Question

Fat consists of :
A. Monohydroxy carboxylic acid
B. Monohydroxy aliphatic carboxylic acid
C. Monohydroxy, aliphatic, saturated carboxylic acid
D. Dihydroxy aliphatic carboxylic acid

Answer 1

Hint: Fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The fats consist of long chains of esters which are made up of alcohols of many no. of $-{{C}_{n}}-$ bonds which contain single hydroxyl functional group and carboxylic acids .

Complete Step by Step Solution:
Fats are the class of compounds which consists of esters which are made up of reactions $bet{{w}^{n}}$ alcohols ($-OH-$) and carboxylic acids ($-COOH-$). The esters so formed have alcohols and carboxylic acids which has one hydroxyl group $-OH-$ in addition with the carboxyl group $-COOH-$$-COOH-$ and so called as monohydroxy carboxylic acids.

Aliphatic compounds are those compounds which have single long chain hydrocarbons and do not have any aromatic ring. We know that those compounds which does not have any double bond in the compounds comes under saturated compounds and that’s why the aliphatic carboxylic acids are mostly saturated which does not contains any double bond but which contains the double bond (\[=\]) comes under the unsaturated class of compounds.

An Acid is unsaturated if it has one or more double bonds between carbon atoms and so many are saturated with hydrogen. Many acids are saturated also like stearic acid which is a saturated acid and so glyceryl tristearate is a saturated fat.

Therefore, one chain of fatty acid is bonded to each one of the three -OH- groups of the glycerol by the reaction of the carboxyl end of the fatty acids with the alcohol i.e 3 chains per molecule.

Thus fats consist of monohydroxy,aliphatic,saturated carboxylic acid and so the correct option is C.

Note: All fats are carboxylic acids of long chains but not all are aliphatic and saturated carboxylic acids so this should not be confused with the fact that most are aliphatic only which does not contain any double bonds in the compound.This should be taken in consideration while reading options that all the three mentioned property must present in the fats.