Question

Identify the binary mixture(s) that can be separated into individual compounds, by differential extraction, as shown in the given scheme.

• A. $C_6H_5OH$ and $C_6H_5COOH$
• B. $C_6H_5COOH$ and $C_6H_5CH_2OH$
• C. $C_6H_5CH_2OH$ and $C_6H_5OH$
• D. $C_6H_5CH_2OH$ and $C_6H_5CH_2COOH$

Answer 1

Answer: (B), (D)

(A) Both are soluble in $NaOH$, hence inseparable.
(B) Only benzoic acid $\left( C _{6} H _{5} COOH \right)$ is soluble in $NaOH$ and $NaHCO _{3}$, while benzyl alcohol $\left( C _{6} H _{5} CH _{2} OH \right)$ is not. Hence, separable.
(C) Although $NaOH$ can enable separation between benzyl alcohol $\left( C _{6} H _{5} CH _{2} OH \right)$ and phenol $\left( C _{6} H _{5} OH \right)$ as only the later is soluble in $NaOH$. However, in $NaHCO _{3}$, both are insoluble. Hence, inseparable.
(D) $\alpha$-phenyl acetic acid $\left( C _{6} H _{5} CH _{2} COOH \right)$ is soluble in $NaOH$ and $NaHCO _{3}$. While benzyl alcohol $\left( C _{6} H _{5} CH _{2} OH \right)$ is not. Hence, separable.