Question

A high nitrogen fertilizer is made by reacting ammonia gas with nitric acid to produce aqueous ammonium nitrate. Can the law of combining volumes be used to predict the volume of ammonia gas required to react with 100 l of nitric acid?

Answer 1

It could, PROVIDED that we know the concentrations of nitric acid, and aqueous ammonia.

Explanation:

Now the reaction is easy to conceive and represent...

`HNO_3(aq) + NH_3(aq) rarr NH_4^+NO_3^(-)(aq)`

Nitric acid is commonly used in the laboratory as a `68%` `"(w/w)"` solution, for which `rho_"density"=1.42*g*mL^-1`..

And thus … `[HNO_3]=((1.42*gxx68%)/(63.01*g*mol^-1))/(1*mLxx10^-3*mL^-1)=15.3*mol*L^-1`...

And so in the given scenario, we gots…

`n_(HNO_3)=15.3*mol*L^-1xx100*L=1532.5*mol`...clearly we need an equiv quantity of ammonia...the which could be worked out by the Ideal Gas equation. More likely, we would add conc. ammonia...for which `rho=0.88 *g*cm^-3`, and which is `35 % *"w/w"`

`[NH_3]=((0.88*g*cm^-3xx35%)/(17.03*g*mol^-1))/(1*mLxx10^-3*mL^-1)=18.1*mol*L^-1`...

With these data...`n_(HNO_3)=100*Lxx15.3*mol*L^-1=1530*mol`..

..the which requires `(1530*mol)/(18.1*mol*L^-1)=84.5*L` conc. ammonia for equivalence.

I acknowledge I answered the question I wanted to answer rather than the question you asked, but the given question was short on qualifying data, the which I had to supply....