Consider the following statements: 1. NPK fertilizers contain only macronutrients. 2. Zinc and Boron are micronutrients for plants. Which is/are correct? MCQ with Answer and Explanation
Consider the following statements: 1. NPK fertilizers contain only macronutrients. 2. Zinc and Boron are micronutrients for plants. Which is/are correct?
A. 2 only
B. Both 1 and 2
C. 1 only
D. Neither 1 nor 2
Answer: Option B
Solution (By JKSSB Mock Tests)
NPK fertilizers supply the three primary macronutrients: Nitrogen (N), Phosphorus (P), and Potassium (K). Plants also require trace elements (micronutrients) in very small amounts for proper growth, such as Iron, Manganese, Zinc, Copper, Boron, and Molybdenum. Both statements are factually correct.
Explanation:
CH₄ (methane) has covalent bonds where carbon shares electrons with four hydrogen atoms. CaO (Ca²⁺ O²⁻), KCl, and NaF are ionic compounds formed by electron transfer between a metal and a non-metal. Ionic bonds form when electronegativity difference is large. Covalent bonds typically between non-metals with similar electronegativities.
Explanation:
Soap (sodium carboxylate) reacts with Ca²⁺ and Mg²⁺ ions present in hard water to form an insoluble precipitate known as scum. This reduces lathering and wastage of soap. Synthetic detergents do not form scum because their calcium/magnesium salts are soluble.
Explanation:
Permanent hardness is due to dissolved sulfates and chlorides of calcium and magnesium. Boiling does not remove it. It requires chemical treatment (washing soda, ion exchange) or distillation. Temporary hardness (bicarbonates) is removed by boiling.
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