Q: 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.

Statement I: Metamerism arises due to different alkyl chains on either side of a polyvalent functional group. In ketones, the carbonyl group (>C=O) acts as the polyvalent functional group. In 2,6-diethylcyclohexanone, the alkyl groups attached to the -carbons are two ethyl groups. In 6-methyl-2-n-propylcyclohexanone, the alkyl groups are a methyl group and an n-propyl group. Since the alkyl groups around the carbonyl group are different while the molecular formula remains the same, they are meta

Question 1

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: T

Accepted Answer

In fractional distillation, the temperature of the fractionating column decreases from bottom to top. As the vapours of the mixture rise, they cool and undergo condensation. The component with the higher boiling point condenses at a higher temperature, meaning it condenses earlier (lower down the column) than the component with the lower boiling point. Thus, Statement I is true. As the vapours rise up the fractionating column, the higher boiling component continuously condenses and falls back as

Question 2

The total number of aromatic compounds/species from the following is

Accepted Answer

A species is aromatic if it is cyclic, planar, fully conjugated (continuous cyclic overlap of p-orbitals) and contains (4n + 2)\, electrons (Huckel's rule). Let us analyse each species. 1,4-Benzoquinone: The six-membered ring has only 4 electrons (from the two C=C bonds); the two C=O groups are cross-conjugated and do not contribute to a continuous (4n + 2)\, ring system. Hence, it is non-aromatic. Tropylium cation: A planar, cyclic, fully conjugated seven-membered system with three C=C bonds an

Question 3

Given below are two statements : Statement I : A mixture of C_ 12 H_ 22 O_ 11 (sugar) and NaCl can be separated by dissolving sugar in alcohol, due to differential solubility. Statement II : Rose esse

Accepted Answer

Statement I : Sugar ( C _ 12 H _ 22 O _ 11 ) is soluble in alcohol, whereas sodium chloride ( NaCl ) is insoluble in alcohol. Therefore, a mixture of sugar and salt can be separated based on their differential solubility in alcohol. This statement is true. Statement II : Steam distillation is used to separate and purify organic compounds that are steam volatile and immiscible (insoluble) in water. Rose essence (essential oil) from rose petals possesses these properties, making steam distillation

Question 4

Shown below is the structure of methyl acetate with three different , and carbon - oxygen bonds. The correct order of bond lengths of these bonds is :

Accepted Answer

In methyl acetate, the bond is a C=O double bond, which is the shortest among the three. The bond is a C-O single bond adjacent to a carbonyl group. Due to resonance (CH_3-C(=O)-O-CH_3 CH_3-C(-O^-)=O^+-CH_3), the bond acquires partial double bond character, making it shorter than a pure single bond. The bond is a pure C-O single bond between an sp^3 hybridized carbon and oxygen, with no resonance involvement. Thus, it is the longest bond. Therefore, the correct order of bond lengths is Answer: <

Question 5

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.

Accepted Answer

Statement I: Metamerism arises due to different alkyl chains on either side of a polyvalent functional group. In ketones, the carbonyl group (>C=O) acts as the polyvalent functional group. In 2,6-diethylcyclohexanone, the alkyl groups attached to the -carbons are two ethyl groups. In 6-methyl-2-n-propylcyclohexanone, the alkyl groups are a methyl group and an n-propyl group. Since the alkyl groups around the carbonyl group are different while the molecular formula remains the same, they are meta

Question 6

Match List-I with List-II. List-I (Purification technique) List-II (Used to separate) A. Simple distillation I. Steam volatile compound B. Fractional distillation II. Two liquids with large difference

Accepted Answer

Simple distillation is used to separate two liquids with a large difference in boiling points. Fractional distillation is used to separate two liquids with close boiling points. Steam distillation is used to separate steam volatile compounds. Distillation under reduced pressure is used to separate liquids that decompose at their boiling points. Therefore, the correct match is A-II, B-IV, C-I, D-III. Answer: A-II, B-IV, C-I, D-III

Question 7

Identify the correct IUPAC name of hydrocarbon (x) containing three primary carbon atoms and with molar mass 72 g mol ^ -1 .

Accepted Answer

Let the hydrocarbon be an alkane with general formula C_nH_ 2n+2 . Molar mass = 14n + 2 = 72 14n = 70 n = 5 The molecular formula is C_5H_ 12 . The structural isomers of C_5H_ 12 are: n-pentane: CH_3-CH_2-CH_2-CH_2-CH_3 (2 primary carbons) 2-methylbutane: CH_3-CH(CH_3)-CH_2-CH_3 (3 primary carbons) 2,2-dimethylpropane: C(CH_3)_4 (4 primary carbons) The hydrocarbon with exactly three primary carbon atoms is 2-methylbutane. Answer: 2-Methylbutane

Question 8

Given below are two statements: Statement I: On the basis of inductive effect, the order of stability of alkyl carbanions is CH_3^- > CH_3-CH_2^- > (CH_3)_2CH^- > (CH_3)_3C^-. Statement II: Allyl and

Accepted Answer

Statement I is correct because alkyl groups exert a +I effect (electron-donating inductive effect). This increases the electron density on the negatively charged carbon atom, destabilizing the carbanion. Thus, as the number of alkyl groups increases, the stability of the carbanion decreases. The order of stability is CH _3^- > CH _3 CH _2^- > ( CH _3)_2 CH ^- > ( CH _3)_3 C ^-. Statement II is incorrect because allyl and benzyl carbanions are highly stabilized by the resonance effect, where the

Question 9

In an estimation of sulphur by Carius method 0.2 g of the substance gave 0.6 g of BaSO_4. The percentage of sulphur in the substance is _____ %. (Given molar mass in g mol^ -1 S : 32, BaSO_4 : 233)

Accepted Answer

Mass of the organic compound, W = 0.2 g Mass of BaSO _4 formed, m = 0.6 g Molar mass of BaSO _4 = 233 g mol ^ -1 Molar mass of S = 32 g mol ^ -1 The percentage of sulphur in the organic compound is given by the formula: \% S = 32 233 m W 100 Substituting the given values: \% S = 32 233 0.6 0.2 100 \% S = 32 233 3 100 \% S = 9600 233 41.20\% Rounding off to the nearest integer, the percentage of sulphur is 41. Answer: 41

Question 10

Consider the following molecules/species: (x) tropone, (y) acetone, (z) acetate ion The correct order of carbon – oxygen double bond length is:

Accepted Answer

In acetone (y), the carbon-oxygen bond is a localized double bond with a bond order of approximately 2. In the acetate ion (z), there are two equivalent resonance structures that delocalize the negative charge equally over both oxygen atoms. This results in a carbon-oxygen bond order of exactly 1.5. In tropone (x), the carbon-oxygen double bond is conjugated with the system of the seven-membered ring. Polarization of the C=O bond leads to a resonance structure with a single C-O^ - bond and a pos

Question 11

The following structures are

Accepted Answer

The given structures have a central carbon atom bonded to four groups: - Br , - Cl , - CH _3, and - Me . Since - CH _3 and - Me both represent the same alkyl group (methyl), the central carbon atom is bonded to two identical groups. For a carbon atom to be a chiral center, it must be bonded to four different groups. Because this condition is not met, the central carbon is not a stereocenter and the molecule is achiral. Both structures represent the same achiral compound (2-bromo-2-chloropropane)

Question 12

In sulphur estimation, 2.0 10^ -3 mol of an organic compound (X) (molar mass 76 g mol^ -1 ) gave 0.4813 g of barium sulphate (molar mass 233 g mol^ -1 ). The percentage of sulphur in the compound (X)

Accepted Answer

Mass of the organic compound (X) can be calculated as: Mass of X = Moles Molar mass Mass of X = 2.0 10^ -3 mol 76 g mol ^ -1 = 0.152 g In the Carius method for sulphur estimation, the mass of sulphur in the given mass of BaSO _4 is: Mass of S = 32 233 Mass of BaSO _4 Mass of S = 32 233 0.4813 g 0.0661 g The percentage of sulphur in the organic compound is given by: \% of S = Mass of S Mass of X 100 \% of S = 0.0661 0.152 100 43.487 \% To express this in the requested format: 43.487 \% = 434.87 1

Question 13

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

Accepted Answer

The electron withdrawing power (-I effect) of various functional groups follows the standard experimental order: -NO_2 > -CN > -COOH > -F > -Cl > -Br > -I Based on this series, the increasing order of electron withdrawing power for the given groups is: -I This corresponds to the sequence d Answer: d < b < a < c

Question 14

2.0 g of a bromo hydrocarbon (X) was subjected to Carius analysis, gave 3.36 g of AgBr. The percentage of carbon in the compound (X) is 26.7\%. Total number of carbon atoms in the empirical formula fo

Accepted Answer

Mass of AgBr formed = 3.36 g Molar mass of AgBr = 108 + 80 = 188 g mol^ -1 Moles of AgBr formed = 3.36 188 0.01787 mol Since 1 mole of AgBr contains 1 mole of Br, moles of Br in the compound = 0.01787 mol. Mass of Br = 0.01787 80 = 1.43 g Percentage of Br in compound (X) = 1.43 2.0 100 = 71.5\% Given percentage of C = 26.7\% Percentage of H = 100\% - (71.5\% + 26.7\%) = 1.8\% Now, we find the molar ratio of the elements in the compound: Moles of C = 26.7 12 = 2.225 Moles of H = 1.8 1 = 1.8 Moles

Question 15

Complete combustion of X g of an organic compound gave 0.25 g of CO_2 and 0.12 g of H_2 O. If the % of carbon is 25\% and of hydrogen is 4.89\%, then X = _____ 10^ -3 g. (Nearest integer) (Molar mass

Accepted Answer

Mass of carbon in the compound is calculated from the mass of CO_2 produced: Mass of C = 12 44 mass of CO_2 = 12 44 0.25 = 3 44 g Given that the percentage of carbon in the compound is 25\%: \% of C = Mass of C Total mass X 100 25 = 3 44 X 100 X = 3 44 100 25 = 3 44 4 = 3 11 g X 0.2727 g Verifying this using the percentage of hydrogen: Mass of H = 2 18 mass of H_2O = 2 18 0.12 = 1 75 g \% of H = 1 75 X 100 = 4.89 X = 100 75 4.89 0.2727 g Thus, X = 272.7 10^ -3 g. Rounding to the nearest integer,

Question 16

Given below are two statements: Statement I: In O_2 N-C_6 H_4-CH^ -C_6 H_4-OCH_3, the carbocation is stabilised by +R effect of -OCH_3 group. Statement II: In O_2 N-C_6 H_4-CH^ -C_6 H_4-OCH_3, the car

Accepted Answer

Statement I is true because the -OCH_3 group is an electron-donating group. It donates electron density through resonance (+R effect), which delocalizes the positive charge of the carbocation and stabilizes it. Statement II is true because the -NO_2 group is a strong electron-withdrawing group. It withdraws electron density through resonance (-R effect), which delocalizes the negative charge of the carbanion and stabilizes it. Therefore, both Statement I and Statement II are true. Answer: Both S

Question 17

In IUPAC nomenclature, the correct order of decreasing priority of functional group is :

Accepted Answer

The correct order of decreasing priority for functional groups in IUPAC nomenclature is: Carboxylic acids (-COOH) > Sulphonic acids (-SO_3H) > Esters (-COOR) > Acid halides (-COX) > Amides (-CONH_2) > Nitriles (-CN) > Aldehydes (-CHO) > Ketones (>C=O) > Alcohols (-OH) > Thiols (-SH) > Amines (-NH_2) > Alkynes (-C C-). Checking the given options: Option (A) is incorrect because -CHO has a higher priority than >C=O. Option (B) is incorrect because -COOCH_3 has a higher priority than -CONH_2. Optio

Question 18

The cyclic cations having the same number of hyperconjugation are : Choose the correct answer from the options given below :

Accepted Answer

A: Cation at C_1. -carbons are Methyl (3H), C_2 (1H), C_6 (2H). Total = 6. B: Cation at C_1. -carbons are Methyl (3H), C_2 (2H), C_6 (2H). Total = 7. C: Cation at C_1. -carbons are Methyl (3H), C_2 (1H), C_6 (2H). Total = 6. D: Cation at C_1. -carbons are Ethyl group's CH_2 (2H), C_2 (1H), C_6 (2H). Total = 5. A and C both have 6 -hydrogens, thus they have the same number of hyperconjugation structures.

Question 19

CORRECT order of stability for the following is CH _ 2 = CH ^ - , CH _ 3 - CH _ 2 ^ - , CH C ^ -

Accepted Answer

Carbanion stability is determined by the s-character of the hybrid orbital bearing the negative charge. The acetylide anion CH C^- has the carbanion on an sp hybridized carbon (50% s-character), providing optimal stabilization through efficient overlap with the charged orbital. The vinyl anion CH_2 = CH^- has the carbanion on an sp² hybridized carbon (33% s-character), offering moderate stabilization. The primary alkyl anion CH_3 - CH_2^- has the carbanion on an sp³ hybridized carbon (25% s-char

Question 20

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 ( x ) gave 1.32 g of CO _ 2 gas

Accepted Answer

From AgBr precipitate: 0.75 g AgBr (M = 188) equals 0.00399 mol Br, so the compound has one Br atom. From combustion of 1.0 g: 1.32 g CO₂ (M = 44) equals 0.03 mol C. The molar mass is found from 0.53 g sample: M = (0.53 × 188)/(0.75 × 1) = 133 g/mol. From 1.0 g sample producing 0.03 mol CO₂ We have (1.0/133) × x = 0.03, giving x = 4. Thus the molecular formula is C_4H_5Br with M = 48 + 5 + 80 = 133. Percentage of hydrogen = (5/133) × 100 = 3.76%, which rounds to 4%.

General Organic Chemistry — Previous Year Questions & Solutions