Assertion (A) & Reason (B) MCQ

MCQ 11 Mark

Note : In the following questions a statement of Assertion $(A)$ followed by a statement of Reason $(R)$ is given. Choose the correct option out of the choices given below each question.
Assertion $(A)$ : All isotopes of a given element show the same type of chemical behaviour.
Reason $(R)$ : The chemical properties of an atom are controlled by the number of electrons in the atom.

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

Answer

Correct option: A.

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

All isotopes of an element have same number of electrons and same electronic configuration; hence their chemical properties are also same.

View full question & answer→

MCQ 21 Mark

Note : In the following questions a statement of Assertion $(A)$ followed by a statement of Reason $(R)$ is given. Choose the correct option out of the choices given below each question.
Assertion $(A)$ : It is impossible to determine the exact position and exact momentum of an electron simultaneously.
Reason $(R)$ : The path of an electron in an atom is clearly defined.

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

Answer

Correct option: C.

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

The effect of Heisenberg Uncertainty Principal is significant only for motion of microscopic objects and is negligible for that of macroscopic objects.

View full question & answer→

MCQ 31 Mark

Note : In the following questions a statement of Assertion $(A)$ followed by a statement of Reason $(R)$ is given. Choose the correct option out of the choices given below each question.
Assertion $(A)$ : Black body is an ideal body that emits and absorbs radiations of all frequencies.
Reason $(R)$ : The frequency of radiation emitted by a body goes from a lower frequency to higher frequency with an increase in temperature.

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

Answer

Correct option: B.

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

The ideal body, which emits and absorbs radiations of all frequencies, is called a black body and the radiation emitted by such a body is called black body radiation. The exact frequency distribution of the emitted eadiation $($i.e. intensity versus frequency curve of the radiation$)$ from a black body depends only on its temperature. At a given temperature, intensity of radiation emitted increases with decrease of wavelength, reaches a maximum value at a given wavelength and then starts decreasing with further decrease of wavelength.

View full question & answer→

Chemistry Assertion (A) & Reason (B) MCQ

Take a timed test