Choose the correct statements about the coagulation process:
(A) Coagulation makes smaller colloids adhere to each other to form large floc particles. (B) Colloids are continually involved in Brownian motion. (C) Colloids are stable because of their surface charge. (D) Coagulants are preferably trivalent cations. (E) Coagulants are soluble in neutral pH.
Choose the most appropriate answer from the options given below:

Correct option is C

The correct answer is (c) A, B, C, and D only. Here’s an explanation for each statement:
1. (A) Coagulation makes smaller colloids adhere to each other to form large floc particles – Correct. Coagulation causes colloidal particles to clump together to form larger aggregates called flocs.
2. (B) Colloids are continually involved in Brownian motion – Correct. Colloidal particles undergo random motion due to collisions with molecules of the dispersion medium, known as Brownian motion.
3. (C) Colloids are stable because of their surface charge – Correct. Colloids remain stable due to repulsive electrostatic forces caused by their surface charge, which prevents them from aggregating naturally.
4. (D) Coagulants are preferably trivalent cations – Correct. Trivalent cations such as Al³⁺ and Fe³⁺ are effective coagulants because their high charge density neutralizes colloid surface charges efficiently.
5. (E) Coagulants are soluble in neutral pH – Incorrect. Many coagulants, such as aluminum sulfate and ferric chloride, are not completely soluble or effective at neutral pH; their effectiveness can vary with pH conditions.
Information Booster: 1. Coagulation: A process where destabilized colloids aggregate to form flocs, aiding in their removal from suspension.
2. Brownian Motion: Random movement of colloidal particles due to collisions with molecules in the dispersion medium.
3. Surface Charge: Stabilizes colloids by creating repulsive forces between particles.
4. Trivalent Cations: Effective coagulants like Al³⁺ (aluminum ions) and Fe³⁺ (ferric ions) help neutralize colloidal charges.
5. pH Sensitivity: Coagulants work best within specific pH ranges; for example, aluminum sulfate works optimally in slightly acidic conditions (pH 5-6.5).
Additional Knowledge: · Common Coagulants:
· Aluminum Sulfate (Al₂(SO₄)₃)
· Ferric Chloride (FeCl₃)
· Coagulation vs. Flocculation:
· Coagulation neutralizes charges; flocculation causes the formation of larger flocs through gentle mixing.
· Applications: Water treatment, wastewater treatment, and industrial processes.