Question

What is the mass of sulfate of ammonia that can be obtained from 1.00 tonne of sulfuric acid and 0.500 tonne of ammonia?

Answer 1

Well, we need (i) a stoichiometric equation..............and get `B`.

Explanation:

`2NH_3 + H_2SO_4 rarr (NH_4)_2SO_4`.

Two equiv of ammonia react with one equiv sulfuric acid to give one equiv of the salt, `"ammonium sulfate"`. This is an acid-base reaction.........

And so we calculate the molar equivalence of each of the given reagents.......(ii)

`"Moles of sulfuric acid"=(1000xx10^3*g)/(98.08*g*mol^-1)=10.2xx10^3*mol.`

`"Moles of ammonia"=(500xx10^3*g)/(17.03*g*mol^-1)=29.4xx10^3*mol.`

Now clearly, there is a STOICHIOMETRIC excess of ammonia. Agreed? And the limiting reagent is sulfuric acid. At equivalence, there are `10.2xx10^3*mol` of ammonium sulfate.........

This represents a mass of `10.2xx10^3*molxx132.14*g*mol^-1`

`=1348*kg`, i.e. `1.35*"tonne"`, and so you know which option.......

Now this is a hard question for an A-level student, or even a 1st year chem student. But all I have done is to (i) write the stoichiometric equation, and (ii) calculated the molar equivalence; and this is made difficult here because they quote mass in `"TONNES"` rather than the more familiar `"grams"` (and this is why I converted the mass to grams initially - chemists typically work in gram quantities). I agree that this is a lot of work for a multiple choice question.

As to the second part of your question, ammonia, is a BASIC species. It undergoes an acid base reaction in water according to the following reaction.........

`NH_3+H_2OrightleftharpoonsNH_4^(+) + HO^-`;

were I do to this with hydrochloric acid, I would get:

`NH_3(aq) + HCl(aq) rarr NH_4Cl(aq)`

SOME POINTS TO CONSIDER............

`"Ammonium chloride"` or `"ammonium sulfate"` ARE SALTS............

`"Ammonia"` is a colourless gas, `NH_3(g)`, with a foul, penetrating odour. We can make aqueous solution of ammonia (ammonia gas has substantial water solubility), but the dominant species in solution is the free-base, `NH_3`, and there only small equilibrium quantities of ammonium ion. This is knowledge that I would expect of a 1st year university student, or of a good A level student.