Assertion (A) & Reason (B) MCQ

MCQ 11 Mark

Assertion $(A): 4-$nitrophenol is more acidic than $2, 4, 6-$trinitrophenol.
Reason $(R): $ Phenol is a weaker acid than carbonic acid.

A
Both $A$ and $R$ are true and $R$ is the correct explanation of $A.$
B
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A.$
C
$A$ is true but $R$ is false.
✓
$A$ is false but $R$ is true.

Answer

Correct option: D.

$A$ is false but $R$ is true.

Electron withdrawing groups such as $-\ce{NO_2, CN, - X},$ increase the acidity. Greater the number of electron$-$with drawing groups more is the acidic character, i.e. $2, 4, 6-$trinitrophenol is more acidic than $4-$nitrophenol.

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MCQ 21 Mark

Assertion (A): The nucleophilic substitution of vinyl chloride is difficult than ethyl chloride.
Reason (R): Vinyl group is an electron-donating group.

A
Both A and R are true and R is the correct explanation of A.
B
Both A and R are true but R is not the correct explanation of A.
✓
A is true but R is false.
D
A is false but R is true.

Answer

Correct option: C.

A is true but R is false.

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MCQ 31 Mark

Assertion $(A):$ Isobutanal does not give the iodoform test.
Reason $(R):$ It does not have alpha$-$hydrogen.

✓
Both $A$ and $R$ are true and $R$ is the correct explanation of $A.$
B
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A.$
C
$A $ is true but $R$ is false.
D
$A$ is false but $R$ is true.

Answer

Correct option: A.

Both $A$ and $R$ are true and $R$ is the correct explanation of $A.$

Isobutanal does not give an iodoform test because it does not have the $-\ce{COCH_3}$ group.

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MCQ 41 Mark

Assertion (A): Fructose can reduce Tollen's reagent.
Reason (R): Fructose is a ketone.

A
Both A and R are true and R is the correct explanation of A.
✓
Both A and R are true but R is not the correct explanation of A.
C
A is true but R is false.
D
A is false but R is true.

Answer

Correct option: B.

Both A and R are true but R is not the correct explanation of A.

(b) Both A and R are true but R is not the correct explanation of A.
Explanation: Fructose does not contain an aldehyde group but still reduce Tollen's reagent. In presence of the dilute solution of alkali, fructose undergoes epimerization to form glucose and mannose.

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Chemistry Assertion (A) & Reason (B) MCQ

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