Fats and Lipids Questions in English

(B) Oils and fats are triglycerides,which are esters of glycerol with long-chain fatty acids. Upon hydrolysis (saponification or acid-catalyzed hydrolysis),they break down into fatty acids and $Glycerol$ $(CH_2OH-CHOH-CH_2OH)$.

(A) The physiological calorific value of food components is as follows:
$1$. $Fat$: $9.45 \ kcal/g$
$2$. $Protein$: $5.65 \ kcal/g$ (Gross) or $4.0 \ kcal/g$ (Physiological)
$3$. $Carbohydrate$: $4.1 \ kcal/g$
Therefore,the correct order of calorific value is $Fat > Protein > Carbohydrate$.

(A) In our body,energy is stored in the form of $ATP$ (Adenosine Triphosphate).

(B) Soaps are the sodium or potassium salts of long-chain fatty acids,such as stearic,oleic,or palmitic acid. They are produced by the process of saponification,where fats or oils are treated with an aqueous alkali solution.

(C) Glycerol is a byproduct of the saponification of fats and oils.
It can also be synthesized industrially from propylene via the chlorination process to form allyl chloride,followed by hydrolysis.

(A) Oleic acid $(C_{17}H_{33}COOH)$ is an unsaturated fatty acid.
It contains one double bond in its hydrocarbon chain,with the structure $CH_3(CH_2)_7CH=CH(CH_2)_7COOH$.

(B) Waxes are chemically defined as esters of long-chain fatty acids and long-chain monohydric alcohols. Therefore,the functional group present in waxes is the $Ester$ group.

(B) The given reaction is the alkaline hydrolysis of a triglyceride (fat or oil),which is known as saponification.
The reaction is:
$CH_2(OCOR_1)-CH(OCOR_2)-CH_2(OCOR_3) + 3NaOH \to CH_2(OH)-CH(OH)-CH_2(OH) + 3R-COONa$
Here,the product $(A)$ is $CH_2(OH)-CH(OH)-CH_2(OH)$,which is commonly known as glycerol (or propane-$1,2,3$-triol).
Therefore,the correct option is $(B)$.

(C) The reaction shown is the alkaline hydrolysis of a triglyceride (a fat or oil),which is known as saponification.
When a triglyceride reacts with $NaOH$ and $H_2O$,it undergoes hydrolysis to produce the sodium salt of the fatty acid $(RCOONa)$ and glycerol $(CH_2(OH)CH(OH)CH_2OH)$.
Therefore,both products are formed.

(A) Soaps are defined as the sodium or potassium salts of long-chain fatty acids.
$C_{17}H_{35}COOK$ is potassium stearate,which is a soap.
$C_{17}H_{35}COOH$ and $C_{15}H_{31}COOH$ are fatty acids.
$(C_{17}H_{35}COO)_2Ca$ is a calcium salt,which is insoluble in water and forms scum instead of soap.
Thus,the correct option is $A$.

(C) triglyceride is an ester derived from glycerol and three fatty acids.
In a triglyceride,the three hydroxyl groups of glycerol are esterified with three fatty acid molecules.
These fatty acid chains are attached to the glycerol backbone via ester linkages,forming acyl groups.
Depending on the specific triglyceride,these three acyl groups can be the same (simple triglyceride) or different (mixed triglyceride).
However,the structure of a triglyceride molecule inherently contains $3$ acyl groups attached to the glycerol backbone.

(B) Phospholipids are a class of lipids that are major components of all cell membranes.
They are derivatives of glycerol where two of the hydroxyl groups are esterified with fatty acids (carboxylic acid residues) and the third hydroxyl group is esterified with a phosphoric acid group,which is often further linked to other polar head groups.
Therefore,the correct composition is two carboxylic acid residues and one phosphate group.

(B) Fats are triglycerides,which are triesters of glycerol with three fatty acid molecules.
They are formed by the reaction between the hydroxyl groups of glycerol and the carboxyl groups of fatty acids,resulting in the formation of an $ester$ linkage $(-COO-)$.

(A) Drying oils are oils that harden into a tough,solid film after a period of exposure to air. This property is due to the presence of high levels of polyunsaturated fatty acids,specifically $Linoleic \ acid$ and $Linolenic \ acid$,which undergo oxidative polymerization. Among the given options,$Linoleic \ acid$ is the correct component.

(A) The iodine value is a measure of the degree of unsaturation in a fat or oil.
It is defined as the mass of iodine in grams that is consumed by $100 \ g$ of a chemical substance.
Since oils and fats are triglycerides containing fatty acid chains with varying degrees of unsaturation (double bonds),the iodine value is specifically used to characterize them.

(C) triglyceride is an ester derived from glycerol and three fatty acids.
These three fatty acids can be the same or different.
Therefore,a triglyceride can have up to $3$ different acyl groups attached to the glycerol backbone.

(N/A) The process of preparing soap by heating glyceryl esters of fatty acids with aqueous sodium hydroxide is called saponification.
$(i)$ Saponification of glyceryl palmitate:
$(C_{15}H_{31}COO)_{3}C_{3}H_{5} + 3NaOH \xrightarrow{\text{Heat}} C_{3}H_{5}(OH)_{3} + 3C_{15}H_{31}COONa$ (Sodium palmitate,a soap)
$(ii)$ Saponification of glyceryl oleate:
$(C_{17}H_{33}COO)_{3}C_{3}H_{5} + 3NaOH \xrightarrow{\text{Heat}} C_{3}H_{5}(OH)_{3} + 3C_{17}H_{33}COONa$ (Sodium oleate,a soap)

(A) Sodium stearate is the sodium salt of stearic acid,which is a saturated fatty acid with an $18$-carbon chain. The chemical formula for stearic acid is $C_{17}H_{35}COOH$. Replacing the hydrogen atom of the carboxyl group with a sodium ion gives the formula $C_{17}H_{35}COONa$.

(N/A) The side product of the soap industry is glycerol.
Soaps are sodium or potassium salts of long-chain fatty acids such as stearic acid,oleic acid,and palmitic acid.
Soap is formed by heating fat (glyceryl ester of fatty acid) with aqueous sodium hydroxide. This reaction is known as saponification.
The chemical reaction is:
$CH_2OCOC_{17}H_{35}-CHOCOC_{17}H_{35}-CH_2OCOC_{17}H_{35} + 3NaOH \rightarrow 3C_{17}H_{35}COONa + CH_2OH-CHOH-CH_2OH$
In this reaction,the esters of fatty acids are hydrolysed,and the soap obtained remains in colloidal form. It is precipitated from the solution by adding $NaCl$.

(B) An asymmetric carbon atom (chiral center) is a carbon atom that is bonded to four different groups.
In the structure of testosterone,we identify the chiral centers by checking each carbon atom.
By examining the steroid backbone,we find that there are $6$ asymmetric carbon atoms.
These are the carbons at positions $8, 9, 10, 13, 14,$ and $17$ of the steroid nucleus.
Therefore,the total number of asymmetric carbon atoms is $6$.

(B) The process of making soap from fats or oils is known as $Saponification$.
It involves the alkaline hydrolysis of triglycerides (fats) using a strong base like $NaOH$ or $KOH$ to produce glycerol and the salt of a fatty acid (soap).

(A) Triglycerides are triesters of glycerol (propane-$1,2,3$-triol) and fatty acids.
When one mole of a triglyceride undergoes hydrolysis,it reacts with three moles of water to produce one mole of glycerol and three moles of fatty acids.
The chemical reaction is: $\text{Triglyceride} + 3H_2O \rightarrow \text{Glycerol} + 3 \text{Fatty Acids}$.
Therefore,if $n$ moles of triglyceride are hydrolysed,$n$ moles of propane-$1,2,3$-triol (glycerol) will be formed.

(C) $1$ molecule of glycerol combines with $3$ molecules of fatty acids to form triglyceride.
Hence,the ratio of glycerol to fatty acids is $1 : 3$.

(B) Terpenes are classified as lipids or lipid-like compounds because they are hydrophobic and soluble in organic solvents. They are synthesized from isoprene units,which are $C_5H_8$ hydrocarbon units. Chloroxylenol is an antiseptic,$BHA$ is an antioxidant,and Novestrol is a synthetic estrogen.

(B) triglyceride is an ester formed from one molecule of glycerol and three molecules of fatty acids.
During the process of hydrolysis,the ester bonds are broken by the addition of water molecules.
Since a triglyceride contains $3$ ester linkages,$3$ moles of water are required to hydrolyze $1$ mole of triglyceride into $1$ mole of glycerol and $3$ moles of fatty acids.
Therefore,for the complete hydrolysis of $n$ moles of triglyceride,$3n$ moles of water molecules are required.

(D) $Linolenic$ acid is a polyunsaturated fatty acid with the chemical formula $C_{18}H_{30}O_2$.
It contains $18$ carbon atoms and $3$ carbon-carbon double bonds $( > C=C < )$.
The structure is $CH_3CH_2CH=CHCH_2CH=CHCH_2CH=CH(CH_2)_7COOH$.
Therefore,the number of $ > C=C < $ bonds present in a linolenic acid molecule is $3$.

(B) The general formula for saturated fatty acids is $C_{n}H_{2n+1}COOH$.
For $n = 17$,the formula becomes $C_{17}H_{2(17)+1}COOH = C_{17}H_{35}COOH$.
Since $C_{17}H_{35}COOH$ (stearic acid) follows this general formula,it is a saturated fatty acid.

(C) Fats are formed by the reaction of glycerol (a trihydric alcohol) with long-chain fatty acids (carboxylic acids).
This reaction is an esterification process,resulting in the formation of triacylglycerols.
Chemically,these are classified as esters of glycerol and are commonly known as glycerides.

(B) Fats and oils are triesters of glycerol with long-chain fatty acids,commonly known as triglycerides.
They are formed by the esterification of glycerol $(CH_2OH-CHOH-CH_2OH)$ with three molecules of higher carboxylic acids (fatty acids).
Therefore,fats are esters of glycerol.

(A) Saponification is the alkaline hydrolysis of a triglyceride (a triester of glycerol and fatty acids).
The general reaction is: $\text{Triglyceride} + 3NaOH \rightarrow \text{Glycerol} + 3 \times \text{Soap (Fatty acid salt)}$.
According to the stoichiometry of the reaction,$1$ mole of triglyceride produces $1$ mole of glycerol.
Therefore,$n$ moles of triglyceride will produce $n$ moles of glycerol.

(D) Soaps are defined as the sodium or potassium salts of long-chain fatty acids (higher fatty acids).
They are typically prepared by the saponification of fats or oils using $NaOH$ or $KOH$.

(C) Saponification of oils yields a triol (glycerol).
Drying (hardening) of oil involves hydrogenation.
Refining of oil is done by distillation or other such processes,not by hydrogenation.
Antioxidants are added to prevent the oxidation of oil,thus they minimize rancidity.

(D) Waxes are esters formed by the reaction of long-chain fatty acids with long-chain monohydric alcohols,such as myricyl alcohol or cetyl alcohol.

(A) Oils are liquids at room temperature because they contain a high proportion of unsaturated fatty acid residues,such as oleic acid,linoleic acid,and linolenic acid. These residues form esters known as oleates. In contrast,fats are solids at room temperature and contain a high proportion of saturated fatty acid residues like myristic,palmitic,and stearic acids. For example,glyceryl trioleate (triolein) is an oil,while glyceryl tristearate (tristearin) is a fat.

(D) $1$ mole of linseed oil has the maximum number of moles of hydrogen added because it contains the highest degree of unsaturation.
Linseed oil is a typical drying oil.
It consists primarily of linolenic acid esters (polyunsaturated fatty acids),which have multiple double bonds,allowing for the addition of more hydrogen compared to other oils listed.

(C) The iodine value is a measure of the degree of unsaturation in fats and oils. Higher unsaturation leads to a higher iodine value. $Ghee$ is primarily composed of saturated fatty acids,making it the least unsaturated among the given options. Therefore,it has the least iodine value.