Consider the solvolysis of the two isomeric chiral p$-$nitrobenzoates $10$ and $11.$

$10$

$11$

$($a$)$ Draw the structure of the free ion that would be formed by complete dissociation. What

would be the stereochemistry of product formed from this ion?

$($b$)$ The compounds labeled with ${?}^{18}O$ as indicated racemize during solvolysis; ${?}^{18}O$ equilibra$-$

tion is also observed. For Isomer $10,k_{eq}=k_{\text{r}\text{a}\text{c}}.$ What does this result imply about the

structure of the ion pair?

$($c$)$ For Isomer $11,k_{eq}>k_{\text{r}\text{a}\text{c}}.$ What does this result imply about the structure of the ion

pair?

$($d$)$ Propose a reason for the difference of behavior of the two isomers.