Answer to Question #171319 in General Chemistry for mike

Question

Nickel (II) sulfate is green. A solution of this salt is electrolysed using nickel electrodes.

a)  Write a half-equation for the reaction at each electrode.      

b) At which electrode does reduction take place?

c) What happens to the size of the anode?

d) The colour of the solution does not change during electrolysis. Explain why.

e) Suggest one industrial application for this process.

Answer 1

A) Ni→Ni+2+2e−During electrolysis of nickel sulphate using nickel electrode, at anode, oxidation of nickel occurs. Nickel loses two electrons to form Ni2+ ion.

B) Reduction happens at the negative cathode because this is where positive ions gain electrons. Oxidation happens at the positive anode because this is where negative ions lose electrons.

C) The anode is a reducing agent because its behaviour will reduce ions at the cathode. Mass decreases as the reacting anode material becomes aqueous. These ions are the oxidizing agent because by taking electrons, they cause the anode to be oxidized. Mass increases as aqueous ions turn to solid at the cathode.

D) During the electrolysis of copper sulfate solution it splits into copper ions and sulfate ions. If copper electrodes are dipped copper ions move to cathode while sulfate ion move to anode and become a radical so it attacks copper cathode and forms copper sulfate in solution itself.

E) Nickel Sulfate is a green to yellow crystalline (sand-like), odorless solid. It is used to make other Nickel compounds, as a mordant in dyeing and printing textiles, and in coatings and ceramics.