Question

In solvents like$DMSO$, acetonitrile, ${{F}^{-}}$ ion of dissolved $NaF$ is more reactive than in methyl alcohol. Explain
A. $C{{H}_{3}}OH$ is more polar than $DMSO$ and $C{{H}_{3}}CN$
B. $C{{H}_{3}}OH$ is less polar than $DMSO$ and $C{{H}_{3}}CN$
C. Unsolved ${{F}^{-}}$ ion is $DMSO$ or $C{{H}_{3}}CN$ acts more effectively as nucleophile
D. $-OH$ group is better leaving group than ${{F}^{-}}$ ion

Answer 1

Hint: In the methyl alcohol ${{F}^{-}}$ion is solvated whereas in the solvents like $DMSO$ and acetonitrile this ${{F}^{-}}$ion of dissolved $NaF$is not solvated. Analyze the above line and find the activity of the${{F}^{-}}$ion in both the cases and find out the correct explanation from the given above options.

Complete step by step answer:
 We know that when we try to dissolve the compound $NaF$ in methyl alcohol the dissolved ${{F}^{-}}$ ions are get solvated in it, that is the ${{F}^{-}}$ ions are get solvated in methyl alcohol whereas in case of the solvents like $DMSO$ and acetonitrile these ${{F}^{-}}$ ion of dissolved $NaF$ are not solvated and so these ions are free in the solvent. Due to the presence of the free ${{F}^{-}}$ ions in the solvent which are not solvated, these act as more efficiently as nucleophiles.
A nucleophile is a chemical species that donates an electron pair to form a chemical bond in a reaction to reaction. All molecules or ions with a free pair of electrons or at least one \[\pi \] bond can act as nucleophiles. Because nucleophiles donate electrons, they are by definition Lewis bases.

Since we found that the unsolvated ${{F}^{-}}$ ions more efficiently act as a nucleophile and hence option (C) is the correct answer.

Note: The solvent $DMSO$ is dimethyl sulfoxide which is having the chemical formula \[{{\left( C{{H}_{3}} \right)}_{2}}SO\] is an important polar aprotic solvent that dissolves both polar and non polar compounds and is miscible in a wide range of organic solvents as well as water, where is the chemical formula of the acetonitrile is \[C{{H}_{3}}-CN\] used as polar aprotic solvent in the organic synthesis and in the purification of the butadiene.