JEE Chemistry 2023 Question with Solution

Given: The species are $\text{XeF}_4$, $\text{SF}_4$, $\text{SiF}_4$, $\text{BF}_4$, $\text{BrF}_4^-$, $[\text{Cu}(\text{NH}_3)_4]^{2+}$, $[\text{FeCl}_4]^{2-}$ and $[\text{PtCl}_4]^{2-}$.

Find: The number of species having square planar shape.

Square planar geometry arises either from an octahedral electron pair arrangement with two lone pairs in opposite positions, or in some coordination compounds of suitable metal ions.

From the solution:

• $\text{XeF}_4$ has $4$ bond pairs and $2$ lone pairs, so it is square planar.
• $\text{SF}_4$ has $1$ lone pair in trigonal bipyramidal arrangement, so it is see-saw.
• $\text{SiF}_4$ is tetrahedral.
• $\text{BrF}_4^-$ has $4$ bond pairs and $2$ lone pairs, so it is square planar.
• $[\text{Cu}(\text{NH}_3)_4]^{2+}$ is counted as square planar in this question.
• $[\text{FeCl}_4]^{2-}$ is tetrahedral.
• $[\text{PtCl}_4]^{2-}$ is square planar.

Therefore, the square planar species are:

$$\text{XeF}_4,\ \text{BrF}_4^-,\ [\text{Cu}(\text{NH}_3)_4]^{2+},\ [\text{PtCl}_4]^{2-}$$

Hence, the total number of such species is $4$.

Therefore, the answer is $4$.

Given: The listed species must be checked for square planar geometry.

Find: How many are square planar.

A quick scan from the extracted solution shows:

$$\text{XeF}_4,\ \text{BrF}_4^-,\ [\text{Cu}(\text{NH}_3)_4]^{2+},\ [\text{PtCl}_4]^{2-}$$

are square planar, while the others are not.

So the count is $4$.

Therefore, the answer is $4$.