Q24. In which of the following industry is rock-phosphate utilized?
[MPPSC Assistant Professor GS Paper II, 2022 cycle (17 November 2024)]
(A) Cement Industry
(B) Iron-steel Industry
(C) Fertilizer Industry
(D) Cotton textile Industry
Answer: (C) Fertilizer Industry
Explanation: Phosphate rock is the principal mineral feedstock for manufacturing phosphatic fertilisers. Treatment with acids converts comparatively insoluble mineral phosphates into forms suitable for crops. Important products include single superphosphate and phosphoric acid-derived fertilisers such as diammonium phosphate.
Q23. Consider the following fertilizers:
(a) Urea,
(b) Ammonium nitrate,
(c) Triple superphosphate,
(d) Potassium sulphate.
Which of the above are nitrogenous fertilizers?
[KEA Village Administrative Officer GK Paper I (27 October 2024)]
(A) (a) and (c) only
(B) (a), (b) and (c) only
(C) (a) and (b) only
(D) (b), (c) and (d) only
Answer: (C) (a) and (b) only
Explanation: Urea and ammonium nitrate both contain nitrogen and are classified as nitrogenous fertilisers. Triple superphosphate chiefly supplies phosphorus, while potassium sulphate supplies potassium and sulphur. Fertilisers are commonly classified as nitrogenous, phosphatic or potassic according to their principal nutrient.
Q22. Which inorganic compound is known to undergo solid state reaction to form urea?
[SSC MTS (18 October 2024, Shift 1)]
(A) Ammonium cyanate
(B) Ammonium phosphate
(C) Ammonium acetate
(D) Ammonium nitrate
Answer: (A) Ammonium cyanate
Explanation: Friedrich Wöhler famously prepared urea by rearranging ammonium cyanate in 1828. The reaction demonstrated that an organic compound could be synthesised from inorganic starting materials. Urea subsequently became one of agriculture’s most widely used concentrated nitrogen fertilisers.
Q21. Microbes like Rhizobium, Nitrosomonas and Nitrobacter are used for:
[SSC CGL Tier I (12 September 2024, Shift 1)]
(A) Nitrogen cycling
(B) Carbon cycling
(C) Water cycling
(D) Sulphur cycling
Answer: (A) Nitrogen cycling
Explanation: Rhizobium helps fix atmospheric nitrogen in legume root nodules. Nitrosomonas oxidises ammonium to nitrite, and Nitrobacter converts nitrite to nitrate. Together these microbes participate in the nitrogen cycle, which is fundamental to natural soil fertility and plant nutrition.
Q20. The aquatic plant commonly used as bio fertilizer in the water-logged rice field is —
[UPPSC PCS Prelims GS Paper I, Set C (14 May 2023)]
(A) Wolfia
(B) Azolla
(C) Trapa
(D) Lemna
Answer: (B) Azolla
Explanation: Azolla is a floating aquatic fern associated with the nitrogen-fixing cyanobacterium Anabaena azollae. In paddy fields this symbiosis adds biologically fixed nitrogen to the farming system. Azolla can be grown and incorporated into soil as a green biofertiliser.
Q19. ________ is used to manufacture fertilizers, synthetic fibers, plastics, adhesives, paints, and dyes.
[SSC GD Constable, 2022 cycle (30 January 2023, Shift 3)]
(A) Nitric acid
(B) Soda ash
(C) Alkalis
(D) Sulphuric acid
Answer: (D) Sulphuric acid
Explanation: Sulphuric acid is a major industrial chemical used to process phosphate rock and manufacture phosphate fertilisers. It also serves numerous chemical industries, so industrial consumption is often viewed as an indicator of development. Soda ash and alkalis have different principal manufacturing applications.
Q18. Which of the following statements regarding fertilizers is FALSE?
[RRB Group D (25 August 2022, Shift 3)]
(A) Must be properly stored
(B) Leaches out with rains or irrigation water
(C) Never contaminate air and water
(D) Nutrient amounts calculated in advance can be applied
Answer: (C) Never contaminate air and water
Explanation: Fertilisers can pollute air and water when applied excessively or mishandled. Rainwater runoff and leaching move nutrients into streams and groundwater, encouraging eutrophication. Some fertiliser nitrogen is also lost as ammonia or nitrous oxide. Storage and carefully calculated application reduce these effects.
Q17. Which of the following statements is correct?
I. Converting plant and animal waste including that from kitchen into manure is called composting.
II. The method of making compost from kitchen garbage using redworms is called vermicomposting.
[SSC MTS (14 July 2022, Shift 3)]
(A) Only I is correct.
(B) Neither I nor II is correct.
(C) Both I and II are correct.
(D) Only II is correct.
Answer: (C) Both I and II are correct.
Explanation: Composting converts biodegradable organic wastes into manure through microbial decomposition. Vermicomposting specifically uses earthworms, such as redworms, to break down waste into nutrient-rich castings. Both processes recycle refuse, support soil structure and provide natural sources of plant nutrients.
Q16. The systematic name of which compound is nitrogen trihydride that is widely used in many industrial processes, and as a fertiliser and refrigerant?
[SSC CHSL, 2021 cycle (3 June 2022, Shift 2)]
(A) Potash
(B) Urea
(C) Phosphine
(D) Ammonia
Answer: (D) Ammonia
Explanation: Ammonia has formula NH₃ and is sometimes called nitrogen trihydride. It can be applied directly as a nitrogen fertiliser or converted into urea and ammonium salts. Industrial ammonia is chiefly synthesised from nitrogen and hydrogen by the Haber–Bosch process.
Q15. Which one of the following statements about fertilizers is not correct?
[UPSC NDA-I General Ability Test (10 April 2022)]
(A) Urea is a phosphorus-containing fertilizer.
(B) Application of fertilizer to the soil increases fertility of the soil.
(C) Urea can be prepared by action of ammonia and carbon dioxide under high pressure and at high temperature.
(D) Urea contains more nitrogen than other fertilizers.
Answer: (A) Urea is a phosphorus-containing fertilizer.
Explanation: Urea, CO(NHâ‚‚)â‚‚, contains carbon, hydrogen, nitrogen and oxygen but no phosphorus. It is manufactured commercially from ammonia and carbon dioxide under elevated pressure and temperature. Its high nitrogen fraction, about 46%, makes it an important concentrated nitrogenous fertiliser.
