The minimum concentration of an electrolyte in millimoles per litre which is required to cause the precipitation of a sol in two hours is called as:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Coagulating value
Electrolytes coagulate a sol by neutralising the charge on its particles; the minimum amount of electrolyte that does it in a fixed time is its coagulating value. Flocculation is the name of the process itself (coagulation); its minimum concentration is the flocculation value.
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.
NCERT (Pre-rationalised edition, 2022-23):
Coagulation or Precipitation – …
