JEE Main 2022 · 26 Jul · Shift 2 · Chemistry Q65

ChemistrySingle correct+4 / -1Question 65 of 90

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Finest gold is red in colour, as the size of the particles increases, it appears purple then blue and finally gold.

Reason R: The colour of the colloidal solution depends on the wavelength of light scattered by the dispersed particles.

In the light of the above statements, choose the most appropriate answer from the options given below.

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.

A is true but R is false.

A is false but R is true.

Answer and worked solution

Official answer: A

Assertion. Finest gold sols are red; larger particles look purple, then blue, then golden. True.

Reason. The colour comes from the wavelength scattered by the particles, which depends on their size. True, and it explains A.

(A)

Topics:Colloids

JEE Main 2022 · 26 Jul · Shift 2, Chemistry question 65