Question

Particles of Substance X are dispersed in water to form a colloid. Which describes the electrical charges on the particles of Substance X?

All the particles carry the same charge, which could be either positive or negative.

Each particle carries a charge that is slightly different from the other particles.

Half of the particles carry a positive charge; the other half carry a negative charge.

All the particles are uncharged, or electrically neutral.

Answer 1

The correct answer is option A.

All the particles carry the same charge, which could be either positive or negative.

All the particles of substance X will have same charge on its surface, which is balanced by the oppositely charged ions in the water.

For example, soap solution (sodium palmitate) dissociates into ions:

C₁₅H₁₁COONa --> C₁₅H₁₁COO⁻ + Na⁺

The cations (Na⁺) passes into the water while the anions (C₁₅H₁₁COO⁻) form aggregates or colloids.