# The Usefulness of a Fertilizer Depends Upon Percentage of Nitrogen Present in It. Find Which of the Following is a Better Fertilizer - Chemistry

Short Note

The usefulness of a fertilizer depends upon percentage of nitrogen present in it. Find which of the following is a better fertilizer:
(a) Ammonium nitrate [NH4NO3]
(b) Ammonium phosphate [(NH4)3PO4 (N=14,H=1,O=16,P=31)

#### Solution

(a) Percentage of nitrogen in Ammonium nitrate [NH4NO3]:
(N)2 + (H)4 + (O)3
14 x 2 + 1 x 4 + 3 x 16 = 80.
So, the molecular mass of NH4NO3 = 80.
80 by weight of NH4NO3 contain 28 parts by weight of nitrogen .
100 parts will contain = 28 x 100 /80 = 35‰
So, the percentage composition of nitrogen in Ammonium nitrate is 3535‰
(b) Percentage of nitrogen in Ammonium phosphate [(NH4)3PO4]:
(N)3 + (H)12 +P + (O)4
14 x 3 + 1 x 12+ 31 + 16 x 4 = 149 .
So, the molecular mass of NH4NO3 = 149 .
149 by weight of (NH4)3PO4.contain 42 parts by weight of nitrogen .
100 parts will contain = 42 x 100 /149 = 28.18‰
So, the percentage of nitrogen in ammonium phosphate is 28.18‰
Since the percentage of nitrogen is more in Ammonium nitrate so it is a better fertilizer.

Concept: Relationship Between Vapour Density and Relative Molecular Mass
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#### APPEARS IN

Frank ICSE Class 10 Chemistry Part 2
Chapter 5 Mole Concept And Stoichiometry
Exercise | Q 5 | Page 116