(i) Glucose has aldehyde group whereas fructose has keto group.
(ii) n-hexane is formed,

(iii) Peptide linkage.

The aliphatic carboxylic acids are stronger acids than phenols. The difference in the relative acidic strengths can be understood if we compare the resonance hybrids of carboxylate ion and phenoxide ion.
(i) The electron charge in the carboxylate ion is more dispersed in comparison to the phenoxide ion since 'there are two electronegative oxygen atoms in carboxylate ion as compared to only one oxygen atom in phenoxide ion.
(ii) Carboxylate ion is stabilised by two equivalent resonance structures in which negative charge is on more electronegative O atom. But phenoxide ion has non-equivalent resonance structures in which the negative charge is also on less electronegative carbon atom. 
Therefore, the carboxylate ion is relatively more stable as compared to phenoxide ion. Thus, the release of H⁺ ion from carboxylic acid is comparatively easier or it behaves as a stronger acid than phenol.

(i) \(2CH_{ 3 }COONa\overset { Electrolysis }{ \longrightarrow } 2CH_{ 3 }COO^{ - }+2Na^{ + }\)

At anode : \(2CH_{ 3 }COO^{ - }\longrightarrow \overset { CH_{ 3 } }{ \underset { CH_{ 3 } }{ | } } +2CO_{ 2 }+2e^{ - }\)
At Cathode : \(2H^++2e^-\rightarrow H_2(g)\)
(ii) \(_{ CH_{ 3 }COO }^{ CH_{ 3 }COO }{ _{ \diagup }^{ \diagdown }{ Ca } }\quad \overset { Dry }{ \underset { distillation }{ \longrightarrow } } \underset { Acetone }{ CH_{ 3 }COCH_{ 3 } } +CaCO_{ 3 }\)
(iii) \(\underset { Sodium\quad benzoate }{ C_{ 6 }H_{ 5 }COONa } +\underset { Soda\quad lime }{ NaOH(CaO) } \overset { \triangle }{ \longrightarrow } \underset { Benzene }{ C_{ 6 }H_{ 6 } } +\underset { sodium\\ carbonate }{ Na_{ 2 }CO_{ 3 } } \) 

(a) Isoelectric point: It is the pH at which +ve and -ve charges on zwitter ion are equal, e.g., amino acid exists as zwitter ion at pH =5.5 to 6.3.
(b) Mutarotation : It is a spontaneous change in optical rotaion when an optically active substance is dissolved in water, e.g., \(\alpha\)-glucose, when dissolved  in water, its optical rotaion changes from 111^o to 52.5^o.
(c)Enzymes : They are biological catalysts which catalyse specific biochemical reactions, e.g., 
\(\underset { sucrose }{ C_{ 12 }H_{ 22 }O_{ 11 } } +H_{ 2 }O\quad \overset { invertase }{ \longrightarrow } \underset { Glucose }{ C_{ 6 }H_{ { 12 } }O_{ 6 } } +\underset { Fructose }{ C_{ 6 }H_{ 12 }O_{ 6 } } \)
Most of enzymes are globular proteins.

(i)The ion whose one end is positively charged and other end is negatively charged is called Zwitter ion, e.g., 
\({ H }_{ 2 }N-CH_{ 2 }-COOH\rightleftharpoons { H }_{ 3 }^{ \oplus }N-CH_{ 2 }-COO^{ - }\)
(ii) Glycosidic Linkage: The oxide linkage between monosachharide units in oligo and polysachharide is called glycosidic linkage, e.g.

The products obtained on hydrolysis of sucrose are D-(+)-glucose and D-(-)-fructose.

Denaturation of proteins. Whenever proteins are subjected to changes in pH, action of heat, presence of electrolytes and radiations, they undergo structural changes leading to even the opening up of the folded structure. The changed state of proteins is called denaturation state. This causes a permanent loss of activity of proteins.
Effect of denaturation on the structure of proteins. During denaturation, the protein molecule uncoils from an ordered and specific conformation into a more random conformation. Denaturation does not change the primary structure of protein but results from a rearrangement of secondary and tertiary structures.

The electron-donating resonance effect (+R-effect) of the benzene ring increases the electron density in the carbonyl group of benzaldehyde. This, in turn, increases the electron density in the C-H bond of the aldehyde group. As a result, the C-H bond becomes stronger and hence only stronger oxidising agents like Tollens' reagent, Ag(NH₃)\(+\\ 2\) \(({ E° }_{ { Ag }^{ + }/Ag }=+0.18V)\) can oxidise C-H to C-OH to form carboxylic acids but weaker oxidising agents like Fehling's solution (Cu²⁺ + tartrate ion + base) .and Benedict's (Cu²⁺ + citrate ion + base) solution \(({ E° }_{ { Cu }^{ + }/Cu }=0.18V)\) fail to oxidise benzaldehyde to benzoic acid.
Thus, in general, all these three reagents oxidise aliphatic aldehydes but only Tollens' reagent oxidises aromatic aldehydes.

Benzoic acid and phenol Benzoic acid reacts with sodium bicarbonate to produce effervescence of carbon dioxide. whereas phenol does not.

Evidences on the basis of which glucose was assigned the given structure are as follows
(i) Glucose on reaction with HI produces n-hexane which indicates presence of six carbon atoms linked in a straight chain.
\(\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6 \xrightarrow{\mathrm{HI}} n \text {-hexane }\)
(ii) Glucose on reaction with acetic anhydride produces glucose pentaacetate which indicates presence of five -OH groups.
\(\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6 \xrightarrow{\mathrm{Ac}_2 \mathrm{O}} \text { Glucose pentaacetate }\)
(iii) Glucose on oxidation with bromine water produces gluconic acid indicates presence of -CHO group.
\(\text { Glucose } \xrightarrow{\mathrm{Br}_2 / \mathrm{H}_2 \mathrm{O}} \text { Gluconic acid }\)
iv) Glucose on reaction with HNO₃ produces saccharic acid, which indicates the presence of one primary -OH group.

(i) Vitamin B-complex and vitamin C are water soluble vitamins.
(ii) Vitamin C is chemically ascorbic acid while vitamin D is ergocalciferol.
(iii) Green leafy vegetables like spinach, cabbage, carrot etc.
(iv) It is essentially needed for body. The deficiency of vitamin K leads to blood clotting and even harmorrhage

(i) Amino acids have zwitterionic structure. Therefore. in presence of strong acids the} exist as cations' (I) and thus on electrolysis, these migrate towards cathode.
\(\overset { + }{ { NH }_{ 3 } } -CHR-{ COO }^{ - }+{ H }^{ + }\longrightarrow \quad \overset { + }{ { NH }_{ 3 } } -CHR-{ COO }H\\ \quad \quad Zwitterion\quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad Cation(I)\)
In contrast, in presence of alkalies, the amino acids exist as anions (II) and thus on electrolysis, these migrate towards anode.
\(\overset { + }{ { NH }_{ 3 } } -CHR-{ COO }^{ - }+{ OH }^{ - }\longrightarrow \quad \overset { + }{ { NH }_{ 3 } } -CHR-{ COO }H\\ \quad \quad Zwitterion\quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad Anion(II)\\ \)
(ii) A monoamino monocarboxylic acid such as glycine exists as a dipolar ion \((\overset { + }{ { NH }_{ 3 } } -{ CH }_{ 2 }-{ COO }^{ - })\) .In this structure, \(\overset { + }{ { NH }_{ 3 } } \) group acts as the acid and \({ COO }^{ - }\) group acts as the base. Thus, monoamino monocarboxylic acids can act both as an acid as well as a base. Therefore, these acids have two pK values one as an acid (when titrated with a base) and other as a base (when titrated with an acid).

(a) (i) Add sodium bicarbonate to aqueous solution of benzoic acid and ethyl benzoate separately. Brisk effervescence due to CO₂ will confirm benzoic acid. Ethly benzoate will not react.
(ii) Add I₂ and NaOH. Benzaldehyde does not give yellow ppt. whereas acetophenone give yellow ppt. due to iodoform."

acetaldehyde contains \(\alpha \)- hydrogens and hence does not undergo aldol condensation