Identify the statement which is incorrect w.r.t. surface phenomenon.

Options

A. A sol, prepared by adding excess `AgA_3` solution in KI solution when subjected to electro-phoresis will show coagulation near cathode
B. The conductivity of a soap solution decreases steeply at CMC
C. Tyndall effect will be more prominent in gold solution as compared to rubber solution
D. Extent of physisorption increases with increase in temperature initially and then decreases with temperature

Explanation

To determine the incorrect statement regarding surface phenomena, we will analyze each statement one by one.

### Step 1: Analyze Statement 1
**Statement:** A soil prepared by adding excess of AgNO3 solution in KI when subjected to electrophoresis will show coagulation near the cathode.

**Analysis:** When AgNO3 is added to KI, Ag+ ions react with I- ions to form AgI, which is a precipitate. The excess I- ions will lead to the formation of a negatively charged colloidal solution of AgI. During electrophoresis, negatively charged particles migrate towards the anode, while positively charged particles move towards the cathode. Therefore, coagulation will occur near the cathode.

**Conclusion:** This statement is correct.
...