Pieces of zinc react with copper sulfate solution - Edexcel - GCSE Chemistry - Question 8 - 2019 - Paper 1

In this redox reaction, two key changes occur regarding the transfer of electrons:

1. Oxidation: The zinc (Zn) solid loses electrons, which can be represented by the half-equation:

   $ext{Zn(s)} \rightarrow ext{Zn}^{2+}(aq) + 2e^-$

   Here, zinc is oxidised as it loses two electrons, facilitating the reaction.

2. Reduction: The copper (Cu) ions in the copper sulfate solution gain the electrons lost by zinc, as shown in the half-equation:

   $ext{Cu}^{2+}(aq) + 2e^- \rightarrow ext{Cu(s)}$

   Thus, copper ions are reduced as they gain electrons, resulting in the formation of solid copper.