Question

Assertion : The normal boiling point of water is $100{}^{\circ }C$ and standard boiling point of water is $99.6{}^{\circ }C$.
Reason: The temperature at which vapour pressure of liquid is equal to the external pressure is called boiling temperature at that pressure.

• A. If both assertion and reason are true and reason is the correct explanation of assertion.
• B. If both assertion and reason are true but reason is not the correct explanation of assertion.
• C. If assertion is true but reason is false.
• D. If both assertion and reason are false.

Answer 1

Answer: (B)

At $1$ atm pressure, boiling temperature is called normal boiling point and if pressure is $1$ bar then the boiling point is called standard boiling point of the liquid. $1$ bar pressure is slightly less than $1$ atm pressure therefore, standard boiling point of the liquid is slightly lower than the normal boiling point.