With increase in molecular weight of the gas, the head developed by a centrifugal compressor will

Answer: Option A

The head developed by a centrifugal compressor is dependent on the kinetic energy imparted to the gas. The kinetic energy is directly related to the velocity of the gas molecules. With an increase in molecular weight of the gas, the average velocity of the gas molecules decreases due to higher mass. This results in a decrease in kinetic energy and consequently, a decrease in the head developed by the centrifugal compressor.
Hence, the correct answer is Option A: Decrease.