What is the composition of nitrolim, a chemical fertilizer?

Which of the following statements are true about urea?

I. Urea is the first organic compound which is synthesised in the laboratory.

II. Urea is the best water-soluble nitrogenous fertilizer.

III. Urea leaves only ${\mathrm{CO}}_2$ after ammonia has been assimilated by plants.

Which of the following are nitrogen fertilizers?

I. Calcium cyanamide.

II. Urea

III. Bone ash.

IV. Ammonium sulphate.

Select the correct answer using the codes given below.

Consider the following statements relevant to fertilizers.

I. Superphosphate of lime contains $\mathrm{Ca}{\left({\mathrm{H}}_2{\mathrm{PO}}_4\right)}_2$ and ${\mathrm{CaSO}}_4$.

II. Triple superphosphate is obtained by treating calcium phosphate with concentrated ${\mathrm{H}}_2{\mathrm{SO}}_4$ acid.

III. Chief potash manures are $\mathrm{KCl}, {\mathrm{K}}_2{\mathrm{SO}}_4$ and ${\mathrm{KNO}}_3$.

IV. The chemical manures must be soluble in soil moisture.

Which of the above statements are correct?