Question

How many moles of NO2 (g) are required to react with 1.50 moles of water to produce 4.00 moles of nitirc acid?

Answer 1

H₂O_(l) + 3NO_2(g) ---------> 2HNO_3(aq) + NO_(g)

Moles of water = 1.5 moles

Moles of nitric acid = 4 moles

Molar ratio of water and nitric acid = 1:2

Molar ratio of nitrogen dioxide and nitric acid = 3:2

With relative water (reactant) :

a) 1 mole of water required to react 2 moles of nitrogen dioxide

1.5 moles of water require ---> 1.5 x 2 = 3 moles of nitrogen dioxide is required to react with 1.5 moles of water

with relative product (nitric acid)

b) 2 moles of nitric acid is formed from 3 moles of nitrogen dioxide

4 moles of nitric acid -----> ? = 4x3/2 = 6 moles of nitrogen dioxide is required to form 4 moles of nitric acid

But there is difference in the moles of nitrogen dioxide i,e 3 moles.

For the formation of 4 moles nitric acid we require 2 moles of water and 6 moles of nitrogen dioxide but only 1.5 moles of water is present. (Molar ratio of water and nitric acid = 1:2)

This shows that there is no enough water to produce 4 moles of nitric acid because it is limiting reactant when compared with nitrogen dioxide