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Question

What is the shorthand notation for a galvanic cell that represents the following galvanic cell reaction? 2I-(aq) + Br2(l) = I2(s) + 2Br-(aq)

Answer 1

First, identify what is being reduced (cathode) and what is being oxidized (anode)

I- goes from -1 to zero. It has been oxidized and so is the anode

Br₂ goes from zero to -1. It has been reduced

Now that we know what is oxidized and reduced we can write the standard shorthand notation, in which we always put the cathode on the RIGHT and the anode on the LEFT, separated by a salt bridge.

Since we have species that don't conduct well, we will insert platinum (Pt) as an inert electrode. We then can write the shorthand notation for this cell as:

Pt(s) / I^-(aq) / I₂(s) // Br₂(l) / Br^-(aq) / Pt(s)