A first order reaction is `40%` completed in 50 minutes. What is the time required for `90%` of the reaction to complete?

Explanation

To solve the problem of how long it takes for a first-order reaction to reach 90% completion, given that it takes 50 minutes to reach 40% completion, we can follow these steps:

### Step 1: Understand the first-order kinetics equation
For a first-order reaction, the relationship between time, rate constant (k), and the extent of the reaction can be expressed using the equation:
\[ t = \frac{2.303}{k} \log \left( \frac{[A_0]}{[A_0 - x]} \right) \]
where:
- \( t \) is the time,
- \( k \) is the rate constant,
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