Reduction potential of potassium is
**Core Concept**
The reduction potential of an ion is a measure of its tendency to gain electrons and be reduced, typically expressed in volts (E0) and measured against a standard hydrogen electrode. In the context of potassium, its reduction potential is of interest as it relates to its role in cellular physiology, particularly in the context of the sodium-potassium pump.
**Why the Correct Answer is Right**
Potassium ions (K+) have a reduction potential of -2.93 volts, which is a measure of their tendency to be reduced to form potassium metal. This value is negative because potassium ions are highly reactive and tend to lose electrons to be reduced. In the body, potassium ions are maintained at a high concentration inside cells, while sodium ions are maintained at a high concentration outside cells, creating an electrochemical gradient that drives the sodium-potassium pump. The reduction potential of potassium is an important parameter in understanding this process.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the reduction potential of potassium is not positive. Potassium ions are highly reactive and tend to lose electrons, which is reflected in their negative reduction potential.
* **Option B:** This option is incorrect because it is a highly positive value, which is not characteristic of potassium ions. Potassium ions have a negative reduction potential due to their high reactivity.
* **Option C:** This option is incorrect because it is a highly negative value, which is not characteristic of potassium ions. While potassium ions do have a negative reduction potential, the correct value is -2.93 volts, not as low as this option suggests.
**Clinical Pearl / High-Yield Fact**
One important clinical correlation is that the reduction potential of potassium is related to its role in the sodium-potassium pump, which is essential for maintaining proper cellular function and electrolyte balance.
**Correct Answer:** -2.93