Question

The nitrogen fertilizer with highest percentage of nitrogen is:
[A] Urea
[B] Ammonium Sulphate
[C] Ammonium nitrate
[D] Calcium nitrate

Answer 1

HINT: Nitrogen based fertilizers are needed for rapid growth of plants. It also supports healthy growth. The fertilizer with the highest nitrogen content contains around 46% nitrogen thus it is not applied pure but mixed with other agents.

COMPLETE STEP BY STEP SOLUTION: We know that a fertiliser is synthetic or a natural material mixed with the soil to give the plants growing in that soil the nutrients that it needs while growing. These fertilisers are of various kinds depending upon their base of origin i.e. natural or synthetic and the compounds used for making it. The most common fertilizers are nitrogenous bases but there are others too like phosphates and potassium based. Now let us discuss the fertilizers given to us and find out the one with the highest percentage of nitrogen. Firstly, we have Urea. We also know it by the name carbamide and it is an organic compound with the formula $CO{{\left( N{{H}_{2}} \right)}_{2}}$. It is the most commonly used nitrogenous fertilizer due to its high nitrogen content. It contains around 46% nitrogen. Then we have ammonium sulphate. It is an inorganic salt with the formula ${{\left( N{{H}_{4}} \right)}_{2}}S{{O}_{4}}$. It has various commercial uses but most commonly it is used as a soil fertilizer. It consists of 21% nitrogen and 24% sulphur.
Next we have ammonium nitrate. It is a chemical compound with formula $N{{H}_{4}}N{{O}_{3}}$. It is also a nitrogenous fertilizer but it is not as strong in nitrogen content as urea. It contains around 34% nitrogen. And lastly we have calcium nitrate. It is an organic compound with the formula $Ca{{\left( N{{O}_{3}} \right)}_{2}}$. It contains around 15.5% nitrogen and 26.5% calcium. Most of its nitrogen content is from the nitrate part.
We can see from the above discussion that urea has the highest nitrogen content.

Therefore, the correct answer is option [A] Urea.

NOTE: Nitrogen based fertilizers are very commonly used but only a fraction of these fertilizers is converted into plant matter. The remaining is accumulated in the soil. There are many adverse effects of nitrogen and phosphorus based fertilizers on the environment. Due to heavy rainfall, these fertilizers are washed away into waterways and cause eutrophication of freshwater bodies. These run-offs are the primary cause of depletion of oxygen in parts of the ocean.