Inert Pair Effect & Stability — Tl⁺ vs Tl³⁺ and Al³⁺ Explained

❓ Question

Which of the following statements are correct?

(A) Tl³⁺ is a powerful oxidising agent
(B) Al³⁺ does not get reduced easily
(C) Both Al³⁺ and Tl³⁺ are very stable in solution
(D) Tl⁺ is more stable than Tl³⁺
(E) Al³⁺ and Tl⁺ are highly stable

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🖼️ Question Image

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✍️ Short Explanation

This problem is based on:

👉 Inert pair effect
👉 Stability of oxidation states
👉 Oxidising nature.

Main idea:

Down group 13:

$$+1 \text{ oxidation state becomes more stable}$$

due to inert pair effect.

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🔷 Step 1 — Check Statement (A) 💯

$$Tl^{3+}$$

is unstable and prefers converting into:

$$Tl^+$$

Thus:

$$Tl^{3+}\rightarrow Tl^+$$

This means $Tl^{3+}$ easily gets reduced.

Hence it acts as:

$$\boxed{ \text{Strong oxidising agent} }$$

✔ (A) Correct.

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🔷 Step 2 — Check Statement (B)

$$Al^{3+}$$

is very stable because aluminum strongly prefers:

$$+3$$

oxidation state.

Thus it does not reduce easily.

✔ (B) Correct.

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🔷 Step 3 — Check Statement (C)

$$Tl^{3+}$$

is NOT very stable in solution.

It tends to convert into:

$$Tl^+$$

Hence statement (C) is false.

❌ Incorrect.

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🔷 Step 4 — Check Statement (D)

Due to inert pair effect:

$$Tl^+$$

is more stable than:

$$Tl^{3+}$$

✔ Correct.

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🔷 Step 5 — Check Statement (E)

Most stable oxidation states:

$$Al^{3+}$$

and

$$Tl^+$$

✔ Highly stable.

Thus (E) is correct.

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🔷 Step 6 — Final Correct Statements

Correct:

$$(A),\ (B),\ (D),\ (E)$$

Incorrect:

$$(C)$$

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🔷 Step 7 — JEE Trap Alert 🚨

❌ Inert pair effect ignore kar dena

❌ $Tl^{3+}$ ko stable maan lena

Remember:

Down the group:

$$\boxed{ +1 \text{ state stability increases} }$$

especially for Tl.

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✅ Final Answer

$$\boxed{{\displaystyle (A),(B),(D)\text{ and }(E)\text{ only}}}$$

(Option 3)

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