Q24 · CSIR NET Chemistry, June 2013
Paper: CSIR NET June 2013 · Subject: Physical Chemistry · Chapter: Surface Chemistry · Topic: Surface Tension · Marks: 2 · Difficulty: Medium
"Colloids are thermodynamically unstable with reference to bulk but kinetically stable". Identify the correct pair
| Statements | Reasons |
|---|---|
| (A) thermodynamically unstable | (C) interfacial surface tension |
| (B) kinetically stable | (D) electrical double layer |
(a)(A) $\leftrightarrow$ (D) and (B) $\leftrightarrow$ (C)
(c)(A) $\leftrightarrow$ (C) and (B) $\leftrightarrow$ (C)
(b)(A) $\leftrightarrow$ (C) and (B) $\leftrightarrow$ (D)
(d)(A) $\leftrightarrow$ (D) and (B) $\leftrightarrow$ (D)
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
The large interfacial (surface) free energy makes colloids thermodynamically unstable, and the electrical double layer repulsion keeps them kinetically stable: A ↔ C, B ↔ D.
Study loop for Surface Chemistry