Question

Which of the following pairs are correct?

• A. Saturated compounds - yellow or sooty flame, unsaturated compounds – clean or blue flame.
• B. Saturated compounds - clean or blue flame, unsaturated compounds – yellow flame.
• C. Saturated compounds and unsaturated compounds both give yellow or sooty flame on complete combustion.
• D. Saturated compounds and unsaturated compounds both give clean or blue flame.

Answer 1

The correct option is B Saturated compounds - clean or blue flame, unsaturated compounds – yellow flame.

The correct pair:
Saturated compounds - Clean or blue flame.
Unsaturated compounds – Yellow or sooty flame.

This change in colour of flame happens due to the incomplete combustion of carbon compounds. The saturated compounds on complete combustion give clean or blue flame and on incomplete combustion give yellow or sooty flame. The saturated compounds on burning give yellow or sooty flame.