When 20 mL of a strong acid is added to 20 mL of an alkali, the temperature rises by 50C. If 200 mL of each liquid is mixed, the temperature rise will be

Heat evolved in the first case = 40 x 5 = 200 calHeat evolved in the second case = 10 times of the first, that is, 10 x 200 = 2000 cal.∴   2000 = 400 × ∆T  or ∆T = 50C.