Excessive use of chemical fertilizers can lead to:
A. Improvement of soil texture.
B. Increased soil fertility indefinitely.
C. Eutrophication of water bodies.
D. Increase in beneficial soil microbes.
Answer: Option C
Solution (By JKSSB Mock Tests)
Excessive use of chemical fertilizers, especially those containing nitrogen and phosphorus, can lead to runoff into water bodies. This causes eutrophication (algal blooms), which depletes oxygen in the water and kills aquatic life. It also degrades soil health and kills beneficial microbes over time.
Explanation:
Sodium carbonate decahydrate (washing soda) is prepared by dissolving soda ash (anhydrous Na₂CO₃) in water and allowing it to crystallise. Heating would remove water of crystallization (efflorescence). Adding acid would decompose it. Electrolysis would produce NaOH and Cl₂ from brine, not washing soda directly.
Explanation:
Gypsum (CaSO₄·2H₂O) is added to clinker to control the rapid reaction of tricalcium aluminate with water, which would otherwise cause flash (quick) setting. Gypsum slows down the hydration of C₃A, thus increasing the setting time and allowing workability. Without gypsum, cement would set almost immediately upon mixing with water, making placement impossible.
Explanation:
Polycarbonate is a tough, transparent thermoplastic used in bulletproof glass, CDs, and lenses. Polyethylene is for bags; PVC for pipes; Bakelite is thermoset.
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