The indicator methylene blue:
-Is blue in an anaerobic environment
-Is blue when oxygen is present
-Is pink when oxygen is present
-Absorbs excess oxygen
The correct statement is:
- Is blue in an anaerobic environment.
The indicator methylene blue is a commonly used dye in various laboratory and clinical applications. It has different color changes depending on the presence or absence of oxygen.
1. Blue in an anaerobic environment: Methylene blue is blue in the absence of oxygen. This means that in a closed system or an environment where oxygen is limited, methylene blue will retain its blue color.
2. Blue when oxygen is present: Methylene blue turns colorless or loses its blue color in the presence of oxygen. This occurs due to a chemical reaction with oxygen molecules.
3. Pink when oxygen is present: It is not accurate to say that methylene blue turns pink when oxygen is present. Normally, it becomes colorless or loses its blue color.
4. Absorbs excess oxygen: Methylene blue does not absorb excess oxygen in the same way a sponge absorbs water. Instead, it undergoes a chemical reaction with oxygen that causes its color to fade.
To observe the color change of methylene blue in the presence or absence of oxygen, a simple experiment can be conducted.
1. Take a small amount of methylene blue solution and place it in a test tube or a container.
2. In one test tube, introduce an anaerobic environment by sealing it completely, preventing the entry of oxygen. The blue color of methylene blue will remain unchanged.
3. In another test tube, leave it open to the air, allowing oxygen to be present. Over time, the methylene blue will slowly lose its blue color and become colorless or fade.
It is important to note that the color change of methylene blue is reversible. If the oxygen is removed or decreased, the blue color may reappear.
The indicator methylene blue behaves in the following way:
1. It turns blue in an anaerobic environment: Methylene blue is commonly used as an indicator to identify the presence of oxygen. In the absence of oxygen, it remains blue in color.
2. It is blue when oxygen is present: In the presence of oxygen, methylene blue retains its blue color. This property allows it to be used as an indicator for the presence of oxygen in certain experiments or applications.
3. It does not turn pink when oxygen is present: Methylene blue does not change to a pink color when oxygen is present. Its color remains blue in both aerobic (oxygen present) and anaerobic (oxygen absent) environments.
4. It absorbs excess oxygen: Methylene blue can also act as an oxygen scavenger. It has the ability to react with and absorb excess oxygen, which can be useful in certain circumstances where the presence of oxygen needs to be minimized or removed.
In summary, methylene blue is blue in an anaerobic environment, stays blue in the presence of oxygen, does not turn pink when oxygen is present, and has the capacity to absorb excess oxygen.