when will a molecule be assigned a negative standard reduction potential
Reduction potential Any system or environment that accepts electrons from a normal hydrogen electrode is a half cell that is defined as having a positive redox potential; any system donating electrons to the hydrogen electrode is defined as having a negative redox potential.   E h   {\displaystyle E_{h}}  is measured in millivolts (mV). A high positive   E h   {\displaystyle E_{h}}  indicates an environment that favors oxidation reaction such as free oxygen. A low negative   E h   {\displaystyle E_{h}}  indicates a strong reducing environment, such as free metals.