Question

Three faradays of electricity was passed through an aqueous solution of iron(II) bromide. The mass of iron metal (At. mass $56$) deposited at the cathode is:

• A. $56g$
• B. $84g$
• C. $112g$
• D. $168g$

Answer 1

The correct option is B $84g$

${Fe}^{2+}+2e^{-}\to Fe$

n=2 as 2 electrons are exchanged in this reaction

3F charge is passed which implies 3 moles electrons are passed.

1 mole of Fe is formed when 2 moles of electrons are passed.

For 3 moles of electrons passed 1.5 moles of Fe will be formed.

mass of iron deposited$=56\times 1.5=84g$