Identify the method of ore purification and the reducing agent in the provided copper extraction reaction.

e) The methods used to purify the ore (concentrate the ore) are:

• Froth flotation

I. The reducing agent in the given equation is:

$$\text{Cu}_2\text{S} + 2\text{Cu}_2\text{O} \text{(s)} \longrightarrow 6\text{Cu} \text{(s)} + \text{SO}_2 \text{(g)}$$

In this reaction, sulfur in $\text{Cu}_2\text{S}$ is oxidized from -2 to +4 in $\text{SO}_2$. Therefore, $\text{Cu}_2\text{S}$ acts as the reducing agent.
The reducing agent is $\boxed{\text{Cu}_2\text{S}}$.

II. This type of copper is called "blister copper" because during the solidification of molten copper, sulfur dioxide gas ($\text{SO}_2$) escapes, creating blisters or bubbles on the surface of the copper.