2019:
The correct answer is (A). The C-C bond length in benzene is 1.39 Å, which is shorter than the C-C bond length in ethane (1.54 Å). This is because the pi electrons in benzene delocalize over the entire ring, which results in a decrease in the electron density between the carbon atoms and an increase in the bond strength.
2018:
The correct answer is (B). The N-O bond length in NO2 is 1.19 Å, which is shorter than the N-O bond length in NO (1.15 Å). This is because the presence of the second oxygen atom in NO2 pulls electron density away from the nitrogen atom, which results in a decrease in the bond length.
2017:
The correct answer is (A). The C-O bond length in CO2 is 1.16 Å, which is shorter than the C-O bond length in CO (1.12 Å). This is because the presence of the second oxygen atom in CO2 pulls electron density away from the carbon atom, which results in a decrease in the bond length
