Choose the correct options, and explain the reason for the correct and incorrect options. Class 9

Choose the correct options, and explain the reason for the correct and incorrect options. Class 9

Question 1.

Choose the correct options, and explain the reason for the correct and incorrect options. Which among the following mixtures show the Tyndall Effect? A mixture of: Class 9

(a) air and dust particles

(b) copper sulfate and water

(c) starch and water

(d) acetone and water

(i) a and b

(ii) b and d

(iii) a and c

(iv) c and d

Answer:

(iii) a and c.

(a) Air and dust particles: This is a colloid - dust particles (1-1000 nm) dispersed in air. Colloids show the Tyndall Effect. CORRECT,

(b) Copper sulfate and water: This is a true solution (particles < 1 nm). True solutions do NOT show the Tyndall Effect. INCORRECT,

(c) Starch and water: Starch forms a colloid in water (starch 4 particles are in the colloid range). Colloids show the Tyndall Effect. CORRECT,

(d) Acetone and water: This is a homogeneous solution. Solutions do NOT show the Tyndall Effect. INCORRECT.