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Class 10 · Science · Easy
→Methyl orange is red and phenolphthalein is colourless in a solution. What should be added to neutralise it?
Class 10 · Science · Easy
→Phenolphthalein turns pink and methyl orange appears yellow in a solution. What is the nature of the solution?
Class 10 · Science · Medium
→Why is it chemically unsafe to store curd or pickle in a copper vessel?
Class 10 · Science · Medium
→What chemical reason explains the effect of acid rain on marble?
Class 10 · Science · Medium
→Why can adding organic matter improve highly basic soil?
Class 10 · Science · Medium
→Why does adding slaked lime to acidic soil increase pH?
Class 10 · Science · Medium
→How does basic toothpaste help protect teeth?
Class 10 · Science · Medium
→Why does enamel risk increase when tooth pH goes below 5.5?
Class 10 · Science · Medium
→Baking powder reacts little in a dry container but produces gas in moist dough. What is the reason?
Class 10 · Science · Medium
→On heating baking soda, the gas formed turns lime water milky. What nature of solution does the remaining solid form?
Class 10 · Science · Medium
→Why is it necessary to keep the products separate in the chlor-alkali process?
Class 10 · Science · Medium
→In the chlor-alkali process, what is the correct pair of gas at cathode and gas at anode?
Class 10 · Science · Medium
→Aqueous sugar solution does not conduct electricity while salt solution does. What is the main reason?
Class 10 · Science · Medium
→Sodium chloride solution has pH near 7 but still conducts electricity. What does this prove?
Class 10 · Science · Medium
→Blue copper sulphate becomes white on heating and blue again on adding water. What does this prove?
Class 10 · Science · Medium
→Why is it necessary to heat gypsum only at controlled temperature?
Class 10 · Science · Hard
→Why does bleaching powder lose effectiveness when kept in a moist open place?
Class 10 · Science · Hard
→Why can sodium hydroxide become impure when kept in open air?
Class 10 · Science · Hard
→Ammonia gas turns moist red litmus blue but has no effect on dry red litmus. What does this prove?
Class 10 · Science · Hard
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