Question

Assertion: In a pressure cooker the water is brought to boil. The cooker is then remove from the stove. Now on removing the lid of the pressure cooker, the water starts boiling against.

Reason: The impurities in water bring down its boiling point

A. If both assertion and reason are true but the reason is the correct explanation of assertation

B. If both assertation and reason are true but the reason is not correct explanation of assertation

C. If assertation is true but the reason is false

D. If both the assertion and reason are false

E. If reason is true but assertion is false

Answer 1

The assertion that releasing the lid of a pressure cooker causes the water to boil again is true; however, the reason given is false. Impurities in water have a minimal effect on boiling point in this context. The real reason water boils upon lid removal is due to the abrupt drop in pressure within the cooker.

Step-by-step explanation:

In the scenario described, upon removing the pressure cooker lid after boiling water and then taking it off the stove, the water begins to boil again due to the sudden decrease in pressure. However, the reason provided is incorrect. The impurities in water do not bring down its boiling point sufficiently to cause this effect. Instead, the boiling point of water increases with pressure, and vice versa. In a pressure cooker, water can boil above the normal boiling point due to increased pressure. When the lid is removed, pressure rapidly drops, making the boiling point of the water inside the cooker lower than the water's current temperature, leading to immediate boiling.

Pressure cookers work by sealing the steam inside, which raises the internal pressure and thus the boiling point of water. This process allows food to cook at higher temperatures, thus reducing cooking times. The principle behind this relates to the vapor pressure of liquids and the relationship between pressure and the boiling point.