Question

Why are the inner lining of hot water geysers made up of copper?
A. Copper has low heat capacity
B. Copper has high electric conductivity
C. Copper does not react with steam
D. None of the above

Answer 1

Hint: In a geyser the main objective is to make sure the water remains hot for a longer time, but another thing that has be kept assured of is that the hot water should not damage the geysers, as usage of hot water over a metal for quite a long time can corrode the metal leading the damage of the geyser.

Complete answer:
Since in a geyser our main objective is to keep the hot water hot for quite a long time a special arrangement is made for the container.In the figure given below we have insulation on the outermost layer, then the inner lining is made of copper. Copper is shown in a pale golden colour, the insulation is shown in black and the water stored is in blue.

Copper being a very low reactive metal doesn’t react with water (even in steam form). So, a copper lining is given so that the hot water doesn’t get in contact with any of the other parts of the geyser ensuring its long life.

Hence, correct answer is option C.

Note: Even though copper metal is a very good conductor of heat (has very low heat capacity), the heat loss is prevented by the proper insulation outside the copper lining. Apart from copper, stainless steel is also used as a lining material. Nowadays the most used material is a special type of stainless plastic polymer that has high heat capacity and is non-reactive to water.