Final answer:
Upon extraction of a mixture of benzoic acid, ethyl-4-amino-benzoate, and fluorenone in diethyl ether with dilute NaOH, sodium benzoate will appear in the aqueous phase because benzoic acid reacts with NaOH to form its sodium salt. So the correct option is B.
Step-by-step explanation:
If you dissolve benzoic acid, ethyl-4-amino-benzoate, and fluorenone in diethyl ether and extract with dilute NaOH, the substance that will appear in the aqueous phase is sodium benzoate. This is because benzoic acid is an acid and can react with NaOH to form the corresponding sodium salt, which is sodium benzoate; the reaction can be represented by the equation:
Benzoic acid (C6H5COOH) + NaOH → Sodium benzoate (C6H5COONa) + H2O
Ethyl-4-aminobenzoate (also known as benzocaine) is a weak base and does not react with NaOH under these conditions, and fluorenone is neutral and will not react with NaOH either. Therefore, they will both remain in the diethyl ether layer.