Question

The alcohol obtained by the hydrolysis of oils and fats is:
(A) Glycol
(B) Glycerol
(C) Propanol
(D) Pentanol

Answer 1

Hint: Hydrolysis is a process of addition of ${{H}_{2}}O$ in order to break down the oils and fats which are a form of lipids and converts them into alcohol and respective fatty acids which are long chain carboxylic acids.The hydrolysis of fats mainly applies for the term to the operation in which ethanolic $C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}C{{H}_{2}}C{{H}_{2}}OH$ $KOH$ reacts with oil and break bonds in between them to form a trihydroxy alcohol.

Complete Step by Step Solution:
When oils and fats which are esters of long chain hydrocarbons are hydrolyzed in the presence of ${{H}_{2}}O$ and ethanolic potassium hydroxide and sometimes some enzymes like Lipase catalyses the process . The alcohol formed in the process is a trihydroxy alcohol meaning it has 3 $-OH-$ groups attached to it . And fatty acids are formed in addition with those which when removed can be used in identification of the oils or fats.

Checking options as to which alcohol from the options contains 3 hydroxyl groups that would be the answer.
A-Glycol : Here is the structure of this alcohol.It has the chemical formula as $HO-C{{H}_{2}}-CH(OH)-C{{H}_{3}}$ . As it has only 2 hydroxyl groups in this compound so it will not be the correct answer.
B-Glycerol: Here is the structure of this compound. It has the chemical formula as $HO-C{{H}_{2}}-C{{H}_{2}}(OH)-C{{H}_{2}}OH$ . As it has 3 hydroxyl groups in this compound and so it will be our correct answer .
C. Propanol: Here is the structure of this compound. It has the chemical formula as $C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}OH$. As it has only 1 hydroxyl group attached to this compound and so it will not be the correct answer.
D.Pentanol : Here is the structure of this compound. It has the chemical formula as $C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}C{{H}_{2}}C{{H}_{2}}OH$. As it has only 1 hydroxyl group attached to this compound and so it will also not be the correct answer.
Hence the correct answer will be option B.

Note: The glycol should not be misread and interpreted as glycerol as both have different structures. In glycol only 2 hydroxyl groups are attached while in glycerol 3 hydroxyl groups are attached . In hydrolysis of fats glycerol is produced not glycol.