Question

The gas which burns with blue flame is:
A. $CO$
B. ${O_2}$
C. ${N_2}$
D. $C{O_2}$

Answer 1

Hint: Firstly we should be clear that each gas has a specific type of flame depending on the nature of combustion and the products formed and so does all these gases which are given in the option. Now in the question it has been asked about the blue flame. Now only carbon monoxide has the tendency to give blue flame on the combustion.

Complete step by step answer:
In the given question we have to find out the correct gas which will provide the blue flame on the proper combustion. Now we have to give the proper idea regarding the combustion of the gas which is carbon monoxide.
Here we have to firstly take many of the things into the account:
-For the given gas, Oxygen and an ignition source are required for combustion to occur. The amount of oxygen should be appropriate and adequate in order of the complete combustion. Now we know that the hydrogen is a gas that burns with the pale blue flame that is nearly invisible in daylight.
-So now apart from that, In the presence of oxygen including atmospheric concentrations carbon monoxide burns with a blue flame producing carbon dioxide.

So the correct option would be option A, $CO$.

Note: Carbon monoxide is a colorless, odorless, and tasteless flammable gas that is slightly less dense than air. It is toxic to animals that use hemoglobin as an oxygen carrier (both invertebrate and vertebrate) when encountered in concentrations above about \[35{\text{ }}ppm\], although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal biological functions.