$1 \ g$ of a solute is added to $18 \ g$ of water. In this aqueous solution,what is the mass per cent of the solute (in $\%$)?

The normality of $4\% \ (w/V)$ $NaOH$ is

Sea water,which can be considered as a $6 \ M$ solution of $NaCl$,has a density of $2 \ g \ mL^{-1}$. The concentration of dissolved oxygen $(O_2)$ in sea water is $5.8 \ ppm$. Then the concentration of dissolved oxygen $(O_2)$ in sea water is $x \times 10^{-4} \ m$. $x = ............$ $(Nearest \ integer)$
Given: Molar mass of $NaCl$ is $58.5 \ g \ mol^{-1}$. Molar mass of $O_2$ is $32 \ g \ mol^{-1}$.

What will be the molarity of a solution containing $5 \ g$ of sodium hydroxide in $250 \ mL$ solution?

The molality of $648 \ g$ of pure water is .................. $m$.

If equal weights of $NaCl$ and $KCl$ are dissolved in the same volume of solution,how will the molarity of the two solutions compare?