Chemistry Q60 – JEE-MAIN 2025

Home Chemistry Periodicity & ElementsQuestion #540

The correct statements from the following are : (A)

T l^{3 +}

is a powerful oxidising agent (B)

A l^{3 +}

does not get reduced easily (C) Both

A l^{3 +}

and

T l^{3 +}

are very stable in solution (D)

T l^{+}

is more stable than

T l^{3 +}

(E)

A l^{3 +}

and

T l^{+}

are highly stable Choose the correct answer from the options given below :

Clue 1 of 3: Group 13 Elements

Consider the general trends in stability of oxidation states for Group 13 elements, especially the inert pair effect for heavier elements.

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Ninja Strategy•Inert Pair Effect First

Recognize that $T l^{3 +}$ is unstable and a strong oxidizing agent due to the inert pair effect. This immediately identifies statement (C) as incorrect, eliminating options 1 and 4, leaving only options 2 and 3 to compare.

🧠 Full Solution Path

Step 1: Analyze Stability of Oxidation States for Al and Tl✦ Active

For Aluminium (Al), the $+ 3$ oxidation state ( $A l^{3 +}$ ) is highly stable due to its small size and high charge density. The $+ 1$ oxidation state is highly unstable. For Thallium (Tl), due to the inert pair effect, the $+ 1$ oxidation state ( $T l^{+}$ ) is significantly more stable than the $+ 3$ oxidation state ( $T l^{3 +}$ ).

Step 2: Evaluate Oxidizing/Reducing Properties based on Stability○ Expand

Since $T l^{3 +}$ is less stable than $T l^{+}$ , $T l^{3 +}$ has a strong tendency to gain electrons and get reduced to $T l^{+}$ . This makes $T l^{3 +}$ a powerful oxidizing agent. Since $A l^{3 +}$ is very stable, it does not easily get reduced to lower oxidation states.

Step 3: Verify Each Statement○ Expand

Based on the stability analysis: (A) $T l^{3 +}$ is a powerful oxidising agent - Correct. (B) $A l^{3 +}$ does not get reduced easily - Correct. (C) Both $A l^{3 +}$ and $T l^{3 +}$ are very stable in solution - Incorrect ( $T l^{3 +}$ is unstable). (D) $T l^{+}$ is more stable than $T l^{3 +}$ - Correct. (E) $A l^{3 +}$ and $T l^{+}$ are highly stable - Correct. The correct combination of statements is (A), (B), (D), and (E).

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Chemistry Question 60 – JEE-MAIN 2025

Clue 1 of 3: Group 13 Elements

🧠 Full Solution Path