For a reaction taking place in a container in equilibrium with its surroundings, the effect of temperature on its equilibrium constant Kin terms of change in entropy is described by

Options

A. With increase in temperature, the value of K for exothermic reaction decreases because the entropy change of the system is positive
B. With increase in temperature, the value of K for endothermic reaction increases because unfavourable change in entropy of the surroundings decreases
C. With increase in temperature, the value of K for endothermic reaction increases because the entropy change of the system is negative
D. With increase in temperature, the value of K for exothermic reaction decreases because favourable change in entropy of the surroundings decreases

Answer

bd

Explanation

`(DeltaG)/(DeltaV) = -RT ln K, DeltaG^(@) = DeltaH^(@) - TDeltaS^(@)`
`-RT ln K = DeltaH^(@) - TDeltaS^(@), ln K = -(DeltaH^(@)/R.1/T + (DeltaS^(@))/R)`
`DeltaH^(@) lt 0, DeltaS^(@) gt 0 rArr K` decreases with increase in T:
`DeltaH^(@) gt 0, DeltaS^(@) gt 0 rArr K` increases with increase in T
`DeltaH^(@) gt 0, DeltaS^(@) lt 0 rArr K` decreases with increases in T.
`DeltaH^(@) lt 0, DeltaS^(@) gt 0 rArr K` decreases with increases in T.
`DeltaS_("surr") =(-q_("sys"))/T_("surr")`
`DeltaS_("surr")` favourable means `DeltaS_("surr")` is positive while `DeltaS_("surr")` unfavourable means `DeltaS_("surr")` is negative.
value of K increases with increases in temperature for endothermic reaction it means reaction shift toward forward direction because of unfavourable change in entropy of the surrounding decreases. Similarly if value of K for exothermic reaction decreses with increases in temperature it means reaction shift toward backward direction due to decreases in favourable change in entropy for surrounding