Mixing of positively charged colloidal solution with negatively charged colloidal solution brings __________. The decreasing order of coagulating power of `Na^(+), Ba^(2+) and Al^(3+)` for negatively charged colloidal solution is ________ .

Options

A. mutual coagulation , `Na^(+) gt Ba^(2+) gt Al^(3+)`
B. mutual coagulation , `Al^(3+) gt Ba^(2+) gt Na^(+)`
C. coagulation , `Na^(+) gt Ba^(2+) gt Al^(3+)`
D. Peptization , `Al^(3+) gt Ba^(2+) gt Na^(+)`

Explanation

To solve the question, we need to analyze two parts:

1. The effect of mixing a positively charged colloidal solution with a negatively charged colloidal solution.
2. The decreasing order of coagulating power of the ions Na⁺, Ba²⁺, and Al³⁺ for negatively charged colloidal solutions.

### Step 1: Understanding the Mixing of Colloidal Solutions
When a positively charged colloidal solution is mixed with a negatively charged colloidal solution, they will neutralize each other due to the opposite charges. This process is known as **coagulation**.

### Step 2: Identifying the Type of Coagulation
The mixing of these two oppositely charged colloidal solutions results in a phenomenon called **mutual coagulation**. This occurs because the positive and negative charges attract each other, leading to the aggregation of colloidal particles.

### Step 3: Coagulating Power of Ions
The coagulating power of ions depends on their valency. Generally, ions with higher valency have greater coagulating power.

- **Al³⁺** has a valency of 3.
- **Ba²⁺** has a valency of 2.
- **Na⁺** has a valency of 1.

### Step 4: Arranging the Coagulating Power
Based on the valency, we can arrange the ions in order of their coagulating power:
- Al³⁺ > Ba²⁺ > Na⁺

### Conclusion
Thus, the answers to the question are:
1. Mixing of positively charged colloidal solution with negatively charged colloidal solution brings **mutual coagulation**.
2. The decreasing order of coagulating power of Na⁺, Ba²⁺, and Al³⁺ for negatively charged colloidal solution is **Al³⁺ > Ba²⁺ > Na⁺**.

### Final Answer
1. Mutual coagulation
2. Al³⁺ > Ba²⁺ > Na⁺

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