The p-Block Elements NEET PYQ | Previous Year Questions with Solutions

Q 1 :

Taking stability as the factor, which one of the following represents correct relationship? [2023]

$AlCl > {AlCl}_{3}$
$TlI > {TlI}_{3}$
${TlCl}_{3} > TlCl$
${InI}_{3} > InI$

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(2)

As we move down the group, the stability of the +3 oxidation state decreases while that of +1 oxidation state increases. Thus, stability order for +1 oxidation state is $Al < Ga < In < Tl$ and +3 oxidation state is $Al > Ga > In > Tl$ .

Hence, the stability order is, ${AlCl}_{3} > AlCl, TlI > {TlI}_{3}, TlCl > {TlCl}_{3}$ and $InI > {InI}_{3}$ .

Q 2 :

${BF}_{3}$ is planar and electron deficient compound. Hybridization and number of electrons around the central atom, respectively are [2021]

$s p^{2}$ and 8
$s p^{3}$ and 4
$s p^{3}$ and 6
$s p^{2}$ and 6

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(4)

${BF}_{3}$ is a $s p^{2}$ -hybridised planar molecule. It forms $3 σ$ -bonds with 3F-atoms, hence has six electrons around it.

Q 3 :

The correct order of atomic radii in group 13 elements is [2018]

$B < Al < In < Ga < Tl$
$B < Al < Ga < In < Tl$
$B < Ga < Al < Tl < In$
$B < Ga < Al < In < Tl$

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(4)

Q 4 :

The stability of +1 oxidation state among $Al$ , Ga, $In$ and $Tl$ increases in the sequence [2015, 2009]

$Al < Ga < In < Tl$
$Tl < In < Ga < Al$
$In < Tl < Ga < Al$
$Ga < In < Al < Tl$

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(1)

In group 13 elements, stability of +3 oxidation state decreases down the group while that of +1 oxidation state increases due to inert pair effect. Hence, stability of +1 oxidation state increases in the sequence: $Al < Ga < In < Tl$ .

Q 5 :

Which of the following statement is not correct about diborane? [2022]

Both the Boron atoms are $s p^{2}$ hybridised.
There are two 3-centre-2-electron bonds.
The four terminal B–H bonds are two-centre two-electron bonds.
The four terminal hydrogen atoms and the two boron atoms lie in one plane.

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Q 6 :

Which of the following statement is not correct about diborane? [2022]

Both the Boron atoms are $s p ²$ hybridised.
There are two 3-centre-2-electron bonds.
The four terminal B-H bonds are two centre two electron bonds.
The four terminal Hydrogen atoms and the two Boron atoms lie in one plane.

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