KCET2017Chemistryp Block Elements (Group 13 & 14)
In the electrolysis of aqueous sodium chloride solution, which of the half cell reaction will occur at anode?
Options
- A( N a⁺(a q)+e⁻ N a(s) ; E_ cell ^ =-2.71 ) volts
- B( 2 H ₂ O ( l ) O ₂+4 H ⁺+4 e⁻ ; E _ cell ^ =1.23 ) volts
- C( H⁺(a q)+e⁻ 1 2 H₂ ; E_ cell ^ =0.00 ) volts
- D( Cl ⁻(a q) 1 2 Cl ₂+e⁻ ; E_ cell ^ =1.36 ) volts
Correct answer
D. ( Cl ⁻(a q) 1 2 Cl ₂+e⁻ ; E_ cell ^ =1.36 ) volts
Step-by-step solution
In water sodium chloride ionizes as ( N a C l(a q) N a⁺(a q)+C l⁻(a q) ) water also dissociates into ions, though to very slight degree as, ( H ₂ O ( l ) H ⁺(a q)+ OH ⁻(a q) ) Thus, the aqueous solution of sodium chloride contains ( N a⁺, H ⁺, OH ⁻ )and ( Cl ⁻ )ions. When electric current is passed through the solution, ( Cl ₂ ) gas evolved at anode and hydrogen is evolved at the cathode. The resulting solution contains ( Na ⁺ )and ( OH ⁻ )ions. Oxidation of ( Cl ⁻ )ions and ( H ₂ O ) is possible at anode but, stan