Question

How many minutes will it take to plate out 4.50 g of Cu from a solution of Cu(NO3)2 (aq) onto the cathode of an electrolytic cell when 8.00 A of current are used?

a. 28.5 min.b. 3.06 × 10^−9 min.c. 14.2 min.d. 1.82 × 10^3 min.

Answer 1

a. 28.5 min

Step-by-step explanation:

The computation of the number of minutes would it take to plate out is as follows:

Cu+2 +2e
`\rightarrow`Cu

The two moles of electrons could be generated for the copper i.e. deposited

Now

moles of copper is

= 4.5 ÷ 63.5

= 0.071

The 63.5 represents the atomic copper weight

Now mole of electrons deposited is

= 0.071 × 2

= 0.142

Now

quantitiy of electricity needed

= moles of electrons deposited × 96500

= 0.142 × 96500

= 13703 coulums

As per electricity quantity needed

= current × time(seconds)

= 13703 = 8 × t

t = 13703 ÷ 8

= 1713 seconds

= 1713 ÷ 60 minutes

=28.5 min

hence, the correct option is a.