Question

For the gas phase reaction
`PCl_(5)rarrPCl_(3)(g)+Cl_(2)(g)`
which of the following conditions are correct?
A. `Delta H = lt` and `Delta S lt 0`
B. `Delta H gt 0` and `Delta S gt 0`
C. `Delta H lt 0` and `Delta S lt 0`
D. `Delta H gt 0` and `Delta S lt 0`

Answer 1

Correct Answer - B
The reaction involves the dissociation of `PCl_(5)`, an energy consuming. Thus, `Delta H` is positive `(gt 0)`. During the course of reaction, there is an increase in the number of gaseous species and, hence `Delta S` is also positive `(gt 0)`.