Question

7. a)
Sujit was performing an experiment in the laboratory. He collected four substances
I, II,III and IV and kept all of them in contact with air at room temperature.
He observed that substance III suddenly bursts into flames. Then, he heated I, II and
IV and found out that while I and II catch fire, substance IV does not. However
substance IV catches fire on prolonged heating. Which substance undergoes
spontaneous combustion in Sujit's experiment?​

Answer 1

Answer:

iii) goes of instant flame due to presence of oxygen

i and ii burn after provided a heating source

so my answer is (iii)