The **SI unit of electrochemical equivalent** is **kilogram per coulomb (kg/C)**.
### Explanation:
The electrochemical equivalent (Z) represents the mass of a substance deposited or dissolved during electrolysis when one coulomb of electric charge passes through the electrolyte. It is defined as:
\[
Z = \frac{\text{Mass deposited (m)}}{\text{Charge passed (Q)}}
\]
- **Mass (m)** is measured in kilograms (kg) in the SI system.
- **Charge (Q)** is measured in coulombs (C) in the SI system.
Thus, the electrochemical equivalent has units of **kg/C**, meaning the mass of the material deposited per unit of charge.
### Context:
The electrochemical equivalent is closely related to **Faraday's laws of electrolysis**, which describe how the amount of a substance produced at an electrode is proportional to the electric charge passed through the electrolyte.