Chemical Bonding and Molecular Structure Chapter-Wise Test 1

Correct answer Carries: 4.

Wrong Answer Carries: -1.

The bond order of \( \ce{NO^+} \) ion, considering its molecular orbital configuration, is:

For \( \ce{NO^+} \) (14 electrons - 1 = 13): \( (\sigma 1s)^2 (\sigma^* 1s)^2 (\sigma 2s)^2 (\sigma^* 2s)^2 (\pi 2p_x)^2 (\pi 2p_y)^2 (\sigma 2p_z)^2 \). Bonding = 10, antibonding = 4. Bond order = \( \frac{10 - 4}{2} = 3 \).

3
2.5
2
1.5
1

The number of lone pairs on bromine in \(\ce{BrF3}\) is:

In \(\ce{BrF3}\), bromine has 7 valence electrons and forms 3 single bonds (6 electrons used), leaving 4 electrons as 2 lone pairs. With \(sp^3d\) hybridization, the 5 electron pairs (3 bonding, 2 lone) result in a T-shaped molecular geometry.

1
3
2
0
3

The bond angle in \( \ce{H2S} \) is approximately:

In \( \ce{H2S} \), sulfur is \( sp^3 \) hybridized with two lone pairs, reducing the bond angle to about 92° due to lone pair repulsion.

109.5°
107°
104.5°
92°
4

The bond in \( \ce{HCl} \) is an example of:

In \( \ce{HCl} \), hydrogen and chlorine share one electron pair, forming a single covalent bond.

Single covalent bond
Double covalent bond
Ionic bond
Coordinate bond
1

Which molecule has an equatorial bond angle of approximately 101° due to a lone pair?

In \(\ce{SF4}\), sulfur is \(sp^3d\) hybridized with 5 electron pairs (4 bonding, 1 lone), forming a see-saw shape. The equatorial F-S-F bond angle is ~101° due to lone pair repulsion compressing the equatorial bonds.

\(\ce{PF5}\)
\(\ce{SF4}\)
\(\ce{ClF3}\)
\(\ce{XeF4}\)
2

The number of sigma bonds in \( \ce{C3H6} \) (cyclopropane) is:

In \( \ce{C3H6} \) (cyclopropane), there are 3 \( \ce{C-C} \) sigma bonds in the ring and 6 \( \ce{C-H} \) sigma bonds, totaling 9 sigma bonds.

8
10
7
9
4

Which molecule has a linear geometry due to \( sp \) hybridization?

In \( \ce{C2H2} \), each carbon is \( sp \) hybridized, forming a triple bond and a linear structure with a 180° bond angle.

\( \ce{H2O} \)
\( \ce{NH3} \)
\( \ce{C2H2} \)
\( \ce{BF3} \)
3

Which molecule has a trigonal planar electron pair geometry and a trigonal planar molecular shape?

In \( \ce{BCl3} \), boron has 3 bonding pairs and no lone pairs with \( sp^2 \) hybridization, giving a trigonal planar electron and molecular geometry.

\( \ce{BCl3} \)
\( \ce{SO2} \)
\( \ce{NH3} \)
\( \ce{H2O} \)
1

Which molecule has an incomplete octet with only 6 electrons around the central atom?

In \( \ce{AlCl3} \), aluminum forms three bonds, using 6 electrons, resulting in an incomplete octet.

\( \ce{NH3} \)
\( \ce{PCl5} \)
\( \ce{CH4} \)
\( \ce{AlCl3} \)
4

The total number of sigma bonds in \( \ce{C6H6} \) (benzene) is:

In \( \ce{C6H6} \) (benzene), there are 6 \( \ce{C-C} \) sigma bonds in the ring, 6 \( \ce{C-H} \) sigma bonds, totaling 12 sigma bonds (plus 3 pi bonds).

13
12
15
11
2

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