Question:
The spontaneity means, having the potential to proceed without the assistance
of an external agency. The processes which occur spontaneously are
(i) flow of heat from colder to warmer body.
(ii) gas in a container contracting into one corner.
(iii) gas expanding to fill the available volume.
(iv) burning carbon in oxygen to give carbon dioxide.
Solution:
Option (iii) gas expanding to fill the available volume and (iv) burning carbon in oxygen to give carbon dioxide are the answers.