When ethene is mixed with hydrogen in the presence of a platinum catalyst, hydrogen adds across the double bond to form ethane. At room temperature, the reaction goes to completion.Predict the signs of for this reaction. Explain these signs in terms of bonding and freedom of motion.
Ethane undergoes catalytic reduction in presence of hydrogen to form ethane.
The reaction is as follows:
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In the above reaction, two molecules react to give one molecule. So, the reactants have more degree of freedom than the products. Thus, the entropy change is negative.
Since the entropyis negative, the term becomes positive.
The above reaction is much favourable. It means that the free energy change is large negative.
The entropy is negative, and the free energy is negative. So, the enthalpy of the reaction must be negative.