For a reaction,
`CaCO_(3(s)) rarr CaO_((s))+CO_(2(g))`
`Delta_(f)H^(@)(CaO)=-"631.1 kJ mol"^(-1)`
`Delta_(f)H^(@)(CO_(2))=-"393.5 kJ mol"^(-1) and`
`Delta_(f)H^(@)(CaCO_(3))=-"1206.9 kJ mol"^(-1)`
Which of the following is a correct statement?

Options

A. Increase
B. decreases
C. no effect
D. both a & b

Answer

A

Explanation

Given that
`triangle_(f) H^(oplus) [CaO(s)]=-635.1" kJ mol"^(-1)`
`triangle_(f) H^(oplus) [CO_2(g)]=-393.5" kJ mol"^(-1)`
`triangleH^(oplus) [CaCO_(3) (s)]=-1206.9" kJ mol"^(-1)` in the reaction, `CaCO_(3) (s) Leftrightarrow CaO(s)+CO_(2) (g)`
`triangle_(f) H^(oplus)=triangle_(f)H^(oplus) [CaO(s)]+triangle_(f) H^(oplus) [CO_(2) (g)]`
`-triangle_(f) H^(oplus) [CaCO_(3) (s)]`
`triangle_(f) H^(oplus)=-635.1+(-393.5)-(-1206.9)=178.3"kJ mol"^(-1)`
Because `triangleH` value is positive, so the reaction is endothermic. Hence, according to Le-Chateller.s principle, reaction will proceed in forward direction on increasing temperature thus, the value of equilibrium constant for the reaction increases.