When steam is passed through red hot coke:

Options

A. `CO_(2)` and `H_(2)` are obtained
B. `CO` and `N_(2)` are formed
C. `CO` and `H_(2)` are obtained
D. petrol gas is obtained

Explanation

**Step-by-Step Solution:**

1. **Identify the Reactants:**
- The reactants in this reaction are red hot coke and steam. Red hot coke is primarily carbon (C), and steam is water (H2O) in its gaseous form.

2. **Write the Reaction:**
- When steam is passed over red hot coke, the reaction can be represented as:
\[ C (s) + H_2O (g) \rightarrow CO (g) + H_2 (g) \]
- Here, carbon reacts with steam to produce carbon monoxide (CO) and hydrogen gas (H2).

3. **Identify the Products:**
- The products of this reaction are carbon monoxide (CO) and hydrogen (H2). This mixture is commonly referred to as "water gas."

4. **Conclusion:**
- Based on the reaction, when steam is passed through red hot coke, the products obtained are carbon monoxide and hydrogen. Therefore, the correct answer is option 3: carbon monoxide and hydrogen.