In which of the following reactions, standard reaction entropy change `(Delta S^(@))` is positive and standard Gibb's energy `(Delta G^(@))` decreases sharply with increasing temperature ?

Options

A. `(1)/(2) C("graphite") + (1)/(2)O_(2)(g) rarr (1)/(2)CO_(2)(g)`
B. `C("graphite") + (1)/(2)O_(2)(g) rarr CO_(2)(g)`
C. `CO("graphite") + (1)/(2)O_(2)(g) rarr CO_(2)(g)`
D. `Mg(s) + (1)/(2)O_(2)(g) rarr MgO(s)`

Answer

B

Explanation

`C(s) + (1)/(2) O_(2)(g) rarr CO(g)` Since `Delta n_(g) (1 - (1)/(2)) = + ve`, `Delta S` is +ve
`Delta G = Delta H - T delta S`
Since, `Delta S` is +ve, increase in temperature will make `T Delta S` more negative and `Delta G` will decrease.