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.

Question

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