Chemistry - Thermochemistry Question with Solution | TestHub
Consider the following isomerization process:
CH2=CH-CH2-CH2-CH=CH2(g) → CH2=CH-CH=CH-CH2-CH3(g)
Which of the following statement(s) is/are true regarding this process? (one or more than one correct)
Options:(select one or more)
Answer:
Solution:
The reactant is 1,5-hexadiene, which has isolated double bonds. The product is 1,3-hexadiene, which is conjugated. Conjugated systems are more stable due to resonance (conjugation) energy.
Therefore, the process is exothermic (statement 'a' is false) because the product is more stable. The magnitude of the enthalpy change, |ΔH|, is equal to the resonance enthalpy of the product (statement 'b' is true).
Since less energy is stored in the more stable isomer, it releases less heat upon combustion to the same products (statement 'c' is true).
Both isomers hydrogenate to form hexane. Consequently, the more stable product releases less heat, meaning the magnitude of its hydrogenation enthalpy is smaller (statement 'd' is false).
The correct answers are (b) and (c).
