On passing 10.0 L of a gaseous mixture of `NO_(2)` and `N_(2)` at STP, through an `NaOH` solution, a mixture of `NaNO_(2)` and `NaNO_(3)` is formed 6.32 g of `KMnO_(4)` is required to oxidise above `NaNO_(2)` in `H_(2)SO_(4)` medium. Determine the percentage by mass of gaseous mixture `(N_2` does not react with `NaOH`)

Explanation

To solve the problem step by step, we will follow the information provided in the question and the video transcript.

### Step 1: Write the balanced chemical equation
The reaction of nitrogen dioxide (NO₂) with sodium hydroxide (NaOH) produces sodium nitrite (NaNO₂) and sodium nitrate (NaNO₃):
\[ 2 \text{NO}_2 + 2 \text{NaOH} \rightarrow \text{NaNO}_2 + \text{NaNO}_3 + \text{H}_2\text{O} \]

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