Question

4.
How long will a current of 5 amperes be passed through aqueous
solution of cadmium sulphate to coat a metal plate of 150 cm2 area
with a 0.002 mm thick layer. Density of cadmium is 8.64 g cm
Atomic mass of cadmium = 112.5 amu. (1 minute 30 seconds)
3​

Answer 1

Answer:

Explanation:

Area X thickness = 150 cm^2 x 0.002 mm

                             = 0.3 cm^3           ( 1mm = 0.1 cm )

Density of cadmium = 8.64 g/cm^3

mass of cadmium to be deposited = Density X volume

                                     = 8.64 x 0.3 = 2.592 g

112.5 of cadmium is deposited by =96500 coloumb of electricity

2.592 of cadmium is deposited by $\frac{96500}{112.5}$ x 2.59 = 2223.4 of electricity

  Q = i x t

i = current in amperes = 5 A

t = time in seconds

2223.4 C = 5 A x t

= 444.67 sec