In the following structures, which one is having staggered conformation with maximum dihedral angle?
1
2
3
4
Official Solution
Correct Option: (3)
It is the staggered conformation with maximum dihedral angle.
So, the correct option is (C).
02
PYQ 2022
medium
chemistryID: jee-main
Given below are two statements. Statement I : The chlorides of Be and Al have Cl-bridged structure. Both are soluble in organic solvents and act as Lewis bases. Statement II : Hydroxides of Be and Al dissolve in excess alkali to give beryllate and aluminate ions. In the light of the above statements, choose the correct answer from the options given below.
1
Both Statement I and Statement II are true
2
Both Statement I and Statement II are false
3
Statement I is true but Statement II is false
4
Statement I is false but Statement II is true
Official Solution
Correct Option: (4)
Let us analyze both statements given in the question:
Statement I: The chlorides of Be (beryllium) and Al (aluminum) have Cl-bridged structures. Both are soluble in organic solvents and act as Lewis bases. Analysis:
The chlorides of Be and Al (BeCl2 and AlCl3) do indeed form Cl-bridged structures. BeCl2 forms polymeric chains, while AlCl3 forms a dimer.
However, these chlorides are known to act as Lewis acids, not Lewis bases. They can accept electron pairs, which is a characteristic of Lewis acids.
Both BeCl2 and AlCl3 are soluble in organic solvents, which is consistent, but the statement about acting as Lewis bases renders the statement incorrect.
Statement II: Hydroxides of Be and Al dissolve in excess alkali to give beryllate and aluminate ions. Analysis:
Beryllium hydroxide, Be(OH)2, and aluminum hydroxide, Al(OH)3, are amphoteric. This means they can react with both acids and bases.
In excess alkali, Be(OH)2 dissolves to form the beryllate ion [Be(OH)4]2-, and Al(OH)3 dissolves to form the aluminate ion [Al(OH)4]-.
This characteristic makes Statement II true as it accurately describes the behavior of these hydroxides.
Conclusion: Based on the analysis, Statement I is false because BeCl2 and AlCl3 act as Lewis acids, not bases. Statement II is true because both hydroxides dissolve in excess alkali to form the corresponding ionic species. Thus, the correct answer is: Statement I is false but Statement II is true.
03
PYQ 2023
medium
chemistryID: jee-main
Match List-I with List-II :
List I
(Reagents Used)
List II
(Compound with Functional group detected)
A
Alkaline solution of copper sulphate and sodium citrate
I
B
Neutral FeCl3 solution
II
C
Alkaline chloroform solution
III
D
Potassium iodide and sodium hypochlorite
IV
Choose the correct answer from the options given below :
1
A-II, B-IV, C-III, D-I
2
A-IV, B-I, C-II, D-III
3
A-III, B-IV, C-I, D-II
4
A-III, B-IV, C-II, D-I
Official Solution
Correct Option: (4)
A: Alkaline solution of copper sulphate and sodium citrate detects aldehydes. The aldehyde reacts to form a reddish-brown precipitate of Cu O.
B: Neutral FeCl solution is used for detecting phenolic groups. Phenols give a characteristic color (violet or blue).
C: Alkaline chloroform solution (Haloform test) detects the presence of a methyl ketone or a methyl group adjacent to a hydroxyl group.
D: Potassium iodide and sodium hypochlorite (Iodoform test) confirms alcohol groups (-CH OH). \end{itemize}
04
PYQ 2024
medium
chemistryID: jee-main
Statement I: So disproportionates into and in alkaline medium Statement II: undergoes disproportionation in acidic medium
1
Statement I is correct but Statement Il is incorrect
2
Statement I is incorrect but Statement Il is correct
3
Both Statement I and Statement II are correct
4
Both Statement I and Statement II are incorrect
Official Solution
Correct Option: (1)
The Correct Option is (A) : Statement I is correct but Statement Il is incorrect
05
PYQ 2024
medium
chemistryID: jee-main
The total number of different alkanes formed when the following mixture is subjected to electrolysis: and is (do not consider disproportionation reaction)
Official Solution
Correct Option: (1)
The Correct Answer is : 3
06
PYQ 2026
medium
chemistryID: jee-main
Match the LIST-I with LIST-II.Choose the correct answer from the options given below:
1
A-I, B-III, C-II, D-IV
2
A-I, B-III, C-IV, D-II
3
A-III, B-I, C-IV, D-II
4
A-III, B-I, C-II, D-IV
Official Solution
Correct Option: (3)
Vitamins are essential micronutrients that the body requires in small amounts for various metabolic processes. Deficiency of these vitamins leads to specific clinical conditions.
Let us examine each pair in the given lists:
1. Scurvy: Scurvy is a disease characterized by bleeding gums and delayed wound healing. It is caused by a deficiency of Vitamin C, chemically known as Ascorbic Acid. Therefore, A matches with III.
2. Convulsions: Convulsions or seizures can be caused by a deficiency of Vitamin , which is chemically known as Pyridoxine. Vitamin is involved in the synthesis of neurotransmitters. Therefore, B matches with I.
3. Cheilosis: Cheilosis involves inflammation and cracking at the corners of the mouth. It is a classic symptom of a deficiency of Vitamin , which is also known as Riboflavin. Therefore, C matches with IV.
4. Xerophthalmia: Xerophthalmia is a condition where the eyes fail to produce tears, leading to dryness and potential blindness. It is caused by a deficiency of Vitamin A. Therefore, D matches with II.
Combining these matches, we get: A-III, B-I, C-IV, D-II.
