Assertion (A) & Reason (B) MCQ

MCQ 11 Mark

Assertion (A): Each side of a cube is measured to be 7.203 m . What is the volume of the cube to appropriate significant figure $373.7 m^3$.
Reason (R): The mass of one mole of a substance in grams is called its average atomic mass.

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.

(c) A is true but R is false.
$
\begin{aligned}
& \text { Explanation: Side of a cube }=7.203 m=(7.203)^3 \\
& =373.714 m^3 \\
& \therefore \text { Volume of a cube }=373.7 m^3
\end{aligned}
$
The mass of one mole of a substance in grams is called its molar mass. The molar mass in grams is numerically equal to atomic/molecular/formula mass in u .

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MCQ 21 Mark

Assertion (A): Hydrogen atom has only one electron in its orbit. But it produces several spectral lines.
Reason (R): There are many excited energy levels available.

✓
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.

(a) Both A and R are true and R is the correct explanation of A .
Explanation: A $\rightarrow$ Different lines correspond to different transitions.
B $\rightarrow$ Different transitions are due to different excited states available.

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MCQ 31 Mark

Assertion (A): The presence of $Ag ^{+}$enhances the solubility of alkenes in water.
Reason (R): Alkenes are weakly polar in nature.

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: $Ag ^{+}$coordinates with the alkene by $p \pi-d \pi$ bonding giving an ion and the solubility increases.

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MCQ 41 Mark

Assertion (A): Same number of electron pairs are present in resonance structures.
Reason (R): Resonance structures differ in the location of electrons around the constituent atoms.

✓
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.

(a) Both A and R are true and R is the correct explanation of A .
Explanation: In resonance the structures differ only in location of electrons around the constituent atoms, that is why these have same number of electron pairs, and also unpaired electrons are same.

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Chemistry Assertion (A) & Reason (B) MCQ

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