Which statement correctly describes oxidation and reduction?

Which statement correctly describes oxidation and reduction?

• A. Oxidation is gain of electrons; Reduction is loss of electrons.
• B. Oxidation is loss of electrons; Reduction is gain of electrons.
• C. Both involve gain of electrons.
• D. Both involve loss of electrons.

Answer: (B)

The key idea is that electrons move from the substance being oxidized to the one being reduced. Oxidation is the loss of electrons, while reduction is the gain of electrons. In a redox reaction, one reactant donates electrons and is oxidized, and the other accepts electrons and is reduced. For example, sodium metal loses an electron to become Na+, while chlorine gains that electron to become Cl−. NAD+ gaining electrons to become NADH is another clear case of reduction. That’s why the correct description is that oxidation involves loss of electrons and reduction involves gain of electrons. The other statements misstate the direction of electron transfer or claim both steps involve the same electron fate.

The key idea is that electrons move from the substance being oxidized to the one being reduced. Oxidation is the loss of electrons, while reduction is the gain of electrons. In a redox reaction, one reactant donates electrons and is oxidized, and the other accepts electrons and is reduced. For example, sodium metal loses an electron to become Na+, while chlorine gains that electron to become Cl−. NAD+ gaining electrons to become NADH is another clear case of reduction. That’s why the correct description is that oxidation involves loss of electrons and reduction involves gain of electrons. The other statements misstate the direction of electron transfer or claim both steps involve the same electron fate.