Question

Alka was making tea in a kettle. Suddenly she felt intense heat from the puff of steam gushing out of the spout of the kettle. She wondered whether the temperature of the steam was higher than that of the water boiling in the kettle. Comment.

Answer 1

Hint:Here we have to use the concept of latent heat and boiling point of water.
Latent heat is described as the heat or energy that during a phase change of a material is absorbed or emitted. That may be from gas to liquid or from liquid to solid and vice versa.

Complete step by step solution:
Specific latent heat is associated with changes in phase, such as when water evaporates or boils, it transforms into a gas from a liquid, or as ice melts, water turns into a liquid from a solid. To melt ice, or to boil liquid water over and above the heat needed to raise the temperature of the water, extra energy is required. When liquid water freezes, or when steam condenses to form liquid water, almost the same amount of energy is released.

Water has a very high latent vaporisation heat-at the boiling point of water, it requires around $2200$ joules of heat energy to get one gram of water to move from liquid to gas. The latent fusion heat of water is about seven times smaller-it requires about $330$ joules of heat energy to transform one gram of ice at the melting point of water into one gram of liquid water.

The water’s boiling point is ${100^ \circ }C$.

Instead of a constant supply of heat, the temperature of boiling water does not increase, since the added heat provided to the water is used to transform water into steam. Therefore, steam has a lot of latent heat that can cause extreme burns. This is why Alka felt intense heat gushing out of the spout of the kettle from the puff of steam.

Note:
In short we can say that the transformations from one form to another the latent heat is released. So steam becomes hotter than water.