Question

The correct statements from the following are:
(A) The decreasing order of atomic radii of group 13 elements is Tl $>$ In $>$ Ga $>$ Al $>$ B.
(B) Down the group 13 electronegativity decreases from top to bottom.
(C) Al dissolves in dil. HCl and liberate H$_2$, but conc. HNO$_3$ renders Al passive by forming a protective oxide layer on the surface.
(D) All elements of group 13 exhibits highly stable +1 oxidation state.
(E) Hybridisation of Al in [Al(H$_2$O)$_6$]$^{3+}$ ion is sp$^3$d$^2$.
Choose the correct answer from the options given below.

• A. (C) and (E) only
• B. (A), (C) and (E) only
• C. (A), (B), (C) and (E) only
• D. (A) and (C) only

Answer 1

Answer: (A)

(C) and (E) only

Answer 2

Step 1: Analyze each statement
Statement (A):
The correct order of atomic radii in group 13 elements is $\text{Tl} > \text{In} > \text{Al} > \text{Ga} > \text{B}$, not $\text{Tl} > \text{In} > \text{Ga} > \text{Al} > \text{B}$.
- This statement is incorrect.
2.Statement (B):
Down the group, electronegativity generally decreases. However, due to the presence of $d$-electrons in $\text{Ga}$, $\text{In}$, and $\text{Tl}$, their electronegativity values do not follow a simple trend.
- This statement is incorrect.
3.Statement (C):
$\text{Al}$ reacts with dilute $\text{HCl}$ to release $\text{H}_2$:
$2\text{Al} + 6\text{HCl} \rightarrow 2\text{AlCl}_3 + 3\text{H}_2.$
Concentrated $\text{HNO}_3$ forms a passive oxide layer on $\text{Al}$, protecting it from further reaction.
- This statement is correct.
4.Statement (D):
In group 13, the $+3$ oxidation state is more stable than $+1$. The $+1$ state is exhibited by $\text{Tl}$ due to the inert pair effect, but it is
not highly stable for all elements.
- This statement is incorrect.
5.Statement (E):
In $[\text{Al}(\text{H}_2\text{O})_6]^{3+}$, the hybridization of $\text{Al}$ is $\text{sp}^3\text{d}^2$, corresponding to an octahedral geometry. - This statement is correct.
Step 2: Conclusion
The correct statements are (C) and (E).
Final Answer: (1).