Which gas is the main constituent of biogas and natural gas? MCQ with Answer and Explanation

Explanation:
In electrolytic refining, impure copper is the anode, pure copper is the cathode, and CuSO₄ acidified with H₂SO₄ is the electrolyte. Copper dissolves from anode and pure copper deposits on cathode. Smelting is reduction with coke.

Explanation:
The carbon-fluorine bond is one of the strongest covalent bonds, making PTFE resistant to attack by chemicals and heat. The fluorine atoms also shield the carbon backbone.

Explanation:
CO₂ is a linear molecule (O=C=O). Although the C=O bonds are polar, the molecule is symmetric, and the dipole moments of the two bonds are equal and opposite, canceling each other out. Thus, the net dipole moment is zero, making it non-polar. HCl, H₂O, and NH₃ are polar.