Question

calculate the current (in mA) required to deposit 0.195 g of platinum metal in 5.0 hours from a solution of [PtCl6]2- : (atomic weight : Pt = 195)

solution please​

Answer 1

Answer : The current (in mA) required is, 21.44 mA

Explanation :

Using Faraday' First Law of electrolysis,

$w=\frac{I\times t\times M}{F\times z}$

where,

w = Mass of substance deposit = 0.195 g

I = current = ?

t = time = 5 hours = $(5\times 60\times 60)s$

M = molar mass of metal = 195 g/mole

F = Faraday = 96500 C

z = valency of the metal = 4

Now put all the given values in the above formula, we get the current required.

$0.195g=\frac{I\times (5\times 60\times 60)s\times 195g/mole}{96500C\times 4}$

$I=0.02144A=21.44mA$       (conversion : 1 A = 1000 mA)

Therefore, the current (in mA) required is, 21.44 mA