Answer:
The correct order of lighting a Bunsen Burner from the options is:
1. Clear the area of anything flammable, such as liquids, hair, etc.
2. Use a strike lighter to light the flame.
3. Turn on the gas supply to the Bunsen burner.
4. Adjust the air flow to control the size of the flame.
5. Close the air supply on the Bunsen burner.
Explanation:
First of all, I want you to note that the process or standard operating procedure for using a Bunsen burner, is to ensure safety of both the user and the laboratory. Hence the steps should be followed in order as listed below:
1. First clear out any flammable material around the burner, so that when it is lit, nothing will be ignited to start a fire. This is important because if clearing is done after lighting the burner, it might already be too late.
2. and 3. a strike lighter is lit first before turning on the gas supply. If the gas supply is turned on first before lighting the burner, then there will be reservoir gas in the atmosphere around the burner and once the strike lighter is lit, it may cause an explosion as gas is highly flammable. Hence the lighter is lit first then the gas supply is turned on slowly until the burner is ignited
4. next, the airflow is adjusted slowly to get a desired flame size. Ideally, when the burner produces a blue flame, adjustments should be stopped.
5. Finally after the use of the burner, the air supply should be closed tightly to ensure that there is no further leakage of gas.
It addition to these, it should be noted that the gas cylinder that supplies the gas to the burner, should not be in the same room or space as the burner, and a fire extinguisher should be readily available in the room where the burner is used, should there be any emergencies.