The gas liberated by heating potassium permanganate is:
Oxygen
The explanation for the correct option
(B) Oxygen
Potassium permanganate
Chemical reaction
Hence, gas liberated by heating potassium permanganate is oxygen.
The explanation for the incorrect options
The gas liberated by heating potassium permanganate is oxygen. Hence, options (A), (C), and (D) are incorrect.
Thus, the correct option is (B).