Question

During the melting of a slab of ice at $273 \,K$ at atmospheric pressure

• A. positive work is done by the ice-water system on the atmosphere
• B. positive work is done on the ice-water system by the atmosphere
• C. internal energy of ice-water system decreases
• D. none of the above

Answer 1

Answer: (B)

positive work is done on the ice-water system by the atmosphere

Answer 2

When a slab of ice at $273\,K$ melts, volume of water formed is less than the volume of ice melted ie, volume decreases. Therefore, work done by ice-water system is negative or in other words positive work is done by the atmosphere on the ice-water system. This increases the internal energy of ice-water system.