When testing electrodes for polarity, the negative electrode will create which of the following at its surface?

• A. A positive charge
• B. The release of cations
• C. A deficiency of electrons
• D. An excess of electrons

Answer: (D)

Verified step by step guidance

1. Understand that an electrode's polarity refers to whether it is negatively or positively charged during an electrochemical process.
2. Recall that the negative electrode, also called the cathode in an electrolytic cell, attracts cations (positive ions) from the solution.
3. Recognize that the negative electrode must have an excess of electrons to attract these positive ions, since electrons carry a negative charge.
4. Note that the surface of the negative electrode will therefore have an excess of electrons, creating a negative charge at its surface.
5. Conclude that this excess of electrons at the negative electrode surface is what defines its polarity and causes the attraction of cations.