C5. Electricity and chemistry

Question 1

positive elctrode

Answer 1

anode

Question 2

negative elctrode

Answer 2

cathode

Question 3

anode

Answer 3

positive elctrode

Question 4

define electrolysis

Answer 4

breaking down of ionic compound
when molten/in an aqueous solution
by the passage of electricity current

Question 5

when a molten ionic compound is electrolysed, what happens to the
anode
cathode

Answer 5

anode: non-metal
cathode: metal forms

Question 6

when AQUEOUS sodium chloride is electrolysed, what happens to the ANODE

Answer 6

anode : chlorine gas ions lose electrons and are discharged as chlorine gas
2CL-(ap) → CL2(g) + 2e-

Question 7

when AQUEOUS sodium chloride is electrolysed, what happens to the CATHODE

Answer 7

cathode: hydrogen ions accept electrons and hydrogen gas is discharged
2H+(ap) + 2e- → H2(g)

Question 8

what is discharged

Answer 8

changed into an atom or molecule at the electrode

Question 9

why is hydrogen is discharged rather than sodium in a concentrated AQUEOUS solution of sodium chloride

Answer 9

hydrogen is lower in the discharge series/ less reactive

Question 10

what happens to the electrodes when copper chloride is electrolysed

Answer 10

anode: chlorine gas
cathode: copper