Question

Enter your answer in the provided box. A constant current is passed through an electrolytic cell containing molten MgCl2 for 15.0 h. If 8.70 x 109 g of Cl, are obtained, what is the current in amperes?

please help me!

Answer 1

MgCl₂  $\rightarrow$ Mg⁺² + 2Cl^-

2Cl^-$\rightarrow$ Cl₂ + 2e^- (at anode)

Mg⁺² + 2e^-  $\rightarrow$ Mg (at cathod)

W = (i$\times$t$\times$M.W.)/(F$\times$n)

W= amount of chlorine released in grams (g) = 8.7$\times$10⁵ g

i = current passed in Ampere (Amp) = ?? (need to find)

t = time in Seconds (s) = 15 h i.e. 54000 s

M.W. = molecular weight of Cl2 = 71 g/mol

F =Faraday constant = 96500 sA/mol

n = number of electrons transferred (2 in this case, see above equations)

Substitute all these parameters in above formula

8.7$\times$10⁵ = (i$\times$54000$\times$71)/(96500$\times$2)

8.7$\times$10⁵ = (i$\times$3834000)/(193000)

8.7$\times$10⁵ = (i$\times$3834)/193

8.7$\times$10⁵ = i$\times$19.87

i=8.7$\times$10⁵/19.87

i=0.438$\times$10⁵

i=4.38$\times$10⁴ amp