Question

: Which of the following statements regarding ${N_2}{O_4}$ is not correct?
A.The molecule of ${N_2}{O_4}$ is planer.
B.The molecule of ${N_2}{O_4}$ contains weak $N - N$ bond
C.In liquid ${N_2}{O_4}$, $NOCl$ acts as a base
D.The dipole moment of ${N_2}{O_4}$ is zero.

Answer 1

To solve this question, it is required to have knowledge about the oxides of nitrogen. ${N_2}{O_4}$ is dinitrogen tetroxide or nitrogen tetroxide is also called ‘amyl’ by Russian rocket engineers. It is a self ionizing aprotic solvent.

Complete step by step answer:
Dinitrogen tetroxide could be regarded as two nitro groups bonded together $\left( {N{O_2}} \right)$. The molecule is planar with a $N - N$ bond distance of $1.78$ Å and N-O bond distance of $1.19$ Å. Hence, the first statement is correct.
The long bond length of the $N - N$ bond in ${N_2}{O_4}$ corresponds to a weaker bond because the normal $N - N$ bond length of $1.45$ Å. Hence, this is also correct.
${N_2}{O_4}$ is a self-ionizing aprotic solvent that undergoes ionization as follows:
${N_2}{O_4} \rightleftharpoons {\left[ {NO} \right]^ + } + \left[ {N{O_3}^ - } \right]$
In this solution nitrosyl salts behave as an acid and metal nitrates behave as bases. Now,$NOCl$ contains the nitrosyl group as this is nitrosyl chloride and hence this should act as an acid, not a base. Hence, this statement is incorrect.
The dipole moment of ${N_2}{O_4}$ has a small value that is close to zero. So, this statement is also correct.

So, the correct answer to the above question is option C.

Note:
Nitrogen Tetroxide is used as an oxidiser in rocket propellants because it can be stored as a liquid at room temperature. It behaves as a salt in the synthesis of metal nitrates and a range of metal nitrates with diverse transition metals can be formed in it.