When 20 mL of a strong acid is added to 20 mL of an alkali, the temperature rises by 5°C. If 200 mL of each liquid is mixed, the temperature rise will be

Heat evolved in the first case : 40 x 5 - 200 cal.Heat evolved in the second case: 10 times of the first, that is, 10×200=2000 cal. ∴ 2000=400×ΔT or ΔT=5∘C.