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Chemical Bonding and Molecular Structure

Multiple Choice Questions

601.

dsp² hybridisation is found in

[Ni(CN)₄]^2-
[CoCl₄]^2-
[CuCl₄]^3-
[CuCl₄]^2-

602.

Cold ferrous sulphate solution on absorption of NO develops brown colour due to the formation of

paramagnetic [Fe(H₂O)₅(NO)] SO₄
diamagnetic [Fe(H₂O)₅(N₃)] SO₄
paramagnetic [Fe(H₂O)₅(NO₃)][SO₄]₂
diamagnetic [Fe(H₂O)₄ (SO₄)]NO₃

603.
Which of the following option w.r.t. increasing bond order is correct ?

NO < C₂<O₂^-<He₂⁺

C₂< NO < He₂⁺< O₂^-

He₂⁺< O₂^-< NO < C₂

He₂⁺< O₂^-< C₂< NO.

He₂⁺< O₂^-< C₂< NO.

Bond Order of the molecules:

O₂^-; $KK (σ 2 s)^{2} (σ^{*} 2 s)^{2} (σ 2 p_{z})^{2} (π 2 p_{x})^{2} (π 2 p_{y})^{2} (π^{*} 2 p_{x})^{2} (π^{*} 2 p_{y})^{1}$

Bond order of O₂^-= $\frac{1}{8} - (8 - 5) = 1.5$

He₂⁺: $(σ 1 s)^{2} (σ^{*} 1 s)^{1}$

Bond order of He₂⁺= $\frac{1}{2} (2 - 1) = 0.5$

$C_{2} : KK (σ 2 s)^{2} (σ^{*} 2 s)^{2} (σ 2 p_{z})^{2} (π 2^{2} p_{x})^{2} (π 2^{2} p_{y}) (π^{*} 2 p_{x})^{1} Bond order = \frac{1}{2} (6 - 2) = 2.0 NO : KK (σ 2 s)^{2} (σ^{*} 2 s)^{2} (σ 2 p_{z})^{2} (π 2^{2} p_{x})^{2} (π 2^{2} p_{y})^{2} (π^{*} 2 p_{x})^{1} Bond order = \frac{1}{2} (8 - 3) = 2.5$

604.

The BCl₃, is a planar molecule where as NCl₃, is pyramidal. because

B-Cl bond is more polar than N-Cl bond
N-Cl bond is more covalent than B-Cl bond
nitrogen atom is smaller than boron atoms
BCl₃ has no lone pair but NCl₃ has a lone pair of electrons.

605.

The electronic configuration is 1s² 2s² 2p⁵ 3s¹ shows

ground state of fluorine atom
excited state of fluorine atom
excited state of neon atom
excited state of ion O₂

606.

Assertion : B₂H₆, Si₂H₆, are said to have similar structure.

Reason : They have same number of $σ$ and $π$ bonds.

If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
If Assertion is true but Reason is false.
If Assertion is false but Reason is true.

607.

Assertion: Sigma ( $σ$ ) is a strong bond, while pi ( $π$ ) is a weak bond.
Reason: Atoms rotate freely about the pi ( $π$ ) bond.

If both assertion and reason are true and the reason is a correct explanation of the assertion.
If both the assertion and reason are true but the reason is not a correct explanation of the assertion.
If the assertion is true but the reason is false.
If both the assertion and reason are false.