A colloidal solution is subjected to an electric field. The colloidal particles move toward the anode. In the coagulation of this solution using NaCl, BaCl2, and AlCl3 separately, which one is the correct order of coagulation power?

Question

How many unit particles are present in a BCC (Body-Centered Cubic) unit cell?

Answer 1

Step 1: The colloidal particles migrate to the anode, so they are negatively charged; coagulation therefore needs added cations to neutralize this charge.
Step 2: By the Hardy-Schulze rule, coagulating power of a cation rises steeply with its valency: \( \text{Al}^{3+} \) (from AlCl3) \( \textgreater \) \( \text{Ba}^{2+} \) (from BaCl2) \( \textgreater \) \( \text{Na}^+ \) (from NaCl).
Step 3: Matching this order to the options confirms AlCl3 has the greatest coagulating power, then BaCl2, then NaCl.
This gives the order \( \text{AlCl}_3 \textgreater \text{BaCl}_2 \textgreater \text{NaCl} \).

Answer 2

Since the sol particles carry a negative charge (they move toward the anode), the coagulating ion in each electrolyte is the cation. Let's rank each electrolyte by its effective cation charge.

NaCl: Supplies Na\(^+\), a monovalent cation. Being singly charged, it is the least efficient at neutralizing the negative sol and therefore has the weakest coagulating power of the three.
BaCl2: Supplies Ba\(^{2+}\), a divalent cation. It neutralizes the negative charge more efficiently than Na\(^+\) but less efficiently than a trivalent ion.
AlCl3: Supplies Al\(^{3+}\), a trivalent cation, giving it by far the strongest coagulating power of the three for this negatively charged sol, consistent with the Hardy-Schulze rule that coagulating power grows very rapidly with the charge of the flocculating ion.

Ranking from strongest to weakest coagulant gives AlCl3, then BaCl2, then NaCl.

Therefore, the correct answer is AlCl3 \( \textgreater \) BaCl2 \( \textgreater \) NaCl.

Answer 3

Since the sol particles carry a negative charge (they move toward the anode), the coagulating ion in each electrolyte is the cation. Let's rank each electrolyte by its effective cation charge.

NaCl: Supplies Na\(^+\), a monovalent cation. Being singly charged, it is the least efficient at neutralizing the negative sol and therefore has the weakest coagulating power of the three.
BaCl2: Supplies Ba\(^{2+}\), a divalent cation. It neutralizes the negative charge more efficiently than Na\(^+\) but less efficiently than a trivalent ion.
AlCl3: Supplies Al\(^{3+}\), a trivalent cation, giving it by far the strongest coagulating power of the three for this negatively charged sol, consistent with the Hardy-Schulze rule that coagulating power grows very rapidly with the charge of the flocculating ion.

Ranking from strongest to weakest coagulant gives AlCl3, then BaCl2, then NaCl.

Therefore, the correct answer is AlCl3 \( \textgreater \) BaCl2 \( \textgreater \) NaCl.

A colloidal solution is subjected to an electric field. The colloidal particles move toward the anode. In the coagulation of this solution using NaCl, BaCl2, and AlCl3 separately, which one is the correct order of coagulation power?

Show Hint

The Correct Option is D

Approach Solution - 1

Approach Solution -2

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