Give reasons for the following –

(i) almost 90% of all known compounds are organic in nature.

(ii) it is dangerous to burn methane in an insufficient supply of air.

Choose the correct answer:

The number of C – H bonds in ethane molecule are:

A: Four
B: Six
C: Eight
D: Ten

Name a gaseous hydrocarbon commonly used for welding purposes.

Choose the correct answer:

Unsaturated hydrocarbons undergo

A: substitution reaction
B: oxidation reaction
C: addition reaction
D: none of the above