Electrochemical Cell & EMF of a cell 😊

a. What is electrochemical cell ?

b.Discuss the working and construction of electrochemical cell ?

c. Define EMF of a cell ?

a. Electrochemical cell :-

▪️A chemical cell converts chemical energy into electrical energy, called an electrochemical cell.
▪️When electricity produced, as a result, indirect redox reaction talesplace.
▪️In these cells, an overall or not chemical reaction due to different chemical reactions takes place.
▪️These cell may be classified into 2 types. as, 
1. Reversible cell
2. Irreversible cell
▪️As example, Deniel cell, dry cell, Galvanic cell or the storage batteries can be taken.

b. Construction & Working :-

Construction :-

Apparatus :-

      Two beaker, Cu & Zn rode, Cu-conducting wire, Galvanometer, Salt bridge
▪️ Cell consists of zinc rode dipped with ZnSo₄ Solⁿ & a cupper rod dipped in CuSo₄ Solⁿ. These two solutions are connected by a electrical circuit and a salt bridge as shown. Two electrodes are connected by an electrical circuit and a salt bridge as shown. Two electrodes are connected to Galvanometer by conducting cupper wire. The salt bridge contains electrolyte K₂So₄ or Kcl.

Working :-

▪️ When circuit is complete there is chemical reaction takes place at anode and cathode.
▪️ Oxidation occure at anode and reduction at cathode.
An anode :-

Zn → Zn²⁺ + 2e (Oxdⁿ)

   Electron moves from anode to cathode by the outer conducting wire.

At Cathode :-

Cu²⁺ + 2e →Cu (Redⁿ)

    Electron moves from anode to cathode, that electricity is produced.

Now, the cell is represented as,

Zn/Zn²⁺ |K₂So₄| Cu²⁺/Cu

"Or"

Zn/Zn²⁺ || Cu²⁺/Cu

Function of salt bridge :-

       A glass tube made of agar gel. It plays an important role in electrochemical cell as ;
▪️ It maintains the electrical neutrality of solutions in each of the half cell.
▪️ It also completes the circuit.

c. Electromotive force (EMF) of a cell :-

▪️ It is the potential difference of a cell.
▪️ It is measured by the unit volts (V).
EMF = Redⁿ potential at cathode - Redⁿ potential at anode
Ecell = E_cathode - E_anode

😊 All The Best 😊