When a solution of 500ml 2M KOH is added to 500ml 2M HCl, then rise in temperature is T1, when the same experiment is repeated by mixing 250 ml of each solution then rise in temperature is T2 then,

In the first case, double equivalents of water is produced than the later case. Moreover, the final volume in the first case is double than the second. Accordingly, the final mass in the first case is double than that of the second.

If q heat increases the temperature ${\mathrm{T}}_1$ of a system of mass m then, q/2 heat increases the temperature ${\mathrm{T}}_1$ of a system of mass m/2