Chemical Bonding and Molecular Structure Chapter-Wise Test 9

Correct answer Carries: 4.

Wrong Answer Carries: -1.

The bond length of a \( \ce{C=C} \) double bond is approximately:

The average bond length of a \( \ce{C=C} \) double bond, as in ethene, is ~134 pm due to increased electron density from two shared pairs, shorter than a \( \ce{C-C} \) single bond (~154 pm) but longer than a \( \ce{C#C} \) triple bond (~120 pm).

154 pm
134 pm
120 pm
109 pm
2

The bond angle in \( \ce{XeF2} \) is:

In \( \ce{XeF2} \), xenon is \( sp^3d \) hybridized with 5 electron pairs (2 bonding, 3 lone), resulting in a linear shape with a 180° bond angle.

109.5°
120°
90°
180°
4

Which molecule has a bond angle of approximately 90° due to lone pair repulsion in a square pyramidal geometry?

In \( \ce{BrF5} \), bromine is \( sp^3d^2 \) hybridized with 6 electron pairs (5 bonding, 1 lone), forming a square pyramidal shape with ~90° bond angles.

\( \ce{SF6} \)
\( \ce{BrF5} \)
\( \ce{XeF4} \)
\( \ce{PF5} \)
2

The bond order of \( \ce{C2^+} \) ion, based on molecular orbital theory, is:

For \( \ce{C2^+} \) (11 electrons): \( (\sigma 1s)^2 (\sigma^* 1s)^2 (\sigma 2s)^2 (\sigma^* 2s)^2 (\pi 2p_x)^2 (\pi 2p_y)^1 \). Bonding = 7, antibonding = 4. Bond order = \( \frac{7 - 4}{2} = 1.5 \).

1.5
2
2.5
1
1

The hybridization of xenon in \( \ce{XeF6} \) is:

In \( \ce{XeF6} \), xenon has 8 valence electrons, forms 6 bonds (12 electrons used), leaving 2 electrons as 1 lone pair. With 7 electron pairs (6 bonding, 1 lone), it adopts \( sp^3d^2 \) hybridization, forming an octahedral electron geometry with a distorted octahedral molecular shape due to lone pair repulsion.

\( sp^3d \)
\( sp^3d^3 \)
\( sp^3d^2 \)
\( sp^3 \)
3

Which molecule has a trigonal bipyramidal electron pair geometry but a linear molecular shape?

In \( \ce{XeF2} \), xenon has 5 electron pairs (2 bonding, 3 lone) with \( sp^3d \) hybridization, giving a trigonal bipyramidal electron geometry and a linear shape.

\( \ce{XeF2} \)
\( \ce{SF4} \)
\( \ce{PF5} \)
\( \ce{ClF3} \)
1

Which molecule contains a coordinate bond where oxygen donates a lone pair to a positively charged species?

In \( \ce{H3O^+} \) (hydronium ion), oxygen donates a lone pair to \( \ce{H^+} \), forming a coordinate bond.

\( \ce{H3O^+} \)
\( \ce{NH3} \)
\( \ce{CH4} \)
\( \ce{CO2} \)
1

Which species has a bond order of 1 and is paramagnetic?

For \( \ce{B2} \): \( (\sigma 1s)^2 (\sigma^* 1s)^2 (\sigma 2s)^2 (\sigma^* 2s)^2 (\pi 2p_x)^1 (\pi 2p_y)^1 \). Bonding = 6, antibonding = 4. Bond order = \( \frac{6 - 4}{2} = 1 \), with 2 unpaired electrons (paramagnetic).

\( \ce{Li2} \)
\( \ce{B2} \)
\( \ce{F2} \)
\( \ce{N2} \)
2

Which of the following molecules exhibits \( sp^3d \) hybridization?

In \( \ce{AsF5} \), arsenic uses one s, three p, and one d orbital to form five \( sp^3d \) hybrid orbitals, giving a trigonal bipyramidal shape.

\( \ce{SF6} \)
\( \ce{AsF5} \)
\( \ce{BCl3} \)
\( \ce{CH4} \)
2

What is the bond angle in a molecule with a trigonal planar geometry?

In trigonal planar geometry, such as in \( \ce{BCl3} \), the bond angle is 120° due to three bonding pairs arranged symmetrically.

120°
109.5°
180°
90°
1

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