Question

How many seconds would it take to deposit 17.3 g of Ag (atomic mass = 107.87) from a solution of AgNO3 using a current of 10.00 amp? a) 3.09 x 103 s b) 7.74 x 102 s c) 4.64 x 103 s d) 1.55 x 103 s e) 5.16 x 102 s

Answer 1

Mass of Ag = 17.3 gm

Moles of Ag = 17.3 g / 107.86 g/mol = 0.16039 Moles

Let us write half-reaction at cathode

Ag⁺ + e^- ====> Ag(s)

number of moles of electrons required = 0.16039 Mole e -  

Let us calcualte moles of electrons to coulombs of charge with Faraday's constant.

0.16039 Mole e - x 96485 = 15.475.528 coulombs

Hence 15.475.528   coulombs of charge is required

Let us calculate the time using  coulombs of charge and current

10 A x t =  15.475.528

t = 15475 Seconds or 1.55 x 10³ seconds

Hence Option D is correct answer