Question

How can chemical energy be converted into electrical energy?

Answer 1

Galvanic cell:

• A galvanic cell is a type of electrochemical cell that is used to convert chemical energy into electrical energy.
• Electrical energy does not directly convert to chemical energy. Electrolysis is the process by which this interaction can take place.
• In a galvanic cell, the chemical reactions occur in the internal circuit whereas the electrons carry the electrical energy through a wire in the external circuit.
• In the external circuit, we can simply use the generated electric energy, for a light bulb or can use it for any electrical appliance by connecting it through a wire to the circuit.

Working of Galvanic cell:

• A galvanic cell involves a chemical reaction that makes the electric energy available.
• During a redox reaction, a galvanic cell uses the energy transfer between electrons to convert chemical energy into electric energy.
• In a Galvanic cell, the following reaction occurs:

$\mathrm{Zn}\left(\mathrm{s}\right)+{\mathrm{Cu}}^{2+}(\mathrm{aq}.)⟶{\mathrm{Zn}}^{+2}\left(\mathrm{aq}\right)+\mathrm{Cu}\left(\mathrm{s}\right)$

• This flow of electrons which is essentially called a current can be made to flow through a wire to complete a circuit.
• A galvanic cell can be formed of any two metals which can form the anode and the cathode if left in contact with each other.
• A connecting circuit shall be required in which there is a container where a solution of concentrated Copper Sulphate $({\mathrm{CuSO}}_4)$ is kept inside it and a copper rod is inserted inside the solution to act as the cathode.
• Inside which a porous container is kept in which concentrated Sulphuric Acid $({\mathrm{H}}_2{\mathrm{SO}}_4)$ is filled in which a Zinc rod is inserted in it which acts as an anode.
• Thus when a wire is connected through the copper rod and zinc rod in which an electric current starts to flow.
• Reactions of Daniel cell at cathode and anode are:

At cathode: ${\mathrm{Cu}}^{2+}+2{\mathrm{e}}^{–}\to \mathrm{Cu}$

At anode: $\mathrm{Zn}\to {\mathrm{Zn}}^{2+}+2{\mathrm{e}}^{–}$

• The figure showing the working process of a galvanic cell is given by;

Hence, chemical energy is converted into electrical energy by using the Galvanic or Daniell cell.