The density of '$x$' $M$ solution ('$x$' molar) of $NaOH$ is $1.12 \ g \ mL^{-1}$. While in molality,the concentration of the solution is $3 \ m$ $(3 \ molal)$. Then '$x$' is.
(Given: Molar mass of $NaOH$ is $40 \ g \ mol^{-1}$)

If $80 \ g$ of copper sulphate $CuSO_{4} \cdot 5H_{2}O$ is dissolved in deionised water to make $5 \ L$ of solution. The concentration of the copper sulphate solution is $x \times 10^{-3} \ mol \ L^{-1}$. The value of $x$ is .... .
[Atomic masses: $Cu = 63.54 \ u, S = 32 \ u, O = 16 \ u, H = 1 \ u$]

The mass $\%$ of urea solution is $6$. The total weight of the solution is $1000 \ g$. What is its concentration in $mol \ L^{-1}$? (Density of water $= 1.0 \ g \ mL^{-1}$)
$(C = 12 \ u, N = 14 \ u, O = 16 \ u, H = 1 \ u)$

What will be the molality of $10\%$ w/w aqueous solution of $NaOH$ (in $m$)? (Molecular mass of $NaOH = 40 \ g \ mol^{-1}$)

The molality (in $mol \ kg^{-1}$) of $1 \ mol$ of solute in $50 \ g$ of solvent is

The molarity of the solution obtained by mixing $750 \ mL$ of $0.5 \ (N) \ HCl$ with $250 \ mL$ of $2 \ (M) \ HCl$ is ........... $M$.