Question

(a). Assertion (A) is true, Reason (R) is also true, Reason (R) is the correct explanation for assertion (A).
(b). Assertion (A) is true, Reason (R) is true, Reason (R) is not the correct explanation for Assertion (A).
(c). Assertion (A) is true, Reason (R) is false.
(d). Assertion (A) is false, Reason (R) is true.
Q. Assertion (A): to a solution of potassium chromate, if a strong acid is added, it changes its colour from yellow to orange.
Reason (R): The colour change is due to the change in oxidation state of potassium chromate.

Answer 1

Correct Answer - C
Assertion (A) is true, (R) is false. There is no change in the oxidation state of `Cr` which is `+6` in both cases.
`2overset(2+)(Cr)O_4^(2-)+SO_4^(2-)+2H^(o+)tooverset(6+)(C)r_2O_7^(2-)+SO_4^(2-)+SO_4^(2-)+H_2O`
The colour of a compound is due to either d-d transition or due to charge transfer transitions. In this case both `CrO_4^(2-)` and `Cr_2O_7^(2-)` are coloured due to charge transfer transition.