Which of the following reasons explains why if salt water is heated, the water turns into steam while the salt remains?

a. water and salt have an equal boiling point.
b. water has a lower boiling point than salt.
c. salt has a lower boiling point than water.
d. salt and water have an equal melting point.

The correct answer is (b) The water has a lower boiling point than salt.

The separation of salt from water is carried out by the process of distillation. The boiling point of water is lower than that of salt so the water converts into steam on heating and the salt remains in the vessel. When salt is mixed in water, there occurs a phenomenon called elevation in boiling point of water but the change is very less as it cannot be observed. Even if there is a elevation in boiling point of the water it is lower as compared to the boiling point of salt.

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