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Class 10 · Science · Hard
→In the thermite reaction \(Fe_2O_3 + 2Al \rightarrow Al_2O_3 + 2Fe\), which substance acts as the reducing agent?
Class 10 · Science · Hard
→When an iron nail is placed in copper sulphate solution, which substance is deposited on the surface of the nail?
Class 10 · Science · Medium
→Which problem is solved by adding a small amount of acid during electrolysis of water?
Class 10 · Science · Hard
→Which correctly identifies oxidation and reduction in the following reaction? \(\mathrm{Zn + CuSO_4 \rightarrow ZnSO_4 + Cu}\)
Class 10 · Science · Hard
→During electrolysis of water, at the same temperature and pressure, if the volume of oxygen collected is 7 mL, what volume of hydrogen will be collected?
Class 10 · Science · Hard
→What is the scientific reason for storing silver bromide in a dark-coloured bottle?
Class 10 · Science · Hard
→When silver chloride is exposed to sunlight, it turns grey. What is the main reason for this colour change?
Class 10 · Science · Hard
→Why is it incorrect to identify the brown fumes evolved on heating lead nitrate as oxygen?
Class 10 · Science · Hard
→When lead nitrate is heated, a solid residue and a brown gas are formed. Which pair is correct?
Class 10 · Science · Hard
→In the reaction \(CuO + H_2 \rightarrow Cu + H_2O\), which statement about oxidation and reduction is correct?
Class 10 · Science · Hard
→When water is added to calcium oxide, calcium hydroxide is formed and heat is released. What type of reaction is this?
Class 10 · Science · Easy
→When a single compound breaks down into two or more simpler substances on heating, what type of reaction is it?
Class 10 · Science · Hard
→In the reaction of magnesium with oxygen, if 2 formula units of magnesium oxide are formed, how many \(\mathrm{O_2}\) molecules are needed to balance the equation?
Class 10 · Science · Hard
→If the product side of a balanced chemical equation contains two water molecules, \(2\mathrm{H_2O}\), what total number of hydrogen atoms must be present on the reactant side?
Class 10 · Science · Hard
→What happens if the subscripts in the chemical formula of a compound are changed while balancing a chemical equation?
Class 10 · Science · Hard
→Limestone, \(\mathrm{CaCO_3}\), is heated in a sealed container and decomposes into calcium oxide and carbon dioxide. If the carbon dioxide does not escape, what is the correct conclusion about the total mass of substances before and after the reaction?
Class 10 · Science · Hard
→In an unknown process, a substance with new properties was formed, and the total mass in a closed container was the same before and after the process. What is the most appropriate conclusion?
Class 10 · Science · Hard
→Which of the following reaction is an example of both a displacement reaction and a redox reaction?
Class 10 · Science · Medium
→Which of the following reaction is both a displacement reaction and a redox reaction?
Class 10 · Science · Hard
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