The Daniel Cell – An example of galvanic cells

Question 1

What is the basic principle of the Daniel cell?

Answer 1

Since electrons spontaneously move from Zn to Cu2+ ions, if we separate these two species with a low resistance wire, we can force the electrons to travel
through the connecting wire, and in so doing, create a current flow.

Question 2

In all galvanic cells, electrons will always travel from the ___ 1⁄2 cell to the ___ 1⁄2 cell.

Answer 2

anode

cathode

Question 3

A salt bridge is usually an inverted U-tube, plugged with cotton wool, containing an inert electrolyte, such as ____ or as in the diagram, _____.

Answer 3

KNO3

Na2SO4

Question 4

As the Zn is oxidised, more and more Zn2+ is produced. What happens next according to LCP?

Answer 4

o According to LCP, the equilibrium point will shift to reduce the Zn2+ concentration and therefore the reduction of Zn2+ would begin to occur instead of
further oxidation of Zn.
o Eventually, a point will be reached where the rate of oxidation of Zn is equal to the rate of reduction of Zn2+.
o This means that no electrons will be transferred to the Cu 1⁄2 cell and the cell will stop functioning.
o Once the half cells reach equilibrium, the potential difference between the cells would be zero.

Question 5

Are Daniel cells examples of direct or indirect cell transfer?

Answer 5

Indirect

Question 6

Why is KNO3 the most preferred salt bridge?

Answer 6

As there is less chance of precipitate.

Question 7

In galvanic cells, anode is ___ and cathode is ____.

Answer 7

negative

positive

Question 8

Anode would be more positive due to excess ____.

Answer 8

cations

Question 9

Cathode would be more negative due to excess ____.

Answer 9

anions