Explain molarity and molality in short.

(N/A) Molarity $(M)$ is defined as the number of moles of solute dissolved in one litre (or one cubic decimeter) of solution.
Molarity $= \frac{\text{Moles of solute}}{\text{Volume of solution in litre}}$
For example,a $0.25 \ mol \ L^{-1}$ (or $0.25 \ M$) solution of $NaOH$ means that $0.25 \ mol$ of $NaOH$ is dissolved in one litre of solution.
Molality $(m)$ is defined as the number of moles of solute per kilogram $(kg)$ of solvent.
Molality $(m)$ $= \frac{\text{Moles of solute}}{\text{Mass of solvent in } kg}$
For example,a $1.00 \ mol \ kg^{-1}$ (or $1.00 \ m$) solution of $KCl$ means that $1 \ mol$ $(74.5 \ g)$ of $KCl$ is dissolved in $1 \ kg$ of water.
Note: Mass percentage,ppm,mole fraction,and molality are independent of temperature,whereas molarity depends on temperature because volume changes with temperature.