Question

HNO3 oxidises NH4 ions to Nitrogen and itself gets reduced to NO2.the mole of HNO3 required by 1 mole of (NH4)2SO4 is

Answer 1

We need 3 equiv of nitric acid per equiv of ammonia/ammonium.

Explanation:

Reduction half equation:

HNO3(aq)+H++e−→NO2(g)+H2O(l)
+VN→+IVN

Oxidation half equation:

NH+4→12N2(g)↑⏐ ⏐⏐+3e−+4H+
−IIIN→0N

3HNO3(aq)+NH+4→3NO2(g)+3H2O(l)+12N2(g)↑⏐ ⏐⏐+H+

And we can make it a bit simpler than this....by representing the oxidation of ammonia rather than ammonium.....and so we remove H+ from each side of the equation.....

3HNO3(aq)+NH3(aq)→3NO2(g)+12N2(g)↑⏐ ⏐⏐+3H2O(l)

The which is balanced with respect to mass and charge, as indeed it must be if we purport to represent chemical reality.