Question

The quantity of charge required to obtain one mole of aluminium from Al2O3 is ___________.
(i) 1F
(ii) 6F
(iii) 3F
(iv) 2F


NCERT Class XII
Chemistry - Exemplar Problems

Chapter 3. Electrochemistry

Answer 1

Charge on Al in Al2O3
2Al +3O =0
OXYGEN HAS -2 CHARGE
SO, 2Al +3(-2)=0
2Al -6=0
2Al=6
Al=3
THEREFORE CHARGE REQUIRED FOR 1MOL OF Al IN Al2O3 =3F
HENCE CORRECT OPTION IS III - 3F

Answer 2

Al₂O₃
=> 2x +3(-2) =0
=>2x = 6
=>x=3

∴ Al=3