(A) : Colloid is a heterogenous system
(R): Colloidal particles have an enormous surface area per gram as a result of their small size 

Options

A. Both A & R are true, R is the correct explanation of A
B. Both A & R are true, R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true

Answer

To solve the question, we need to analyze both statements (A) and (R) and determine their validity and relationship.

### Step 1: Evaluate Statement (A)
**Statement (A): Colloid is a heterogeneous system.**

- A colloid is indeed a heterogeneous mixture where the particle size is between 1 nanometer (10^-9 m) and 1 micrometer (10^-6 m). In a colloidal system, the dispersed phase (the colloidal particles) is not uniformly distributed throughout the continuous phase (the medium in which they are dispersed). This confirms that statement (A) is true.

### Step 2: Evaluate Statement (R)
**Statement (R): Colloidal particles have an enormous surface area per gram as a result of their small size.**

- Colloidal particles are small, typically ranging from 10^-7 to 10^-9 meters. Due to their small size, they have a large surface area relative to their mass. This means that for a given mass of colloidal particles, the surface area is significantly larger compared to larger particles. Thus, statement (R) is also true.

### Step 3: Analyze the Relationship Between (A) and (R)
- While both statements are true, we need to determine if (R) is the correct explanation for (A). Statement (A) describes the nature of colloids as heterogeneous systems, while statement (R) describes a property of colloidal particles (large surface area due to small size). The large surface area does not directly explain why colloids are heterogeneous; it is a characteristic of the particles themselves.

### Conclusion
- Both statements are true, but (R) does not serve as a correct explanation for (A). Therefore, the correct answer is: **Both A and R are true, but R is not the correct explanation of A.**

### Final Answer
**Option B: Both A and R are true, but R is not the correct explanation of A.**

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