Organic Chemistry PYQ — Page 3

Sucrose hydrolyses in acidic medium into glucose and fructose by first order rate law with $t_{1/2} = 3$ hour. The percentage of sucrose remaining after $6$ hours is _______. (Nearest integer) (Given: $\log 2 = 0.3010$ and $\log 3 = 0.4771$)

A hydroxy compound $(\mathrm{X})$ with molar mass $122 \mathrm{~g} \mathrm{~mol}^{-1}$ is acetylated with acetic anhydride, using a large excess of the reagent ensuring complete acetylation of all hydroxyl groups. The product obtained has a molar mass of $290 \mathrm{~g} \mathrm{~mol}^{-1}$. The number of hydroxyl groups present in compound (X) is:

Consider the following reaction sequence  Compound $(\mathrm{y})$ develops characteristic colour with neutral $\mathrm{FeCl}_{3}$ solution. Identify the INCORRECT statement from the following for the above sequence.

In Carius method, 0.75 g of an organic compound gave 1.2 g of barium sulphate, find percentage of sulphur (molar mass $32 \mathrm{~g} \mathrm{~mol}^{-1}$). Molar mass of barium sulphate is $233 \mathrm{~g} \mathrm{~mol}^{-1}$.

Consider the following sequence of reactions  The major product P is:

Increasing order of electron withdrawing power of following functional groups is: a. $-CN$ b. $-COOH$ c. $-NO_2$ d. $-I$

In the given pentapeptide, find out an essential amino acid $(\mathrm{Y})$ and the sequence present in the pentapeptide:  Choose the correct answer from the options given below:

Find out the statements which are not true. A. Resonating structures with more number of covalent bonds and lesser charge separation are more stable. B. In electromeric effect, an unsaturated system shows +E effect with nucleophile and -E effect with electrophile. C. Inductive effect is responsible for high melting point, boiling point and dipole moment of polar compounds. D. The greater the number of alkyl groups attached to the doubly bonded carbon atoms, higher is the heat of hydrogenation. E. Stability of carbanion increases with the increase in $\mathrm{s}-$ character of the carbon carrying the negative charge. Choose the correct answer from the options given below:

The incorrect statement from the following with respect to carbohydrates is:

The reactions which produce alcohol as the product are: A. $\mathrm{CH}_{4}+\mathrm{O}_{2} \xrightarrow[\Delta]{\mathrm{Mo}_{2} \mathrm{O}_{3}}$ B. $2 \mathrm{CH}_{3} \mathrm{CH}_{3}+3 \mathrm{O}_{2} \xrightarrow[\Delta]{\left(\mathrm{CH}_{3} \mathrm{COO}\right)_{2} \mathrm{Mn}}$ C. $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CH} \xrightarrow{\mathrm{KMnO}_{4}}$ D. $2 \mathrm{CH}_{4}+\mathrm{O}_{2} \xrightarrow{\mathrm{Cu} / 523 \mathrm{~K} / 100 \mathrm{~atm}.}$ E. $\mathrm{CH}_{3}-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}_{3} \xrightarrow{\mathrm{KMnO}_{4} / \mathrm{H}^{+}}$ Choose the correct answer from the options given below :

Consider the following organic reaction sequence. Choose the final product $(X)$ from the following (consider the major product in all intermediate reactions) 

A mixed ether $(\mathrm{P})$, when heated with excess of hot concentrated hydrogen iodide produces two different alkyl iodides which when treated with aq. NaOH give compounds $(\mathrm{Q})$ and $(\mathrm{R})$. Both $(\mathrm{Q})$ and $(\mathrm{R})$ give yellow precipitate with NaOI. Identify the mixed ether $(\mathrm{P})$ :

The major product of which of the following reaction is not obtained by rearrangement reaction?

Consider the following compounds  Arrange these compounds in the increasing order of reactivity with nitrating mixture.

Product $C$ of the following reaction sequence will be 

"P" is a hydrocarbon of molecular formula: C$_8$H$_{14}$. On ozonolysis, "P" forms "Q". "Q" on treatment with alkali under reflux condition produces "R", which on treatment with I$_2$/NaOH gives a yellow precipitate. Acidification of the solution gives "S". The structure of "S" is given below:  The correct structure of "P" is

An alkene $(X)$ on ozonolysis followed by reduction gives following products: $H-CHO$ ($2$ moles), $H-CO-CO-CHO$, $CH_3-CO-CO-CH_3$. The alkene $(X)$ is:

One mole of an alkane (x) requires $8$ mole oxygen for complete combustion. Sum of number of carbon and hydrogen atoms in the alkane (x) is _______.

Given below are two statements: Statement I: Vapours of the liquid with higher boiling point condense before vapours of the liquid with lower boiling points in fractional distillation. Statement II: The vapours rising up in the fractionating column become richer in high boiling component of the mixture. In the light of the above statements, choose the correct answer from the options given below:

Match List-I with List-II. <table class="pyq-table"><tbody><tr><th>List-I (Purification technique)</th><th>List-II (Used to separate)</th></tr><tr><td>A. Simple distillation</td><td>I. Steam volatile compound</td></tr><tr><td>B. Fractional distillation</td><td>II. Two liquids with large difference in boiling points</td></tr><tr><td>C. Steam distillation</td><td>III. Liquid decomposing at its boiling point</td></tr><tr><td>D. Distillation under reduced pressure</td><td>IV. Two liquids with close boiling points</td></tr></tbody></table> Choose the correct answer from the options given below :

Consider the following sequence of reactions to give the major product $(X)$  $P$ g of the major product $(X)$ formed is reacted with $NaHCO_3$ solution to liberate a gas which occupied $11.2$ dm$^3$ at STP. $P = $ _____ g. (Given molar mass in g mol$^{-1}$ H:$1$, C:$12$, O:$16$, Cl:$35.5$)

A student has planned to prepare acetanilide from aniline using acetic anhydride. The student has started from 9.3 g of aniline. However, the student has managed to obtain 11 g of dry acetanilide. The % yield of this reaction is :-

Given below are two statements: Statement I: $2,6$-diethylcyclohexanone and $6$-methyl-$2$-n-propylcyclohexanone are metamers. Statement II: $2,2,6,6$-tetramethylcyclohexanone exhibits keto-enol tautomerism. In the light of the above statements, choose the correct answer from the options given below

0.53 g of an organic compound (x) when heated with excess of nitric acid (concentrated) and then with silver nitrate gave 0.75 g of silver bromide precipitate. 1.0 g of $(\mathrm{x})$ gave 1.32 g of $\mathrm{CO}_{2}$ gas on combustion. The percentage of hydrogen in the compound $(\mathrm{x})$ is $\_\_\_\_$%. [Nearest Integer] [Given: Molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{H}: 1, \mathrm{C}: 12, \mathrm{Br}: 80, \mathrm{Ag}: 108, \mathrm{O}: 16$; Compound (x) : $\mathrm{C}_{\mathrm{x}} \mathrm{H}_{\mathrm{y}} \mathrm{Br}_{\mathrm{z}}$]