(a) What are the criteria based on which refrigerant is chosen for refrigeration? Explain the absorption refrigeration with a flow diagram. Determine the expression of performance efficiency of an ideal absorption refrigeration cycle.

(b) What is the difference between Linde and Claude liquefaction processes?

(c) A rigid insulated tank of volume \(3 \mathrm{~m}^{3}\) is divided into two compartments by a removable partition of negligible volume. One compartment of volume \(1 \mathrm{~m}^{3}\) contains oxygen at \(500 \mathrm{~K}\) and 10 bar while second one contains nitrogen at \(800 \mathrm{~K}\) and 20 bar. The partition is removed and the gas is allowed to mix. After mixing, calculate the total change of entropy of the process. Assume both gases to be ideal with \(\gamma=1.4\).