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Class 10 · Science
→In an experiment, copper powder forms black CuO when heated in air. When H2 is passed over it on heating, reddish-brown copper is obtained again. Which is the correct explanation of these changes?
Class 10 · Science
→In the thermite reaction \(Fe_2O_3 + 2Al \rightarrow Al_2O_3 + 2Fe\), which substance is reduced?
Class 10 · Science
→A student writes the reaction on placing an iron nail in aqueous copper sulfate solution as: \(2Fe + 3CuSO_4 \rightarrow Fe_2(SO_4)_3 + 3Cu\). What correction is required in the equation?
Class 10 · Science
→When an iron nail is placed in a blue copper sulphate solution, the solution turns green and a reddish-brown coating forms on the nail. What type of reaction is this?
Class 10 · Science
→In the reaction \(2\mathrm{FeCl_3} + \mathrm{SnCl_2} \rightarrow 2\mathrm{FeCl_2} + \mathrm{SnCl_4}\), which substance is the reducing agent?
Class 10 · Science
→When a zinc strip is placed in a blue copper sulphate solution, which observation indicates a displacement reaction?
Class 10 · Science
→A student states that the reaction \(2\mathrm{Mg}+\mathrm{O}_2\rightarrow2\mathrm{MgO}\) is not a displacement reaction because no element replaces another element from a compound. The student is correct because this reaction is which type of reaction?
Class 10 · Science
→Why does oily food kept in warm, open air spoil quickly?
Class 10 · Science
→A student places an iron nail in a blue copper sulphate solution. After some time, a reddish-brown coating appears on the nail and the solution turns light green. What type of reaction is this?
Class 10 · Science
→In which of the following reactions does a more reactive metal displace a less reactive metal from its salt solution?
Class 10 · Science
→Painting and oiling prevent rusting based on which common principle?
Class 10 · Science
→Under which condition will iron rust the most?
Class 10 · Science
→What is the correct order of the processes in which hydrogen is removed from a substance and then added to a substance?
Class 10 · Science
→When aqueous barium chloride and sodium sulfate are mixed, which pair of ions combines to form the white precipitate?
Class 10 · Science
→Which of the following is a double displacement reaction that forms a precipitate?
Class 10 · Science
→In the reaction between copper(II) oxide and hydrogen, the formation of water indicates the oxidation of which substance?
Class 10 · Science
→When copper(II) oxide is heated with hydrogen gas, what change occurs in the copper(II) oxide?
Class 10 · Science
→A student heated 12.0 g of calcium carbonate in an open crucible and obtained 6.7 g of solid. Which evaluation is correct?
Class 10 · Science
→How are products predicted in a double displacement reaction?
Class 10 · Science
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