The correct statement(s) about surface properties is (are)

Options

A. Cloud is an emulsion type of colloid in which liquid is dispersed phase and gas is dispersion medium
B. Adsorption is accompanied by decrease in enthalpy and decrease in entropy of the system
C. The critical temperatures of ethane and nitrogen are 563 K and 126 K, respectively. The adsorption of ethane will be more than that of nitrogen on same amount of activated charcoal at a given temperature
D. Brownian motion of colloidal particles does not depend on the size of the particles but depends on viscosity of the solution

Explanation

To determine the correct statements about surface properties, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: "Cloud is an emulsion type of colloid in which liquid is dispersed where and gas is dispersed in medium."**
- **Analysis**: A cloud is formed by tiny water droplets suspended in the air (gas). This is a case of a liquid dispersed in a gas, which classifies it as an aerosol, not an emulsion. An emulsion involves two immiscible liquids.
- **Conclusion**: This statement is **incorrect**.

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