Which statement correctly describes the relationship between the sign of the standard…

CHEMISTRY · Single correct · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry

Problem

Which statement correctly describes the relationship between the sign of the standard cell potential,

E^\circ_{\text{cell}}

, and the thermodynamic favorability of a redox reaction under standard conditions? (a) A negative

E^\circ_{\text{cell}}

implies the reaction is thermodynamically favored because

\Delta G^\circ

is negative. (b) Only the magnitude of

E^\circ_{\text{cell}}

determines spontaneity; any reaction with

|E^\circ_{\text{cell}}|>0

is thermodynamically favored regardless of sign. (c) A positive

E^\circ_{\text{cell}}

implies the reaction is thermodynamically favored because

\Delta G^\circ

is negative. (d) The sign of

E^\circ_{\text{cell}}

matters only when entropy is negligible; at high temperature even a reaction with

E^\circ_{\text{cell}}<0

can be spontaneous because the

T\Delta S

term can offset a positive

\Delta G^\circ