Question

The compounds below are dissolved in diethyl ether. The solution is transferred to a separatory funnel and shaken with 10 % NaOH. (a) Which of the organic compounds (or their ions) will be in the aqueous layer? Draw the structure of each (for ions, clearly indicate the location of the charge). (b) Which of the organic compounds (or their ions) will be in the organic layer? Draw the structure of each (for ions, clearly indicate the location of the charge). (c) Which layer, prganic)or aqueous will be on top? NH2 -NO2 OH nitrobenzene benzoic acid benzophenone aniline

Answer 1

first of all, aniline, benzophenone, benzoic acid and nitro benzene have functional groups aromatic amine, ketone , carboxylic acid and nitro, respectively.

The separation of organic mixture is based on following points:

1. All aromatic organic compounds are dissolved in ether and all aliphatic (urea, oxalic acid, thio-urea) polar compounds are dissolved in water (like dissolves like), generally.

2. If compound contain carboxylic acid and insoluble in water it will be soluble in sodium bicarbonate solution as a making salt and can be regenerated with adding Conc. HCl solution (chemical separation).

If compound contain phenolic group and insoluble in water it will be soluble in sodium hydroxide solution as a making salt and can be regenerated with adding conc. HCl solution (chemical separation).

3.

If compound contain amine and insoluble in water it will be soluble in Conc. HCl solution as a making salt and can be regenerated with adding Conc. NaOH solution (chemical separation).

4. Carbohydrates are insoluble in ether therefore can be separated with adding of ether.

In this question,

1. first of all, aniline, benzophenone, benzoic acid and nitro benzene are dissolved in ether.

2. This solution is transferred in separating funnel and shaken with 10 % NaOH, here carboxylic acid means benzoic acid is soluble only and form salt (sodium benzoate).

3. In aqueous layer, benzoate ion present in aqueous layer (C₆H₅COO^-) in form of sodium benzoate (C₆H₅COO^-Na⁺).

4. Other compounds Aniline, benzophenone and nitro benzene present in organic etheral layer as such as a neutral without charged.

C₆H₅NH₂, C₆H₅COC₆H₅ and C₆H₅NO₂

5.Heavy layer will be aqueous lyer therefore it is on bottom and etheral or organic layer will be on the top(light layer).

Reaction:

C₆H₅COOH + NaOH  $\rightarrow$ (C₆H₅COO^-Na⁺) + H2O

Organic layer soluble in water (aqueous layer)