Through the two ends of a glass tube of length `200cm` hydrogen chloride gas and ammonia are allowed to enter At what distance ammonium chloride will first appear ? .

Explanation

To solve the problem of determining the distance from one end of a glass tube where ammonium chloride will first appear when hydrogen chloride (HCl) and ammonia (NH3) are allowed to enter from opposite ends, we can use Graham's law of diffusion. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Understanding the Setup**:
- We have a glass tube of length 200 cm.
- HCl gas enters from one end and NH3 gas enters from the other end.

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