Question

. When burning sulphur is taken into the cylinder of oxygen, it burns with a brilliant blue
flame. Name the gas produced. What happens when this gas reacts with water. Support your
answer with the equation.

Answer 1

Answer:

Sulfur is only mildly flammable under normal atmospheric conditions, but in pure oxygen, it burns with a very nice blue flame. The products of the combustion are sulfur dioxide and sulfur trioxide:

S(s) + O2(g) ——> SO2(g)

2S(s) + 3O2(g) ——> 2SO3(g)

These substances react with water in the air to produce sulfurous and sulfuric acid, respectively:

SO2(g) + H2O(g) ——> H2SO3(g) [sulfurous acid]

SO3(g) + H2O(g) ——> H2SO4(g) [sulfuric acid]

This can be demonstrated by quenching the burning sulfur with a small amount of distilled water, and adding an appropriate acid-base indicator, such as methyl orange.

In the following demonstration, a small amount of sulfur is placed in a deflagrating spoon, heated in a Bunsen burner until it begins to burn, and then lowered into a jar of pure oxygen. The sulfur then flares up into a much brighter blue flame, and eventually begins to throw off fumes of sulfur dioxide and trioxide.