Minerals support industries, agriculture and daily life. Iron makes steel, coal and petroleum provide energy, while copper and bauxite aid electrical and industrial production. Fertilizer minerals improve farming. Gold and silver serve trade, ornaments and economic development globally.
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Correct option – B (I and III). Aluminium oxide and zinc oxide are amphoteric and react with both dilute HCl and aqueous NaOH. Calcium oxide is basic (reacts with acid) and SO₂ is acidic (reacts with base). cbse sample paper 2025 ...
Correct option – B. Iron nail in P (CuSO₄) undergoes displacement: copper ions reduced to copper metal, giving a brownish coating; in Q (AgNO₃) iron displaces silver, producing a silver coating on the nail during the reaction. cbse sample paper 2025 ...
Correct option – D. Sodium hydroxide. Among the options, NaOH is a strong, highly soluble base producing a high concentration of OH⁻ in solution; magnesium hydroxide is sparingly soluble and both acids give low pH values generally. cbse sample paper 2025 ...
Correct option – B. When excess CO₂ passes through limewater, the initially formed insoluble calcium carbonate (which causes milkiness) reacts further with CO₂ and water to form soluble calcium bicarbonate, clearing the milkiness from the solution completely. cbse sample paper 2025 ...