Question

The gas that burns in oxygen with a green flame is:
A.ammonia
B.sulphur dioxide
C.chlorine
D.\[{H_2}S\]

Answer 1

Hint:We know that in the presence of oxygen usually ammonia does burn. But at a very high temperature and in presence of the catalyst, ammonia burns to give greenish yellow flame.

Complete answer:
The combustion of ammonia (\[N{H_3}\]) proceeds to yield nitrogen gas and water and with the use of catalyst and under correct conditions of temperature, ammonia reacts with oxygen to produce nitric oxide which is oxidized to nitrogen dioxide (NO) and is used in the synthesis of nitric acid. The gas evolved is ammonia gas (\[N{H_3}\]) which on burning in the oxygen gives a greenish yellow flame.
Ammonia does not burn readily or sustain combustion, except under narrow fuel to air mixtures of \[15\% \]to \[25\% \] air. When it is mixed with oxygen, it burns with a pale yellowish-green flame. At the high temperature and in the presence of a suitable catalyst, ammonia is decomposed into its constituent elements.
The colour of the flame is due to the formation of nitrogen oxide (NO) as shown in the following reaction below:
\[4N{H_3} + 3{O_2} \to 2NO + 6{H_2}O\]
Hence, we know that the gas that burns in oxygen with a green flame is ammonia (\[N{H_3}\])

Therefore, the correct answer is option (A).

Note:
A slightly rich mixture that “greens” the blue part of the flame might mean a bit more carbon monoxide coming off your stove top, but it shouldn't be dangerous. Also, the green flame can be caused by copper salts or corroded copper parts contaminating the flame with copper ions.