Given that M is the mass of a substance deposited during electrolysis and Q is the quantity of electricity consumed, then Faraday's first law can be written as [Electrochemical equivalent]

Step 1. Recall Faraday’s first law of electrolysis:
The mass of a substance deposited (\(M\)) during electrolysis is directly proportional to the quantity of electricity (\(Q\)) passed through the electrolyte.

\( M \propto Q \)

Step 2. Introduce the constant of proportionality:
\( M = EQ \)

Here, \(E\) is the electrochemical equivalent (ECE) of the substance. It depends on the substance’s molar mass and valency, and has units of mass per unit charge (g C\(^{-1}\)).

Step 3. Match with the options:

• A. \(M = \dfrac{E}{Q}\) → incorrect (inverse relation, not correct).
• B. \(M = EQ\) → correct, matches Faraday’s first law.
• C. \(M = \dfrac{Q}{E}\) → incorrect.
• D. \(M = \dfrac{E}{2Q}\) → incorrect.