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Organic Chemistry – Some Basic Principles and Techniques

JEE Main 2024 (Online) 6th April Evening ShiftNumericalMedium📈 Topic in 8% papers+4
Ques. 1JEE Main 2024, 6 April (Evening Shift)

Number of carbocations from the following that are not stabilized by hyperconjugation is . [figure]

Answer

5

Solution

Hyperconjugation needs C–H σ bonds on the carbon attached to C+ (α-H on an sp³ carbon).

1st: (CH3)2 +C-CH2CH3 has 8 α-H ⇒ stabilized

2nd: both α-carbons of the tert-butyl groups are quaternary (no α-H) ⇒ not

3rd: +CH3 has no α-carbon ⇒ not

4th: ring α-carbons are sp² (their C–H lie in the ring plane) ⇒ not

5th: +CH2-OCH3 – α-atom is O (resonance, not hyperconjugation) ⇒ not

6th: (CH3)3C+ has 9 α-H ⇒ stabilized

7th: (CH3)2N- +CH2 – α-atom is N (resonance) ⇒ not

∴ not stabilized by hyperconjugation = 5

Answer: 5

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Ques. 2JEE Main 2024, 5 April (Morning Shift)

Number of and bonds present in ethylene molecule is respectively :

  1. 3 and 1
  2. 5 and 1
  3. 4 and 1
  4. 5 and 2
Ques. 3JEE Main 2024, 5 April (Evening Shift)

The correct nomenclature for the following compound is : [figure]

  1. 2-carboxy-4-hydroxyhept-7-enal
  2. 2-formyl-4-hydroxyhept-7-enoic acid
  3. 2-carboxy-4-hydroxyhept-6-enal
  4. 2-formyl-4-hydroxyhept-6-enoic acid
Ques. 4JEE Main 2024, 4 April (Morning Shift)

What will be the decreasing order of basic strength of the following conjugate bases? -OH, R O, CH3CO O, C l

  1. C l > R O > -OH > CH3CO O
  2. -OH > R O > CH3CO O > C l
  3. C l > -OH > R O > CH3CO O
  4. R O > -OH > CH3CO O > C l
Ques. 5JEE Main 2024, 4 April (Morning Shift)

Match List I with List II : Choose the correct answer from the options given below :

  1. (A) - (I), (B) - (II), (C) - (IV), (D) - (III)
  2. (A) - (II), (B) - (IV), (C) - (III), (D) - (I)
  3. (A) - (III), (B) - (I), (C) - (II), (D) - (IV)
  4. (A) - (IV), (B) - (III), (C) - (I), (D) - (II)
Ques. 6JEE Main 2024, 4 April (Morning Shift)

Which among the following is incorrect statement?

  1. The electromeric effect is a temporary effect
  2. Hydrogen ion (H+) shows negative electromeric effect
  3. The organic compound shows electromeric effect in the presence of the reagent only.
  4. Electromeric effect dominates over inductive effect
Ques. 7JEE Main 2024, 4 April (Evening Shift)

Correct order of stability of carbanions is : [figure]

  1. d > c > b > a
  2. c > b > d > a
  3. d > a > c > b
  4. a > b > c > d
Ques. 8JEE Main 2024, 4 April (Evening Shift)

The total number of 'sigma' and 'pi' bonds in 2-oxohex-4-ynoic acid is .

Ques. 9JEE Main 2024, 4 April (Evening Shift)

Vanillin compound obtained from vanilla beans, has total sum of oxygen atoms and electrons is .

Ques. 10JEE Main 2024, 1 February (Morning Shift)

Ionic reactions with organic compounds proceed through : Choose the correct answer from the options given below :

  1. (A) only
  2. (B) only
  3. (C) only
  4. (D) and (E) only
Ques. 11JEE Main 2024, 1 February (Evening Shift)

The functional group that shows negative resonance effect is :

  1. -OH
  2. -OR
  3. -COOH
  4. -NH2

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