Search questions
Choose which content to search, then combine terms with AND or OR.
Class 10 · Science · Hard
→Which of the following reaction is both a combination reaction and an oxidation-reduction reaction?
Class 10 · Science · Hard
→Which change is the clearest indication that a chemical reaction has occurred?
Class 10 · Science · Hard
→Which statement correctly describes the difference between a skeletal chemical equation and a balanced chemical equation?
Class 10 · Science · Easy
→Which of the following correctly matches a state symbol with the state of a substance?
Class 10 · Science · Easy
→If an upward arrow ↑ is written after a product in a chemical equation, which observation does it indicate?
Class 10 · Science · Easy
→A product written with a downward arrow in a chemical equation will have which property?
Class 10 · Science · Hard
→In an unknown chemical reaction, a gas was evolved and the container became cold. Which conclusion is the most cautious?
Class 10 · Science · Hard
→Why should a final conclusion about a chemical reaction not be drawn from colour change alone?
Class 10 · Science · Hard
→When an iron nail is kept in a blue copper sulphate solution for some time, the solution turns light green and a reddish-brown coating forms on the nail. Which is the correct explanation for this observation?
Class 10 · Science · Hard
→Why is digestion of food a chemical change, whereas chewing food is mainly a physical change?
Class 10 · Science · Hard
→What does writing sunlight above the arrow in the following photosynthesis equation indicate? \(6CO_2 + 6H_2O \xrightarrow{\text{sunlight}} C_6H_{12}O_6 + 6O_2\)
Class 10 · Science · Hard
→Which fact should be considered while identifying a similarity between respiration and combustion?
Class 10 · Science · Hard
→What type of reaction is represented by the following general equation? \[ A+B\rightarrow C+\text{heat} \]
Class 10 · Science · Hard
→If, in a reaction, a single compound absorbs heat and forms two or more products, what is the most appropriate classification of the reaction?
Class 10 · Science · Hard
→If the reaction mixture is not heated externally, which observation strongly suggests an exothermic reaction?
Class 10 · Science · Medium
→During a chemical reaction, which observation indicates that it is endothermic?
Class 10 · Science · Hard
→If a food packet contains more oxygen and is stored at a higher temperature, which problem becomes more likely?
Class 10 · Science · Medium
→Why are antioxidants useful in foods containing oils and fats?
Class 10 · Science · Medium
→How does filling nitrogen in chips packets affect the role of oxygen?
Class 10 · Science · Hard
→