Question

A certain metal M forms a soluble sulfate salt M2SO4. Suppose the left half cell of a galvanic cell apparatus is filled with a 50.0mM solution of M2SO4 and the right half cell with a 5.00M solution of the same substance. Electrodes made of M are dipped into both solutions and a voltmeter is connected between them. The temperature of the apparatus is held constant at 20.0°C.
Which electrode will be positive?

Left

Right

Answer 1

Answer:

Right

Explanation:

The given parameters are;

The soluble sulfate formed by the metal, M = M₂SO₄

In the galvanic cell formed by the metal M, we have;

The concentration of M₂SO₄ in the left half cell = 50.0 mM = 0.05 M

The concentration of M₂SO₄ in the right half cell = 5.00 M

In the galvanic cell, the metal 'M' will be dissolved into the solution with lower concentration as M²⁺ which is the left half cell, making the cell negative and the solution more concentrated

In the right half cell, the metal 'M²⁺' in the solution will be plated unto the electrode making the solution less concentrated and the electrode in the right half cell will be the positive electrode

Therefore;

The electrode which will be positive is the electrode in the right half cell.