For how long a current of 1.5 ampere has to be passed through the electrolyte innorder to deposit 1g of Al when the electrode reaction is
Al3+ +3e → Al (Z=27)
Current = 1.5 A
Given mass of Al = 1 g
Molar mass of Al =27 g
No. of moles of Al = 1/27 moles
according to the balance chemical equation :
Given mass of Al = 1 g
Molar mass of Al =27 g
No. of moles of Al = 1/27 moles
according to the balance chemical equation :
To produce 1 mole of Al = 3 moles of electrons are required
To produce 1/27 moles of Al = 3 x (1/27) moles of electrons =1/9 moles of electrons
Charge on 1 mole of electrons =96500 C
Charge on 1/9 moles of electrons = 96500/9 C = 10722.22 C
Charge = current x time(sec)
Time = charge / current = 10722.22/ 1.5 = 7148.1481 seconds
Time (minutes) = 119.14 minutes or 2 hours approximately