<h3>Answer:</h3>
         NH₃ > NH₄NO₃ > (NH₄)₂HPO₄ > (NH₄)₂SO₄ > KNO₃ >  (NH₄)H₂PO₄
<h3>Soution:</h3>
In (NH₄)₂HPO₄:
Mass of Nitrogen  =  N × 2  =  14 × 2  =  28 g.mol⁻¹
Molar Mass of (NH₄)₂HPO₄  =  132.06 g.mol⁻¹
Mass %age  =  Mass of N / M.Mass of (NH₄)₂HPO₄ × 100
Mass %age  =  28 g.mol⁻¹ / 132.06 g.mol⁻¹ × 100
Mass %age  =  21.20 %
In (NH₄)₂SO₄:
Mass of Nitrogen  =  N × 2  =  14 × 2  =  28 g.mol⁻¹
Molar Mass of (NH₄)₂SO₄  =  132.14 g.mol⁻¹
Mass %age  =  Mass of N / M.Mass of (NH₄)₂SO₄ × 100
Mass %age  =  28 g.mol⁻¹ / 132.14 g.mol⁻¹ × 100
Mass %age  =  21.18 %
In KNO₃:
Mass of Nitrogen  =  N × 1  =  14 × 1  =  14 g.mol⁻¹
Molar Mass of KNO₃  =  101.10 g.mol⁻¹
Mass %age  =  Mass of N / M.Mass of KNO₃ × 100
Mass %age  =  14 g.mol⁻¹ / 101.10 g.mol⁻¹ × 100
Mass %age  =  13.84 %
In (NH₄)H₂PO₄:
Mass of Nitrogen  =  N × 1  =  14 × 1  =  14 g.mol⁻¹
Molar Mass of (NH₄)H₂PO₄  =  115.03 g.mol⁻¹
Mass %age  =  Mass of N / M.Mass of (NH₄)H₂PO₄ × 100
Mass %age  =  14 g.mol⁻¹ / 115.03 g.mol⁻¹ × 100
Mass %age  =  12.17 %
In NH₃:
Mass of Nitrogen  =  N × 1  =  14 × 1  =  14 g.mol⁻¹
Molar Mass of NH₃  =  132.14 g.mol⁻¹
Mass %age  =  Mass of N / M.Mass of NH₃ × 100
Mass %age  =  14 g.mol⁻¹ / 17.03 g.mol⁻¹ × 100
Mass %age  =  82.20 %
In NH₄NO₃:
Mass of Nitrogen  =  N × 2  =  14 × 2  =  28 g.mol⁻¹
Molar Mass of NH₄NO₃  =  80.04 g.mol⁻¹
Mass %age  =  Mass of N / M.Mass of NH₄NO₃ × 100
Mass %age  =  28 g.mol⁻¹ / 80.04 g.mol⁻¹ × 100
Mass %age  =  34.98 %