Question

Endothermic reactions are spontaneous even though enthalpy change
is positive (unfavourable). Give reason.
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Answer 1

Answer:

spontaneity of a reaction can be determined in three ways:

1) enthalpy

2) entropy

3) gibbs free energy

thus for reactions which have positive enthalpy can be spontaneous if their entropy factor dominates

entropy is the measure of randomness

thus if we have a reaction like:

ice(solid)>>water(liquid) in this reaction we will have to provide energy thus the enthalpy is positive

but in the very same reaction the randomness of molecules(entropy) is increasing

thus making the overall reaction spontaneous as here entropy dominates enthalpy

Explanation: