Write all the chemical reactions involved in the manufacture of sulphuric acid by contact process. 

Explanation

To manufacture sulfuric acid (H₂SO₄) by the contact process, several chemical reactions take place. Here are the steps involved along with their respective chemical equations:

### Step 1: Conversion of Sulfur to Sulfur Dioxide
In the first step, sulfur (S) is oxidized to sulfur dioxide (SO₂) by reacting with oxygen (O₂):

\[ S (l) + O_2 (g) \rightarrow SO_2 (g) \]
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