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Class 10 · Science
→A student measures the pH of four solutions: 2, 6, 7, and 11. Which solution will have the highest hydroxide ion concentration?
Class 10 · Science
→When acid is added to a metal carbonate, the evolved gas turns lime water milky. What is the correct identification and reason?
Class 10 · Science
→Which product is not formed when baking soda is heated?
Class 10 · Science
→Methyl orange turns red in a colourless solution. On adding sodium hydroxide slowly, the colour changes to yellow. What process does this indicate?
Class 10 · Science
→A white powder releases heat when mixed with water and forms a milky solution. Passing carbon dioxide through this solution gives a white precipitate. What can the powder be?
Class 10 · Science
→If sodium hydroxide solution is left exposed to air, which substance may form over time?
Class 10 · Science
→To protect tooth enamel from decay, pH should be prevented from falling below which approximate value?
Class 10 · Science
→Phenolphthalein turns pink in an aqueous solution of sodium carbonate. What is the most appropriate reason?
Class 10 · Science
→When water is added to calcium oxide, a large amount of heat is released and calcium hydroxide is formed. What is the correct classification of this reaction?
Class 10 · Science
→An acidic solution has pH 2 and another acidic solution has pH 5. How many times higher is the hydrogen ion concentration in the first solution?
Class 10 · Science
→A solution turns red litmus blue. When ammonium chloride is added to it and heated, a pungent-smelling gas is evolved. Which gas is it?
Class 10 · Science
→When excess carbon dioxide gas is passed through sodium hydroxide solution, what can finally be the main product?
Class 10 · Science
→Dry hydrogen chloride gas is passed over dry blue litmus paper and no colour change occurs. The same gas is passed over moist blue litmus paper and it turns red. What is the reason?
Class 10 · Science
→Dilute sulphuric acid is added to zinc pieces in a test tube. The evolved gas burns with a pop sound near a burning splint. What is the correct chemical reason?
Class 10 · Science
→A farmer has highly acidic soil and wants to reduce its acidity without harming crop roots. Which substance is most suitable?
Class 10 · Science
→An unknown salt gives brown fumes on heating and leaves a yellow solid that turns white on cooling. Which salt does this indicate?
Class 10 · Science
→A student adds phenolphthalein to a colourless solution and observes a pink colour. Then dilute hydrochloric acid is added slowly and the pink colour disappears. Which conclusion is most correct?
Class 10 · Science
→A student added an acidic substance to already acidic soil. What effect is likely on plant growth?
Class 10 · Science
→Why is it not suitable to leave sodium hydroxide open in air?
Class 10 · Science
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