Question

Observe the following statements: I. Micelles have both lyophilic and lyophobic parts II. Starch in water is an example for multimolecular colloid III. The CMC of a soap is \(10^{-3}\,\text{mol L}^{-1}\). It can form a micelle when its concentration is less than \(10^{-3}\,\text{mol L}^{-1}\) IV. Gold sol can be prepared by Bredig's Arc method Choose the correct statements.

• A. I, II, III, IV
• B. I, II, IV only
• C. I, IV only
• D. II, III only

Hint:

Starch = Macromolecular colloid. Micelles form only above CMC. Gold sol is prepared by Bredig's arc method.

Answer 1

The Correct Option is C

Step 1: Check Statement I Micelles consist of: Hydrophilic (water-loving) head and Hydrophobic (water-repelling) tail Thus, they have both lyophilic and lyophobic parts. \[ \boxed{\text{Statement I is correct}} \]

Step 2: Check Statement II Starch in water is an example of: Macromolecular colloid not multimolecular colloid. \[ \boxed{\text{Statement II is incorrect}} \]

Step 3: Check Statement III Micelles form only when concentration is: greater than CMC Given CMC: \[ 10^{-3}\,\text{mol L}^{-1} \] The statement says less than CMC, which is wrong. \[ \boxed{\text{Statement III is incorrect}} \]

Step 4: Check Statement IV Gold sol is prepared by: Bredig's Arc Method which is a dispersion method. \[ \boxed{\text{Statement IV is correct}} \] Correct statements are: \[ I,\ IV \] \[ \boxed{\text{I, IV only}} \] Therefore, the correct answer is: \[ \boxed{(C)} \]