Question

For the reaction : ${Cl}_2\left(g\right)⟶2Cl\left(g\right),$ _________

• A. $\Delta$ H is positive, $\Delta$ S is positive
• B. $\Delta$ H is positive, $\Delta$ S is negative
• C. $\Delta$ H is negative, $\Delta$ S is negative
• D. $\Delta$ H is negative, $\Delta$ S is positive

Answer 1

Answer: (C)

$\Delta$ H is negative, $\Delta$ S is negative

$\Delta$H and $\Delta$S are negative.

The given reaction represents the formation of chlorine molecule from chlorine atoms.

Here, the bond formation is taking place. Therefore, energy is being released. Hence, ∆H is negative.

Also, two moles of atoms have more randomness than one mole of a molecule. Since spontaneity is decreased, ∆S is negative for the given reaction.

Hence option C is the correct answer.