Question

The following table gives the solubility at different temperatures Answer the question based on this.

Temperature in Kelvin

Substance dissolved	283	293	313	333	353
KNO3	21	32	62	106	167
NaCl	36	36	36	36	37
KCl	35	35	40	46	54
NH4Cl	24	37	41	55	66

What is the effect of a change in temperature on the solubility of a salt?

Answer 1

Solubility: The maximum amount of solute that can dissolve in a known quantity of solvent at a certain temperature is its solubility.

• The solubility of most of the salt rises with an increase in temperature.
• This is because with an increase in temperature, the kinetic energy of the molecules increases, and the solvent molecules break apart the solute molecules that are held together by intermolecular attractions more effectively.
• Also for most ionic compounds, the change in enthalpy is positive and hence the dissolution process is endothermic.
• For an endothermic reaction, an increase in temperature leads the reaction to a forwarding reaction.
• In the given table as the temperature is increasing solubility is increasing.