Why is the molarity of solutin independent of temperature?
Answers
A 1.0 m solution contains 1 mole of solute per kilogram of solvent.
Unit of molality is moles/ kg. Molality of solution does not change with the temperature of solution. In case of molality it is ratio of moles to mass. Mass is the same at any temperature hence molality wont change with change in temperature.
Molarity is defined as no of moles per litre of a solution.so we get the units of molarity as g/L.but we know from the fact pv=nrt that volume changes proportionally with temperature .therfore as volume increases molarity decreases and as temperature decreases molarity decreases.
Lets digest what i said by giving an example let molarity of the first and second solution be m1 and m2 and no of moles be n1 and n2 and volunes be v1 and v2.now for first as the temperature increases v1 increases therfore value of m1=n1/v1 decreases as smaller value of numerator by larger value of denominator is smaller value as compared to larger value of numerator to smaller value of denominator the latter one happens in the case when temperature decreases,as t decreases v decreases and the value of m2 becomes comparitively larger than m1
But all these points are defined for molarity as it contains volume,hence it is not temperature independent but varies with temeperature but on the other hand molality is no of moles of solute per 1kg of solvent hence its doesnt contain volume hence it is temeperature independent as it does not vary with temperature