(a) What is a galvanic cell? (b) Name the cathode and anode used in the Daniell cell. (c) Name the cell represented by Pt(S), H2(g)/H+(aq).

Question

We can construct innumerable number of galvanic cells on the pattern of Daniell cell by taking combi nation of different half cells.

(a) What is a galvanic cell?

(b) Name the cathode and anode used in the Daniell cell.

(c) Name the cell represented by Pt_(S), H_2(g)/H⁺_(aq).

(d) According to convention what is the potential of the above cell at all temperatures?

(e) Write the use of the above cell.

Answer 1

(a) It is a device for converting chemical energy into electrical energy. The decrease in free energy in a spontaneous chemical process appears as elec trical energy. e.g., Daniell cell,

(b) A zinc rod dipped in 1 M solution of ZnSO₄ acts as the anode. Here oxidation takes place. A copper rod dipped in 1 M solution of CuSO₄ acts as the cathode. Here reduction takes place.(c) This represents the andard Hydrogen Electrode (S.H.E), when it acts as the anode.

(d) According to convention, S.H.E is assigned a zero potential at all temperatures

(e) It is used as a primary reference electrode for determining the standard electrode potential of an unknown electrode. The electrode whose standard potential is to be determined is coupled with a reference electrode of known potential i.e., S.H.E to get a galvanic cell. The potential of the resulting galvanic cell is determined experimentally. E = E – E Knowing the potential of one electrode that of the other can be calculated.