a$)$ Distinguish between partition coefficient and distribution ratio

b$)$ Give any four reasons why solid phase extraction $($SPE$)$ is a better and more preferable technique to liquid$-$liquid extraction

c$)$ Benzene is one of the Toxic Air Pollutants $($TAPs$)$ found in car exhaust fumes. When a $50\mathrm{.}00mL$ aqueous sample containing a $0\mathrm{.}05000M$ benzene $($molecular weight $=78\mathrm{.}11\frac{g}{m}ol)$ is extracted twice with $10\mathrm{.}00mL$ portions of chloroform, it is found that $1\mathrm{.}50{10}^3$ moles of the original compound has been extracted into the chloroform.

i$.$ Calculate the value of the partition coefficient for the extraction of benzene in water using chloroform

ii$.$ How much is the extraction efficiency of a single extraction?

iii. Determine the total volume of the chloroform which will be needed to extract $99\%$ of the benzene from the aqueous phase.

d$)$ Glycolic acid is used in the textile industry as a dyeing and tanning agent. Given that its acid dissociation constant $(K_n)$ is $1\mathrm{.}47{10}^{-1}$ and its partition coefficient $(K_D)$ between water and benzene is $3\mathrm{.}22,$ calculate the extraction efficiency of a single extraction when $50\mathrm{.}00mL$ of

a $0\mathrm{.}025M$ aqueous solution of glycolic acid buffered to a $pH$ of $3\mathrm{.}00,$ is extracted once with

$50\mathrm{.}00mL$ of benzene.