Question

which out of molality and molarity which is better

Answer 1

Molarity and molality are both measures of concentration of solutions. One is the ratio of moles to volume of the solution and the other isthe ratio of molesto the mass of the solution.
Molality is better than the molarity concentration in chemisrtry pratical calculation becauseConcentrations in molality (moles of solute per kilograms of solvent) are independent of temperature and pressure whereas concentrations in molarity (moles of solute per total volume of solution in liters) are not.