NEETChemistrySolutions
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : The dissolution of a gas in a liquid is an exothermic process. Reason (R) : The value of Henry's law constant ( K_H ) for a gas in a liquid increases with an increase in temperature. In the light of the above statements, choose the most appropriate answer from the options given below :
Options
- ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- BBoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- CAssertion (A) is true but Reason (R) is false.
- DAssertion (A) is false but Reason (R) is true.
Correct answer
B. Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
Step-by-step solution
Assertion (A) is true because the dissolution of a gas in a liquid involves a decrease in entropy and is generally an exothermic process ( H Reason (R) is also true. According to Le Chatelier's principle, since the dissolution is exothermic, solubility decreases with an increase in temperature. From Henry's law ( p = K_H x ), for a given pressure, a decrease in solubility ( x ) means the Henry's law constant ( K_H ) must increase. Thus, K_H increases with temperature. However, Reason (R) is a consequence of Asserti