Paper: CSIR-NET June 2018 · Subject: Physical Chemistry · Chapter: Thermodynamics · Topic: Laws State Functions · Marks: 2 · Difficulty: Medium
In the phase diagram of water, the solid-liquidboundary has a negative slope. The reason for this unusual behavior can be traced to decrease in
(a)Density of the system on melting
(b)volume of the system on melting
(c)entropy of the system on melting
(d)enthalpy of the system on melting
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
Clapeyron: dp/dT = ΔS_fus/ΔV_fus. For water ΔV_fus < 0 (ice is less dense than water, the volume decreases on melting) while ΔS_fus > 0, so the slope is negative.