Statement-1 : At low temperature, ΔH is the dominant factor for spontaneity of a reaction.
Statement-2 : The opposing factor TΔS remains very small, at low temperature.
a)
Statement-2 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1.
b)
Statement-2 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-2.
c)
Statement-2 is True, Statement-2 is False.
d)
Statement-1 is False, Statement-2 is True.
Correct answer is option 'A'. Can you explain this answer?

Question

Statement-1 : At low temperature, &Delta;H is the dominant factor for spontaneity of a reaction.Statement-2 : The opposing factor T&Delta;S remains very small, at low temperature.a)Statement-2 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1.b)Statement-2 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-2.c)Statement-2 is True, Statement-2 is False.d)Statement-1 is False, Statement-2 is True.Correct answer is option 'A'. Can you explain this answer?

Answer

The Gibbs free energy for a reaction is given by, ∆G = ∆H - T∆S. Based on the sign of G the following can be concludes from any reaction,

∆G < 0 : the reaction is spontaneous

∆G = 0 : the reaction is at equilibrium

∆G > 0 : The reaction is non-spontaneous

So, for a reaction to be spontaneous the necessary condition is that ∆G < 0. Now at low temperatures, the effect of T∆S on the sign of G will be negligible. So, the spontaneity of reaction is directly dependent on ∆H. If ∆H > 0 then ∆G > 0 and vice-versa. So, the given statement is correct and Reason is the correct explanation for it.

Answer

The particles in a substance have less kinetic energy and move more slowly.
Statement-2 : At high temperature, the particles in a substance have more kinetic energy and move more quickly.

Both statements are correct.

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