Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Lithium salts are hydrated.
Reason (R) : Lithium has higher polarising power than other alkali metal group members.
In the light of the above statements, choose the most appropriate answer from the options given below :
Assertion (A) : Lithium salts are hydrated.
Reason (R) : Lithium has higher polarising power than other alkali metal group members.
In the light of the above statements, choose the most appropriate answer from the options given below :
- (A)Both (A) and (R) are correct and (R) is the correct explanation of (A).✓ Correct
- (B)(A) is correct but (R) is not correct .
- (C)(A) is not correct but (R) is correct.
- (D)Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
Answer: (A)
Solution
Lithium salts such as are commonly hydrated, so the assertion is correct. The lithium ion is the smallest alkali metal cation and has the highest charge density, giving it the greatest polarising power in the group, so the reason is also correct. This high charge density allows to bind water strongly through ion-dipole attraction, which is why its salts crystallise as hydrates, so the reason correctly explains the assertion. Both the assertion and the reason are correct and the reason is the correct explanation of the assertion.
JEE Main · 2021 · 31 Aug 2021 · Shift 2 · Single correct option