Answer: The correct answer is water freezing into ice.
Step-by-step explanation:
Entropy is defined as the randomness and disorderliness of the molecules based on the number of different arrangements that are available to them in a given system. It is a thermodynamic function which is represented by the symbol "S".
More the randomness, more will be the entropy and more away will be the particles because there will be no order in the system and vice versa.
From the given options:
1. Burning natural gas: In this process, energy is being provided which results in the movement of the particles and further increases the randomness of the particles and hence, increases the entropy.
2. Water freezing into ice: In this process, energy is being released which results in the orderly arrangement of the particles and hence, the entropy of the system decreases.
3. Water evaporating on heating: In this process, energy is being provided which results in the movement of the particles and further increases the randomness of the particles and hence, increases the entropy.
4. Dry ice sublimating: In this process, solid is getting converted to ice directly which requires energy. This energy results in the movement of the particles which increases the randomness of the particles. Hence, the entropy of the system increases.
From the above information, the correct answer is water freezing into ice.