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प्रश्न
The spontaneity means, having the potential to proceed without the assistance of 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.
उत्तर
(iii) Gas expanding to fill the available volume.
(iv) Burning carbon in oxygen to give carbon dioxide.
Explanation:
Gas expands or diffuses in available space spontaneously, e.g., leakage of cooking gas gives smell of ethyl mercaptan spontaneously. Moreover, burning of carbon to \[\ce{CO2}\] is also spontaneous.
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संबंधित प्रश्न
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Match the following processes with entropy change:
| Reaction | Entropy change |
| (i) A liquid vapourises | (a) ∆S = 0 |
| (ii) Reaction is non-spontaneous at all temperatures and ∆H is positive |
(b) ∆S = positive |
| (iii) Reversible expansion of an ideal gas | (c) ∆S = negative |
Assertion (A): A liquid crystallises into a solid and is accompanied by decrease in entropy.
Reason (R): In crystals, molecules organise in an ordered manner.
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