800 molal}\\\text{400 molal}\end{array}$

Molality (m) is related to molarity (M) by equation
$m=\large\frac{1000M}{1000\rho-MM_1}$
Where $M_1$ is the molar mass of $H_2SO_4$
$\therefore m=\large\frac{1000\times 18}{(1000\times 1.8-18\times 98)}$
$\Rightarrow 500$ molal