Question

Which of the statements are incorrect about the following compound?

• A. All three C-N bonds are of same length
• B. $C_1-N$ and $C_3-N$ bonds are of same length but shorter than $C_5-N$ bond
• C. $C_1-N$ and $C_5-N$ bonds are of same lengths but longer than $C_3-N$ bond
• D. $C_1-N$ and $C_3-N$ bonds are of different length but both are longer than $C_5-N$ bond

Answer 1

The correct option is A All three C-N bonds are of same length

By rotating the molecule one hundred eighty degrees about the $C^2$ symmetry axis that passes through the bromide and the nitro group in the $5$-possition$.$ If we interconvert $C_1-N{O}_2$ and $C_{2}N{O}_2.$ Groups that can be interconnected by a rotational axis must be equivalent$.$ There is no symmetry element cannot be equivalent$.$ So$,$ symmetry tells us that the $C_1-N{O}_2$ and $C_{2}N{O}_2$ bond lengths are exactly the same$,$ and both are different from the $C_5-N{O}_2$ bond length$.$