PHYSICS · Single correct · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
A 10 g sample of naphthalene (m.p. ≈ 80 °C) undergoes the following three consecutive steps at 1 atm:
1. The solid is heated from 60 °C to 80 °C.
2. The solid melts completely at 80 °C.
3. The resulting liquid is cooled from 80 °C to 70 °C.
Which row correctly identifies each step as endothermic (E) or exothermic (X)?
(a) Step1−EStep2−XStep3−X
(b) Step1−EStep2−EStep3−E
(c) Step1−EStep2−EStep3−X
(d) Step1−XStep2−EStep3−X