Match List-I with List-II
| LIST-I | LIST-II |
| A. Hardy-Schulze rule | I. Hardening of leather |
| B. Tyndall effect | II. Coagulation of colloids by electrolytes |
| C. Cottrell precipitator | III. Scattering of light |
| D. Tanning | IV. Removal of pollutants from industrial waste gases |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A)-(II), (B)-(III), (C)-(IV), (D)-(I)
A. Hardy-Schulze rule — This matches II. Coagulation of colloids by electrolytes. The greater the valence of the oppositely charged ion of the electrolyte, the greater its power to coagulate the sol.
B. Tyndall effect — This matches III. Scattering of light. Colloidal particles scatter light, so the path of a beam through a sol becomes visible.
C. Cottrell precipitator — This matches IV. Removal of pollutants from industrial waste gases. The charged smoke and dust particles in chimney gases are neutralised and settle on the charged plates.
D. Tanning — This matches I. Hardening of leather. The positively charged colloidal particles of animal hide are mutually coagulated by the negatively charged particles of tannin.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.