The Fertilizers

Total Questions: 21

1. Assertion (A): Chemical fertilizers are necessary for the phosphorus needs of plants. [U.P. Lower Sub. (Mains) 1998]

Reason (R): One metric ton of organic manure can barely supply 2 or 3 kg of phosphorus.

From the above statement, which is correct:

(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

Correct Answer: (a) Both (A) and (R) are true and (R) is the correct explanation of (A).

Solution:Fertilizer is a substance added to soil to improve plant growth and yield. Nitrogen, phosphorus, and potassium (N, P, K) are necessary elements of plants. Only 1.5 to 3 kg of phosphorus is obtained from 1 metric ton of organic manure. Thus, chemical fertilizers are necessary for the phosphorus needs of plants.

2. For wheat cultivation, which fertilizer is used? [47th B.P.S.C. (Pre) 2005]

(a) Nitrogen
(b) Potassium
(c) Copper
(d) Iron

Correct Answer: (a) Nitrogen

Solution:Nitrogen is an essential element of plants. For wheat cultivation, nitrogen fertilizer is most important for its growth and development. Deficiency of nitrogen is the most common nutritional problem affecting the plants.

3. The element not provided by the fertilizers is: [U.P.P.C.S. (Mains) 2007]

(a) Nitrogen
(b) Hydrogen
(c) Chlorine
(d) Phosphorus

Correct Answer: (b) Hydrogen

Solution:Fertilizer is a chemical or natural substance added to soil to increase fertility. There are at least 16 elements essential for the growth of plants. Carbon, hydrogen, and oxygen are derived from carbon dioxide and water. The other elements (N, P, K, etc.) come from the soil in the form of inorganic salts.

4. Which one of the following is not correctly matched?

(a) Nitrogen - Growth and development
(b) Phosphorus - Root development
(c) Potassium - Regulating stomatal opening and closing
(d) Boron - Disease resistance

Correct Answer: (a) Nitrogen - Growth and development

Solution:Nitrogen, phosphorus, and potassium are macro-elements for plants. Boron is a micro-element. Deficiency of nitrogen causes yellowing of leaves and stunted growth, phosphorus helps in root development, potassium regulates stomatal opening and closing, and boron aids in disease resistance.

5. Which one of the following fertilizers leaves maximum acidity in the soil? [U.P.P.C.S. (Pre) 1996]

(a) Urea
(b) Ammonium Sulphate
(c) Ammonium Nitrate
(d) Calcium Ammonium Nitrate

Correct Answer: (b) Ammonium Sulphate

Solution:The soil acidity causes a reduction in the yields of acid-sensitive crops. The acidic soils are readily identified by a soil test showing a low pH value. The soil reaction is alkaline when the pH value is above 7, neutral at 7, and acidic below 7. The extensive use of ammonium sulphate is not recommended on acidic soils because of its greater acidifying properties compared to other nitrogen fertilizers.

6. Urea is: [U.P.P.C.S. (Pre) 2017]

(a) A nitrogen-containing organic compound
(b) A nitrogen-containing inorganic compound
(c) A plant hormone
(d) An Endergonic compound

Correct Answer: (a) A nitrogen-containing organic compound

Solution:Urea is an organic compound whose chemical formula is CO(NH₂)₂. Nearly 46.7% of nitrogen in urea is present in the form of amide. In the field of organic chemicals, it is also called carbamide.

7. The percentage of nitrogen in urea is: [U.P. Lower Sub. (Pre) 2009]

(a) 30%
(b) 25%
(c) 47%
(d) 60%

Correct Answer: (c) 47%

Solution:Urea or carbamide is an organic compound with a chemical formula CO(NH₂)₂, having approximately 46-47% nitrogen. The urea molecule contains two amide (NH₂) groups with nitrogen.

8. The elements present in urea are: [66th B.P.S.C. (Pre) 2020]

(a) C, H, O
(b) C, N, O
(c) C, H, N
(d) C, H, N, O
(e) None of the above / More than one of the above

Correct Answer: (d) C, H, N, O

Solution:Urea or carbamide is an organic compound with a chemical formula CO(NH₂)₂, having approximately 46-47% nitrogen. The urea molecule contains two amide (NH₂) groups with nitrogen.

9. Which form of nitrogen is available in urea? [U.P.P.C.S. (Spl.) (Mains) 2008]

(a) Amide
(b) Ammoniacal
(c) Nitrate
(d) Nitrite

Correct Answer: (a) Amide

Solution:Urea or carbamide is an organic compound with a chemical formula CO(NH₂)₂, having approximately 46-47% nitrogen. The urea molecule contains two amide (NH₂) groups with nitrogen.

10. Which of the following chemical fertilizers is relatively more soluble in water at 20°C? [U.P. P.C.S. (Mains) 2017]

(a) Ammonium Sulphate
(b) Urea
(c) Diammonium phosphate
(d) Ammonium Chloride

Correct Answer: (b) Urea

Solution:Urea is an organic compound that is only stable in an acidic environment. It is named after the Greek word "Oura," meaning urine. Urea is very easily soluble in water compared to other fertilizers.

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The Fertilizers

1. Assertion (A): Chemical fertilizers are necessary for the phosphorus needs of plants. [U.P. Lower Sub. (Mains) 1998]

2. For wheat cultivation, which fertilizer is used? [47th B.P.S.C. (Pre) 2005]

3. The element not provided by the fertilizers is: [U.P.P.C.S. (Mains) 2007]

4. Which one of the following is not correctly matched?

5. Which one of the following fertilizers leaves maximum acidity in the soil? [U.P.P.C.S. (Pre) 1996]

6. Urea is: [U.P.P.C.S. (Pre) 2017]

7. The percentage of nitrogen in urea is: [U.P. Lower Sub. (Pre) 2009]

8. The elements present in urea are: [66th B.P.S.C. (Pre) 2020]

9. Which form of nitrogen is available in urea? [U.P.P.C.S. (Spl.) (Mains) 2008]

10. Which of the following chemical fertilizers is relatively more soluble in water at 20°C? [U.P. P.C.S. (Mains) 2017]

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