# Why copper sulphate is a catalyst in this reaction

Recently, we learnt about catalyst is a substance can increase the rate of reaction without any without itself undergoing any permanent chemical change.The experiment we did was the reaction between zinc and hydrochloric acid as the equation below

$$\ce{Zn + 2HCl -> ZnCl_2 + H_2}$$

However the thing I don't understand is why copper sulphate is a catalyst when the copper ion is reduced to copper atom as the equation below

$$\ce{Cu^2+ + Zn -> Cu + Zn^2+}$$

I mean how could it call as a catalyst when it is reduced from ion to atom

• Where in the reaction is copper sulphate used? You just mentioned it as catalyst. The reaction you mentioned doesn't actually need to be catalyzed to occur at a reasonable rate – Tamoghna Chowdhury Jan 16 '16 at 12:46
• Anyway, in the particular ionic equation you provided copper sulphate could not in fact be called a catalyst, but maybe in some other step following this in the whole reaction copper sulphate is regenerated from copper metal – Tamoghna Chowdhury Jan 16 '16 at 12:51
• Is it the hydrochloric acid? – Simon-Nail-It Jan 16 '16 at 16:46
• The hydrochloric acid is a reagent here. It's not a catalyst. – Tamoghna Chowdhury Jan 16 '16 at 17:09
• So your sulphate ion have to do something with copper atom after reduced – Simon-Nail-It Jan 16 '16 at 23:11

## 1 Answer

The reaction rate increases because the copper is deposited on particles of zinc, creating a galvanic couple causing galvanic (aka electrolytic) corrosion. [It could be argued that this is not catalysis, because the copper sulfate is entering into a reaction.]