An organic compound 'A' with emperical formula gives sooty flame on burning Its reaction with bromine solution in low polarity solvent results in high yield of is
1
2
3
4
Official Solution
Correct Option: (3)
Aromatic compounds burns with sooty flame
02
PYQ 2023
medium
chemistryID: jee-main
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R. Assertion A: In an Ellingham diagram, the oxidation of carbon to carbon monoxide shows a negative slope with respect to temperature. Reason R: CO tends to get decomposed at higher temperature. In the light of the above statements, choose the correct answer from the options given below
1
Both A and R are correct and R is the correct explanation of A
2
Both A and R are correct but R is NOT the correct explanation of A
3
A is correct but R is not correct
4
A is not correct but R is correct
Official Solution
Correct Option: (1)
The correct option is(A): Both A and R are correct and R is the correct explanation of A
03
PYQ 2023
medium
chemistryID: jee-main
In an oligopeptide named Alanylglycylphenyl alanyl isoleucine, the number of sp2 hybridised carbons is_____.
Official Solution
Correct Option: (1)
The correct Answer is: 10
04
PYQ 2024
medium
chemistryID: jee-main
The correct stability order of carbocations is
1
2
3
4
Official Solution
Correct Option: (2)
Correct Order: The correct stability order of the carbocations is:
(CH3)3C+ > (CH3)2CH+ > CH3–CH2+ > CH3+.
Thus, the correct order of stability for the given carbocations is:
(CH3)3C+ > (CH3)2CH+ > CH3–CH2+ > CH3+.
05
PYQ 2026
medium
chemistryID: jee-main
The statements that are incorrect about the nickel(II) complex of dimethylglyoxime are :
A. It is red in colour.
B. It has a high solubility in water at pH = 9.
C. The Ni ion has two unpaired d-electrons.
D. The N – Ni – N bond angle is almost close to 90°.
E. The complex contains four five-membered metallacycles (metal containing rings).
Choose the correct answer from the options given below :
1
C and E Only
2
B, C and E Only
3
A, D and B Only
4
C and D Only
Official Solution
Correct Option: (2)
Step 1: Understanding the Concept:
is a square planar, neutral complex. Its stability and distinct color are due to its unique structure involving intramolecular hydrogen bonding. Step 2: Detailed Explanation:
- Statement A: Correct. The complex is a rosy-red precipitate.
- Statement B: Incorrect. It is highly insoluble in water, which is why it's used for the gravimetric estimation of Nickel.
- Statement C: Incorrect. As a square planar complex with strong field behavior (from donors), it is diamagnetic (0 unpaired electrons).
- Statement D: Correct. Square planar geometry implies angles close to 90°.
- Statement E: Incorrect. It contains two five-membered chelate rings (Ni-N-C-C-N) and two six-membered rings formed by hydrogen bonding (O-H...O). Step 3: Final Answer:
The incorrect statements are B, C, and E.
06
PYQ 2026
hard
chemistryID: jee-main
Match the LIST-I with LIST-II Choose the correct answer from the options given below:
1
A–IV, B–III, C–II, D–I
2
A–II, B–I, C–IV, D–III
3
A–III, B–IV, C–I, D–II
4
A–III, B–I, C–IV, D–II
Official Solution
Correct Option: (4)
Step 1: Identify each reagent and reaction. - NH –NH , KOH is used in Wolff–Kishner reduction.
- Ag(NH ) OH is Tollen's reagent.
- Aq. CuSO , sodium potassium tartrate, KOH is used in Fehling's test.
- Zn–Hg, HCl is used in Clemmensen reduction. Step 2: Match correctly. Final Answer:
07
PYQ 2026
medium
chemistryID: jee-main
Which of the following is the correct order with respect to the property indicated?
1
Cl>F (Ionisation energy)
2
K₂O>Na₂O>Al₂O₃ (Basic nature)
3
K>Na>Mg>Al (Metallic character)
4
None of these
Official Solution
Correct Option: (2)
Step 1: Understanding the properties. - Ionisation energy: F has the highest ionisation energy because of its small size, followed by Cl. - Basic nature: As we move down the group, the basic nature increases due to the increasing ionic size and decreasing bond strength. Thus, K₂O>Na₂O>Al₂O₃ is the correct order for basic nature. - Metallic character: The metallic character decreases from left to right across the period and increases from top to bottom. Therefore, K>Na>Mg>Al is the correct order for metallic character. Step 2: Conclusion. The correct answer is (2) K₂O>Na₂O>Al₂O₃ (Basic nature) as per the analysis above.
08
PYQ 2026
medium
chemistryID: jee-main
C₆H₁₂O₃ gives positive iodoform test on hydrolysis with dil. Acid. The hydrolysis product formed gives Tollens’ and iodoform test both. Find structure of C₆H₁₂O₃.
1
1
2
2
3
3
4
4
Official Solution
Correct Option: (1)
Step 1: Understanding the reaction. On hydrolysis, C₆H₁₂O₃ gives a product that undergoes both the iodoform test and Tollens’ test. The iodoform test indicates the presence of a methyl ketone group (–COCH₃), and the Tollens’ test indicates an aldehyde group (–CHO). Step 2: Conclusion. The structure fits both tests, as it contains a methyl ketone group and an aldehyde group. Therefore, the correct answer is (1).
