Assertion & Reason

MCQ 11 Mark

Assertion (A): ${ }_6 C ^{13}$ and ${ }_7 N ^{14}$ are called isotones.
Reason (R): Atoms of different elements having the same number of neutrons, but a different atomic number and different mass number are called isotones.

✓
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
C
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: A.

Both (A) and (R) are correct

(i) (A) and (R) are correct. (R) explain (A)

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MCQ 21 Mark

Assertion (A): $NH _3, H _2 O , HCl$ are heteroatomic molecules.
Reason $( R )$ : The molecule that consists of atoms of different elements is called heteroatomic molecules.

✓
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
C
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: A.

Both (A) and (R) are correct

(i) (A) and (R) are correct. (R) explain (A)

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MCQ 31 Mark

\Assertion (A): ${ }_{17} Cl ^{35}$ and ${ }_{17} Cl ^{37}$ are isotones.
Reason (R): Atoms of the same element have the same atomic number but a different mass number.

A
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
C
(A) is correct but (R) is wrong
✓
(A) is wrong but (R) is correct.

Answer

Correct option: D.

(A) is wrong but (R) is correct.

(iii) (A) is wrong (R) is correct

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MCQ 41 Mark

Assertion $( A ):{ }_{18} Ar ^{40}$ and ${ }_{20} Ca ^{40}$ are isobars.
Reason (R): They have the same atomic mass but a different atomic number.

✓
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
C
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: A.

Both (A) and (R) are correct

(i) A) and (R) are correct; (R) explain (A)

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MCQ 51 Mark

Assertion (A): An atom is no longer indivisible.
Reason (R): The subatomic particles protons, electrons and neutrons were discovered.

✓
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
C
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: A.

Both (A) and (R) are correct

(i) (A) and (R) are correct. (R) explain (A)

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MCQ 61 Mark

Assertion (A): ${ }_1 H ^1, \quad{ }_1 H ^2{ }_1 H ^3$ are the isotopes of hydrogen.
Reason (R): The atoms of the same element with the same mass number but different at numbers are called isotopes.
(a) Both (A) and (R) are correct
(b) Both (A) and (R) are wrong
(c) (A) is correct but (R) is wrong
(d) (A) is wrong but (R) is correct.

A
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
✓
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: C.

(A) is correct but (R) is wrong

Assertion (A) & Reason (R):
(i) (A) and (R) are correct. (R) explain (A)
(ii) (A) is correct (R) is wrong
(iii) (A) is wrong (R) is correct
(iv) (A) and (R) are correct. (R) does not explain (A).

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MCQ 71 Mark

Assertion (A): The atomicity of ozone is three.
Reason (R): 1 molecule of ozone contains 3 atoms of oxygen.
(a) Both (A) and (R) are correct
(b) Both (A) and(R) are wrong
(c) (A) is correct but (R) is wrong
(d) (A) is wrong but (R) is correct.

✓
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
C
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: A.

Both (A) and (R) are correct

(a) Both (A) and (R) are correct

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MCQ 81 Mark

Assertion (A): Atoms of the same element may not be similar in all respects.
Reason (R): Atoms of the same element have the same atomic number but a different number of neutrons.
(a) Both (A) and (R) are correct
(b) (A) is correct but (R) is wrong
(c) Both (A) and (R) are wrong
(d) (A) is wrong but (R) is correct.

A
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
✓
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: C.

(A) is correct but (R) is wrong

(b) (A) is correct but (R)is wrong

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MCQ 91 Mark

Assertion (A): Water, Ammonia $\left( H _2 O , NH _3\right)$ are heteroatomic molecules.
Reason (R): Most of the elementary gases and compounds consist of atoms of the same element.
(a) Both (A) and (R) are correct
(b) Both (A) and (R) are wrong
(c) (A) is correct but (R) is wrong
(d) (A) is wrong but (R) is correct.

✓
(A) is correct and (R) explains (A)
B
(A) is correct but (R) is wrong
C
(A) is wrong but (R) is correct
D
Both (A) and (R) are wrong

Answer

Correct option: A.

(A) is correct and (R) explains (A)

(a) (A) is correct and (R) explains (A)

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MCQ 101 Mark

Assertion (A): Water, Ammonia $\left( H _2 O , NH _3\right)$ are heteroatomic molecules.ules.
Reason (R): Most of the elementary gases and compounds consist of atoms of the same element.
(a) Both (A) and (R) are correct
(b) Both (A) and (R) are wrong
(c) (A) is correct but (R) is wrong
(d) (A) is wrong but (R) is correct.

A
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
✓
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: C.

(A) is correct but (R) is wrong

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MCQ 111 Mark

Assertion (A): Hydrogen, Oxygen and Ozone are called homoatomic molecules.
Reason (R): Homoatomic molecules are made up of atoms of the same element.
(a) Both (A) and (R) are wrong
(b) (A) is correct but (R) is wrong
(c) (A) is wrong but (R) is correct
(d) Both (A) and (R) are correct.

A
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
C
(A) is correct but (R) is wrong
✓
(A) is wrong but (R) is correct.

Answer

Correct option: D.

(A) is wrong but (R) is correct.

(d) Both (A) and (R) are correct.

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MCQ 121 Mark

Assertion (A): Atoms and molecules are the building blocks of matter.
Reason (R): Atom is the ultimate particle of an element which may or may not have an independent existence.
(a) Both (A) and (R) are wrong]
(b) (A) is correct but (R) does not explain (A)
(c) Both (A) and (R) are correct
(d) (A) is wrong but (R) is correct.

A
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
✓
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: C.

(A) is correct but (R) is wrong

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MCQ 131 Mark

Assertion (A): Nitrogen, oxygen and hydrogen are diatomic molecules.
Reason (R): $N _2, O _2, H _2 $ contain two atoms in one molecule and so they are a diatomic molecule.
(a) Both (A) and (R) are correct
(b) Both (A) and (R) are wrong
(c) (A) is correct but (R) is wrong
(d) (A) is wrong but (R) is correct.

✓
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
C
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: A.

Both (A) and (R) are correct

(a) Both (A) and (R) are correct

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MCQ 141 Mark

Assertion $( A ):{ }_6 C ^{13}$ and ${ }_7 N ^4$ are called Isotones.
Reason $( R )$ : Isotones are the atoms of the different elements with different atomic number but the same mass number.
(a) Both (A) and (R) are correct
(b)Both (A) and (R) are wrong
(c) $(A)$ is correct but $(R)$ is wrong
(d) (A) is wrong but (R) is correct.

A
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
✓
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: C.

(A) is correct but (R) is wrong

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MCQ 151 Mark

Assertion (A): $C _{12} H _{22} O _{11}$ is not a simple ratio.
Reason (R): The ratio of atoms in a molecule may be fixed and integral but may not be simple.
(a) Both (A) and (R) are correct
(b) Both (A) and (R) are wrong
(c) (A) is correct but (R) is wrong
(d) (A) is wrong but (R) is correct.

✓
Both (A) and (R) are correct
B
Both (A) and (R) are wrong
C
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct.

Answer

Correct option: A.

Both (A) and (R) are correct

(a) Both (A) and (R) are correct

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