Verified Solution • 2025–26 Session moderate

QJEEM24Ch17b3: JEE Main 2024 Chemistry - Class 12 JEEM24Ch17b3 Solution: Give below are two statements: One is labelled as Assertion A…

Give below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:

Assertion A: The stability order of +1 oxidation state of Ga, In and Tl is Ga < In < Tl.

Reason R: The inert pair effect stabilizes the lower oxidation state down the group.

In the light of the above statements, choose the correct answer from the options given below:

Multiple Choice Options

  • A A is true but R is false.
  • B Both A and R are true but R is NOT the correct explanation of A.
  • C A is false but R is true.
  • D Both A and R are true and R is the correct explanation of A.

Step-by-Step Verified Solution

To evaluate the statements provided, let's first understand the concepts involved:

Assertion A: The stability order of the +1 oxidation state of Ga, In, and Tl is Ga < In < Tl.

Reason R: The inert pair effect stabilizes the lower oxidation state down the group.

The elements Ga (Gallium), In (Indium), and Tl (Thallium) belong to Group 13 of the periodic table. As we move down this group, the +3 oxidation state becomes less stable while the +1 oxidation state becomes more stable. This trend is attributed to the inert pair effect.

The inert pair effect refers to the reluctance of the s-electrons to participate in bonding as we move down the group in the periodic table. For Group 13 elements, this effect causes the lower +1 oxidation state to be more stable compared to the +3 oxidation state down the group.

Given this, the Reason R correctly explains why the +1 oxidation state is more stable for Tl compared to Ga and In. Therefore, the stability order of the +1 oxidation state should indeed be Ga < In < Tl.

Conclusion: Both Assertion A and Reason R are true, and Reason R is the correct explanation for Assertion A.

Therefore, the correct answer is:

Option D: Both A and R are true and R is the correct explanation of A.

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