Answer to Question #170351 in Organic Chemistry for mark

Question

For the reaction:

Zn + Cu(NO3)2 → Zn(NO3)2 + Cu

Explain, in terms of electrons, why it is a redox reaction. You must use half equations in

your answer.

Answer 1

When the zinc atoms lose electrons the zinc ions go into solution and the 2 electrons flow away from this electrode into the external circuit.

When they arrive at the copper electrode, they are picked up by the copper(II) ions to become copper atoms.

The two half cells are connected by a salt bridge or a membrane. The salt bridge consists of some filter paper soaked in a suitable electrolyte such as saturated potassium nitrate solution.

The two half cell equations are ;

$Zn_{(aq)} \to$ $Zn_{(aq)} ^{2 +} +2e$

$Cu_{(aq)} ^{2 +} +2e\to Cu_{(s)}$