To answer the question of what would be the biggest problem for the student in collecting methane gas using method 3, let's first analyze the properties of methane and the implications of method 3.
1. Properties of Methane:
- Solubility in Water: Methane is not soluble in water.
- Density Compared to Air: Methane is less dense than air.
- Smell: Methane has no smell.
2. Method 3:
While the specific details of method 3 are not provided here, likely, method 3 involves the displacement of water due to the context provided about gases' properties. This means that the gas is collected by displacing water in an inverted container.
3. Challenges with Collecting Methane Using Method 3:
- Getting the Methane to Stay in the Flask:
Since methane is less dense than air, it will tend to rise and escape when the container is opened or if there's any gap. This makes it difficult to keep the methane in the flask.
- Knowing When the Flask is Full:
This could be a concern, but it is less challenging compared to keeping the gas within the flask, especially since methane is odorless and colorless.
- Preventing Methane from Igniting:
While methane is flammable, this concern is secondary to simply collecting and containing it in the flask.
- Avoiding the Strong Smell of Methane:
Methane has no smell, so this option is irrelevant.
Given the properties of methane and the likely method of collection (displacement of water where methane would naturally rise and possibly escape because it is less dense than air), the most significant issue the student would face is:
(A) Getting the methane to stay in the flask.
Thus, the biggest challenge for the student would be ensuring that the methane gas, being less dense than air, does not escape from the flask.
