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Class 10 · Science
→Why does a reddish-brown coating form on an iron nail and the solution turn green when the nail is placed in copper sulphate solution?
Class 10 · Science
→What is the real purpose of adding a small amount of acid during electrolysis of water?
Class 10 · Science
→A student heated calcium carbonate in an open test tube. The mass of the solid decreased after heating, so the student concluded that the law of conservation of mass is incorrect. What is the correct correction to this conclusion?
Class 10 · Science
→During the electrolysis of water, at the same temperature and pressure, if the volume of hydrogen gas obtained is 20 mL, what will be the volume of oxygen gas?
Class 10 · Science
→What is the most suitable reason for storing silver bromide in a dark-coloured bottle?
Class 10 · Science
→Silver chloride turns grey in sunlight. This change is related to which energy and which product?
Class 10 · Science
→Which is the correct pair of solid residue and brown gas formed on heating lead nitrate?
Class 10 · Science
→The brown gas on heating lead nitrate indicates the presence of which substance?
Class 10 · Science
→Which solid product is formed on thermal decomposition of calcium carbonate?
Class 10 · Science
→The gas evolved on heating calcium carbonate turns lime water milky. Which gaseous product does this confirm?
Class 10 · Science
→In the reaction of calcium oxide with water, only one product is formed and heat is released. What is the correct combined classification of this reaction?
Class 10 · Science
→Why is it incorrect to change the subscripts in the formula of a compound while balancing a chemical equation?
Class 10 · Science
→In the balanced equation for burning magnesium, \(2\mathrm{Mg}+\mathrm{O}_2\rightarrow2\mathrm{MgO}\), how many oxygen atoms are present on the product side?
Class 10 · Science
→In the balanced chemical equation 2H₂ + O₂ → 2H₂O for the formation of water, how many hydrogen atoms are present in total on the product side?
Class 10 · Science
→If a gas is produced during a chemical reaction, what precaution should be taken while verifying the law of conservation of mass?
Class 10 · Science
→In a closed container, a total of 20 g of reactants undergo a reaction to form products, and any gas produced remains inside the container. What will be the total mass of the products?
Class 10 · Science
→In the reaction CuO + H₂ → Cu + H₂O, which is the correct identification of oxidation and reduction?
Class 10 · Science
→In which situation will checking conservation of mass be most reliable?
Class 10 · Science
→In the reaction \(CuO + H_2 \rightarrow Cu + H_2O\), which substance is the reducing agent?
Class 10 · Science
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