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

Choose the correct answer:

The functional group present in acetic acid is

A: Ketonic C = O
B: Hydroxyl - OH
C: Aldehydic – CHO
D: Carboxyl – COOH

Select the correct answer from the choices given :

(i) The catalyst used for conversion of ethene to ethane is commonly ………….. [nickel/iron/cobalt]

(ii) Acetaldehyde when oxidized with acidified potassium dichromate, forms ………….. [ester/ethanol/acetic acid]

(iii) Ethanoic acid reacts with ethanol in presence of conc. H₂SO₄, so as to form a compound and water. The chemical reaction which takes place is called ………….. [dehydration/hydrogenation/esterification]