Question

How many minutes will it take to electroplate 34.1 g of gold by running 5.00 A of current through a solution of Au+(aq)?

Answer 1

Electrolysis equation is:

Au1+ + 1e- ------> Au

1 mol of Au requires 1 mol of electron

1 mol of electron = 96485 C

So,1 mol of Au requires 96485 C

let us calculate mol of element deposited:

use:

number of mol, n = mass/molar mass

= 34.1/1.97*10^2

= 0.1731 mol

total charge = mol of element deposited * charge required for 1 mol

= 0.1731*9.649*10^4

= 1.67*10^4 C

use:

time = Q/i

= 1.67*10^4/5

= 3.34*10^3 seconds

= 3.34*10^3/60 min

= 55.7 min

Answer: 55.7 min