Question

All the substances listed below are fertilizers that contribute
nitrogen to the soil. Which of these is the richest source of
nitrogen on a mass percentage basis?

(a) Urea, (NH2)2 CO
(b) Ammonium nitrate, NH4 NO3,
(C) Nitric oxide, NO
(d) Ammonia, NH3​

Answer 1

Ammonia is richest source of nitrogen on a mass % basis.

Answer 2

Compound

Urea (NH2)2CO(NH2)2CO 28×100/60=46.67%

Ammonia NH3NH3 14×100/17=82.35%

Ammonium nitrate NH4NO3NH4NO3 28×100/80=35%

Nitro oxide NO

14× 100/ 30 = 47%

Hence, ammonia is the richest source of nitrogen on a mass percentage basis.

Hope it's helpful