Question

how many mol Fe2 + ions are formed when excess of iron is treated with 50 ml of 4.0 M HCL under inert atmosphere assume no change in volume

Answer 1

The equation for this reaction is as follows:

2HCl + Fe ---> Fe2+ + H2 + 2Cl-

which can also be written as

2H+ + Fe ---> Fe2+ + H2

The Cl- ions do not take place in the reaction itself so they can be removed.

Thus, simple equation would be:

 2HCl + Fe ---> Fe2+ + H2 + Cl-

 Now, Molarity x Volume (in litres)

= moles 4M x (.05L)

= 0.2mol (HCl) 0.2 mol HCL x [1 mol Fe2+ / 2mol HCl]

 = 0.2/2 = 0.1 mol Fe2+ ions