1

JEE Advanced 2019 Paper 2 Offline

MCQ (Single Correct Answer)
List-I includes starting materials and reagents of selected chemical reactions. List-II gives structures of compounds that may be formed as intermediate products and/or final products from the reactions of List-I.


Which of the following options has correct combination considering List-I and List-II?
A
(II), (P), (S), (U)
B
(I), (Q), (T), (U)
C
(II), (P), (S), (T)
D
(I), (S), (Q), (R)

Explanation


Hence, correct match of II is (P, S, U).

Hence, correct matching from List-I and List-II on the basis of given options is (II), (P), (S), (U).
2

JEE Advanced 2019 Paper 2 Offline

MCQ (Single Correct Answer)
List-I includes starting materials and reagents of selected chemical reactions. List-II gives structures of compounds that may be formed as intermediate products and/or final products from the reactions of List-I.


Which of the following options has correct combination considering List-I and List-II?
A
(III), (S) (R)
B
(IV), (Q), (R)
C
(III), (T), (U)
D
(IV), (Q), (U)

Explanation


Hence, correct match of II is (P, S, U).


Hence, correct match of (III) are T, Q, R


Hence, correct match of IV is Q, R.

Hence, correct matching from List-I and List-II on the basis of given option is (IV), (Q), (R).
3

JEE Advanced 2019 Paper 1 Offline

MCQ (Single Correct Answer)
The correct order of acid strength of the following carboxylic acids is
A
III > II > I > IV
B
I > II > III > IV
C
II > I > IV > III
D
I > III > II > IV

Explanation

Acidic nature depends upon nature of electron withdrawing group and electronegativity. Electronegativity further depends on % of s character. Higher the s-character, greater will be the electronegativity and hence tendency to loose H increases thus acidic character also increases.



sp- hybridisation (50% s character) (pKa = 1.86)



sp2 - hybridisation (33-33% s character) (pKa = 4.3)



sp2 - hybridisation (Resonance effect) (pKa = 4.5)



sp3 - hybridisation (25% s-character) (pKa = 4.8)

Hence, acidic order I > II > III > IV.

II is more acidic than III since electron donating group ($$ - OC{H_3}$$) is attached to benzene ring in III which decreases the acidic character.

On the other hand, pKa value also determined acidic nature, lower pKa value gives maximum acidic character.

Hence, option (b) is correct.
4

JEE Advanced 2018 Paper 2 Offline

MCQ (Single Correct Answer)
The desired product $$X$$ can be prepared by reacting the major product of the reactions in LIST-I with one or more appropriate reagents in LIST-II (given, order of migratory aptitude: aryl > alkyl > hydrogen)



The correct option is
A
$$P - 1;Q - 2,3;R - 1,4;S - 2,4$$
B
$$P - 1,5;Q - 3,4;R - 4,5;S - 3$$
C
$$P - 1,5;Q - 3,4;R - 5;S - 2,4$$
D
$$P - 1,5;Q - 2,3;R - 1,5;S - 2,3$$

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