Question

In 1901, Thomas Edison invented the nickel-iron battery. The following reaction takes place in the battery. Fe(s) + 2 NiO(OH)(s) + 2 H2O(l) Fe(OH)2(s) + 2 Ni(OH)2(aq) How many mole of Fe(OH)2, is produced when 4.20 mol Fe and 6.70 mol NiO(OH) react?

Answer 1

Answer:

3.35 mole.

Explanation:

• It is a stichiometriy oriented problem.

• From the balanced equation: Fe + 2NiO(OH) + 2H₂O → Fe(OH)₂ + 2Ni(OH)₂

• It is clear that 1.0 mole of Fe reacts with 2.0 moles of NiO(OH) to produce 1.0 mole of Fe(OH)₂.

• Fe reacts with NiO(OH) with 1:2 ratio.

• So, 6.70 mole of NiO(OH) will react completely with (6.70 x 0.5 = 3.35 mole) of Fe. But Fe is present in excess (4.20 mole), so the limiting reactant is NiO(OH).

Using cross multiplication and from the stichiometry:

2.0 moles of NiO(OH) produce → 1.0 mole of Fe(OH)₂

6.70 mole of NiO(OH) produce → ??? mole of Fe(OH)₂

∴ The number of moles of Fe(OH)₂ produced = (1.0 mole) *6.70 mole) / (2.0 mole) = 3.35 mole.