Which gas is evolved when zinc granules react with dilute sulfuric acid?
A. Hydrogen
B. Carbon dioxide
C. Oxygen
D. Sulfur dioxide
Answer: Option A
Solution (By JKExamLibrary)
Zn + H₂SO₄ → ZnSO₄ + H₂↑. Hydrogen gas is released, which burns with a pop sound. This is a test for hydrogen. Metals above hydrogen in reactivity series displace it from acids. Dilute H₂SO₄ with Zn produces H₂; with Cu, no reaction.
Explanation:
Acid rain results from SO₂ and NOₓ (from burning fossil fuels) reacting with water vapor to form sulfuric and nitric acids. Normal rain is slightly acidic (pH ~5.6) due to CO₂ forming carbonic acid, but acid rain has pH < 5.6. Effects include corrosion of monuments (Taj Mahal), damage to aquatic life, and soil acidification. CO₂ causes global warming, not primarily acid rain.
Explanation:
Urea (CO(NH₂)₂) is a nitrogenous fertilizer with the highest nitrogen content (about 46%). Superphosphate provides phosphorus, muriate of potash (KCl) provides potassium, and gypsum (CaSO₄·2H₂O) is a soil conditioner providing calcium and sulfur, not primary NPK nutrients.
Explanation:
Mass number (A) = number of protons (Z) + number of neutrons (N). Electrons have negligible mass and are not counted. It is the total number of nucleons. Example: ¹²C has 6 protons + 6 neutrons = 12. Isotopes have same Z but different A due to varying N. Atomic mass (weight) is the weighted average.
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