A test tube containing liquid naphthalene is cooling and solidifying (freezing) at its melting point of 80∘C80^\circ\text{C}80∘C. Nearby, a beaker of pure water is boiling vigorously on a hot plate. Both are in a laboratory at 20∘C20^\circ\text{C}20∘C.
What is happening to the temperature of the solidifying naphthalene and what is happening to the temperature of the boiling water?
Temperature of naphthalene: constant; temperature of water: constant
Temperature of naphthalene: constant; temperature of water: increasing
Temperature of naphthalene: decreasing; temperature of water: constant
Temperature of naphthalene: decreasing; temperature of water: increasing
313 exam-style questions on CIE IGCSE Physics 2.2.3a Melting, boiling, condensation and solidification. Each one has a worked solution and a mark scheme showing where the marks go.