Question

Assertion (A): When HCl is added to Zinc granules, a chemical reaction occurs.
Reason (R): Evolution of a gas and change in colour indicates that the chemical reaction is taking place.
(1 Point)
There are two statements Assertion (A) and Reason (R) given above. Read them carefully and choose the correct option if,
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.
D. A is false but R is true.. ​

Answer 1

Answer:

assertion and reason assrrtion (A) when HCL is added to zinc granules a chemical reaction occurs. Reason (R) evolution of gas and change in colour indicate that the chemical reaction is taking place.

Answer 2

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

Assertion (A): When HCl is added to Zinc granules, a chemical reaction occurs.

Zinc reacts with hydrochloric acid when HCl is added to zinc granules as follows:

$HCl+Zn$ → $ZnCl_{2} + H_{2}$

The above reaction is a redox reaction, in which zinc is oxidised while chlorine is reduced.

Thus, the assertion statement is true.

Reason (R): Evolution of a gas and change in colour indicates that the chemical reaction is taking place.

From the above reaction, it can be seen that hydrogen gas is liberated as the chemical reaction takes place.

Besides this, zinc granules have a greyish blue colour. While zinc chloride has a white crystalline appearance.

Thus, the evolution of gas and change in colour indicates that the chemical reaction is taking place. Hence, the reason statement is correct.

However, the reason statement mentions the effect of assertion statement. It does not explain how the chemical reaction occurs. Therefore, it is not the correct explanation.