The following table of properties was printed out for saturated liquid and saturated vapor of ammonia. The titles for only the first two columns are available. All that we know is that the other columns (columns 3 to 8) contain data on specific properties, namely, internal energy (kJ/kg), enthalpy (kJ/kg), and entropy (kJ/kg.K). The specific enthalpy data are in columns

A. 3 and 7 B. 3 and 8 C. 5 and 7 D. 5 and 8

When saturated liquid at 40 C is throttled to −20 C, the quality at exit will be ______ A. 0.189 B. 0.212 C. 0.231 D. 0.788

Answer: We know that enthalpy is always slightly greater than internal energy.

h = u + pv

where pv is flow work, the fluid has to overcome at the inlet and exit of the control volume.

In the steam tables, enthalpy columns have the largest values. Hence

**Hence column first question the answer is D.**

**Therefore the answer is B**