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Class 10 · Science · Hard
→In the reaction (2 ext{Al}+3 ext{CuCl}_2 ightarrow2 ext{AlCl}_3+3 ext{Cu} ), a student says that 1 mol of aluminium will produce 1 mol of copper. Which statement correctly corrects the error?
Class 10 · Science · Easy
→If substance A loses oxygen and substance B gains that oxygen, what is the correct sequence of changes in substances A and B?
Class 10 · Science · Hard
→In which of the following reactions does the same element undergo both oxidation and reduction simultaneously?
Class 10 · Science · Medium
→When copper(II) oxide is heated with hydrogen, copper is formed. Which process occurs to copper(II) oxide in this reaction?
Class 10 · Science · Hard
→Which statement correctly describes oxidation and reduction in the reaction \\(\mathrm{CuO + H_2 \rightarrow Cu + H_2O}\\)?
Class 10 · Science · Hard
→Which of the following equations represents a displacement reaction in which oxidation and reduction occur simultaneously?
Class 10 · Science · Medium
→Two aqueous solutions are mixed and a white insoluble solid and sodium chloride are formed. What could be the original solutions?
Class 10 · Science · Medium
→Metal A displaces metal B from a solution of its salt, and metal B displaces metal C from a solution of its salt. Which metal is the least reactive?
Class 10 · Science · Hard
→In the reaction \(\mathrm{CuO + H_2 \rightarrow Cu + H_2O}\), which reactant is the reducing agent?
Class 10 · Science · Hard
→What is the microscopic reason for fading of blue colour of copper sulphate solution?
Class 10 · Science · Hard
→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 · Medium
→What is the real purpose of adding a small amount of acid during electrolysis of water?
Class 10 · Science · Hard
→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 · Hard
→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 · Hard
→What is the most suitable reason for storing silver bromide in a dark-coloured bottle?
Class 10 · Science · Medium
→Silver chloride turns grey in sunlight. This change is related to which energy and which product?
Class 10 · Science · Hard
→Which is the correct pair of solid residue and brown gas formed on heating lead nitrate?
Class 10 · Science · Medium
→The brown gas on heating lead nitrate indicates the presence of which substance?
Class 10 · Science · Hard
→Which solid product is formed on thermal decomposition of calcium carbonate?
Class 10 · Science · Hard
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