Which of these gases were not used by Stanley Miller in his electric discharge experiment ?

Options

A. Methane
B. Hydrogen
C. Water vapour
D. Nitrogen

Answer

To solve the question of which gas was not used by Stanley Miller in his electric discharge experiment, we can follow these steps:

### Step 1: Understand the Experiment
Stanley Miller conducted an experiment to simulate the conditions of early Earth and test the theory of chemical evolution. He created a reducing atmosphere in a closed flask.

**Hint:** Recall the purpose of Miller's experiment and the conditions he aimed to replicate.

### Step 2: Identify the Gases Used
In Miller's experiment, the gases that were used included:
- Methane (CH₄)
- Hydrogen (H₂)
- Water vapor (H₂O)
- Ammonia (NH₃)

**Hint:** Think about the composition of the early Earth's atmosphere and the gases that would have been present.

### Step 3: Analyze the Options
The question provides the following options:
1. Methane
2. Hydrogen
3. Water vapor
4. Nitrogen

From the gases listed above, we can see that Methane, Hydrogen, and Water vapor were indeed used in the experiment.

**Hint:** Compare each option with the list of gases used in the experiment.

### Step 4: Identify the Gas Not Used
The only gas from the options provided that was not used in Miller's experiment is Nitrogen (N₂).

**Hint:** Eliminate the gases that were confirmed to be part of the experiment to find the one that was not used.

### Conclusion
The gas that was not used by Stanley Miller in his electric discharge experiment is **Nitrogen**.

**Final Answer:** Option 4 - Nitrogen