Question

Amongst the trihalides of nitrogen, which one is the least basic?

• A. ${\mathrm{NF}}_3$
• B. ${\mathrm{NCl}}_3$
• C. ${\mathrm{NBr}}_3$
• D. ${\mathrm{NI}}_3$

Answer 1

The correct option is A

${\mathrm{NF}}_3$

The explanation for the correct option:

A. ${\mathrm{NF}}_3$

Trihalides of Nitrogen:

• Trihalides of nitrogen are Lewis bases as the nitrogen atom has one unshared pair of electrons.
• Trihalides are unstable in nature due to the large size of halogens.
• The bonding between the nitrogen atom and halogen gets weaker due to the difference in electronegativity between atoms.

The trend for Trihalides of Nitrogen:

• Nitrogen trifluoride is the least basic in nature as fluorine has the highest electronegativity amongst halogens.
• Thus, the trend for the basicity in trihalides of nitrogen will be:

${\mathrm{NF}}_3<{\mathrm{NCl}}_3<{\mathrm{NBr}}_3<{\mathrm{NI}}_3$

The explanation for incorrect options:

Since, ${\mathrm{NF}}_3$ is the least basic in nature among all the trihalides of nitrogen. thus options B, C, and D stand incorrect.

Hence, the correct option is A.