These questions consist two statements each, printed as Assertion and reason, while answering these question you are required to choose any one of the following four responsis:
(a) If both the assertion and reason are true and reason is a true explanation of the assertion.
(b) If both the assertion and reason are true but the reason is not the correct explanation of assertion.
(c ) If the assertion is true but reason is false.
(d) If both the assertion and reason are false.
Q. Assertion: in a pressure cooker the water is brought to boil. The cooker is then removed from the stove. Now on removing the lid of the pressure cooker, the water starts boiling again.
Reason: The impurities in water bring down its boiling point.

Answer

C

Explanation

We know that the boiling point of liquid increases with increase of vapour pressure. In a cooker water with the food to be cooked. Is heated, such that confined water vapours raise the superincumbent pressure. As a result, water boils at the temperature higher than boiling point `100^@C`. Now when the cooker removed from the stove and its lid is also removed, pressure decreases due to which its boiling point comes down but it is still at `100^@C` so , water again begins to boil. When we add small impurities in water the boiling point is not affected and remains same.