Question

The first organic compound in primordial earth was

• A. Carbon dioxide
• B. Methane
• C. Carbon monoxide
• D. Ethylene

Answer 1

Answer: (A), (B)

The correct options are
A Methane
B Carbon dioxide

Earth is estimated to be formed about 4.5 billion years ago from the leftover dust and gases of the sun. Early earth didn't have any atmosphere. The surface of the earth was in molten state which after cooling resulted in a huge emission of carbon dioxide, water vapours, methane and ammonia. UV rays from the sun reacted with water vapours and this resulted in the formation of hydrogen and oxygen. Hydrogen is lighter so it escaped and oxygen combined with ammonia and methane to form carbon dioxide, water and carbon dioxide.

Thus the composition of the early atmosphere of the earth was carbon dioxide, nitrogen gas, water vapours, hydrogen gas and compounds having hydrogen atoms bonded to other light elements such as carbon, sulphur etc., that produced hydrogen sulphide, ammonia and methane.

Hence, both options A and B are correct.

So, the correct answer is 'Carbon dioxide' and 'methane'.