Question

What type of chemical reaction takes place w hen zinc metal is added to a solution of copper(II) sulfate? Which of the compounds or ions used in this lab is toxic? What is a catalyst? Why is universal indicator used in this lab?

Answer 1

1. Zinc metal is a better reducing agent than copper. So when we add zinc metal to Copper sulfate solution, we get zinc sufate and elemental copper in solution.

$Zn(s) + CuSO_{4}(aq.) \rightarrow ZnSO_{4}(aq.) + Cu(s)$

Zinc gets oxidised to zinc sufate because it is a very strong reducing agent. It reduces Copper sulfate to solid copper by taking up the sulfate ion.

3. Catalyst is any substance that enhances the rate of a chemical reaction. It reduces the activation energy of the reaction consequently speeding it up. There are various mechanisms by which the catalysts functions. It operates as a mediator between the reactant molecules so that they collide more frequently which otherwise would have been less probable. Examples of catalysts would be Raney Nickel, Iron pellets, Carbon, potassium permanganate, hydrogen peroxide.