This quiz works best with JavaScript enabled. Home > Class 10 > Class 10 Science Chapter 1 Chemical Reactions And Equations – Quiz 1 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 10 Science Chapter 1 Chemical Reactions And Equations Quiz 1 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Which of the following answers will balance the equation below? ..... K + ..... Br$_{2}$ ..... > ..... KBr A) 2, 1, 1. B) 2, 3, 2. C) 2, 1, 2. D) 1, 2, 3. Show Answer Correct Answer: C) 2, 1, 2. 2. Which of the following is true regarding the law of conservation of mass? A) It dictates that the number of molecules on each side of a chemical equation must be the same. B) It dictates that the number of atoms of each element must be the same on both sides of a chemical equation. C) It states that the mass of the reactants must remain constant in order for a chemical reaction to proceed. D) It does not apply to chemical reactions. Show Answer Correct Answer: B) It dictates that the number of atoms of each element must be the same on both sides of a chemical equation. 3. When magnesium ribbon is burned it forms a white powder called A) Magnesium carbonate. B) Magnesium oxide. C) All the above. D) None of the above. Show Answer Correct Answer: B) Magnesium oxide. 4. Which of the following gases can be used for storage of fresh sampel of an oil for a long time? A) Carbon dioxide or oxygen. B) Nitrogen or helium. C) Helium or oxygen. D) Nitrogen or oxygen. Show Answer Correct Answer: B) Nitrogen or helium. 5. One of the following processes does not involve a chemical reaction. That is: A) Melting of candle wax when heated. B) Burning of candle wax when heated. C) Digestion of food in our stomach. D) Ripening of banana. Show Answer Correct Answer: A) Melting of candle wax when heated. 6. Magnesium ribbon before burning is cleaned by sandpaper. Why? A) To remove the layer of magnesium oxide. B) To remove the layer of magnesium carbonate. C) All the above. D) None of the above. Show Answer Correct Answer: B) To remove the layer of magnesium carbonate. 7. Which of the following is a displacement reaction? A) CaCO3 $\rightarrow$ CaO + CO2. B) Fe + Cuso4 $\rightarrow$ Feso4 + with. C) Na + Cl2 $\rightarrow$ 2NaCl. D) 2H2 + O2 $\rightarrow$ 2H2O. Show Answer Correct Answer: B) Fe + Cuso4 $\rightarrow$ Feso4 + with. 8. Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is: A) 1:1. B) 2:1. C) 4:1. D) 1:2. Show Answer Correct Answer: B) 2:1. 9. When two substances were combined, bubbles were produced and the temperature dropped. This most likely means that: A) A chemical reaction took place. B) The two substances had low boiling points. C) One substance dissolved in the other. D) The two substances are non-reactive. Show Answer Correct Answer: A) A chemical reaction took place. 10. Which one of the following is a balanced equation? A) H2+O2 >H2O. B) Prepare+oh > prepare. C) 2H2+O2 >2H2O. D) I+aa > I investigate. Show Answer Correct Answer: C) 2H2+O2 >2H2O. 11. Give the ratio in which hydrogen and oxygen are present in water by volume. A) 1:2. B) 1:1. C) 2:1. D) 1:8. Show Answer Correct Answer: A) 1:2. 12. Corrosion of iron is called ..... A) Rusting. B) Greasing. C) Anodizing. D) Galvanziation. Show Answer Correct Answer: A) Rusting. 13. An iron nail is placed in a solution of copper sulphate. The nail is taken out after 10 minutes. The nail will be found to be covered with: A) Brown deposit. B) Black deposit. C) White deposit. D) Yellow deposit. Show Answer Correct Answer: A) Brown deposit. 14. Which of the following is a balanced chemical equation? A) H$_{2}$O$_{2}$ $\rightarrow$ H$_{2}$O + O$_{2}$. B) 2Fe$_{2}$O$_{3}$ + 3C $\rightarrow$ 4Fe + 3CO$_{2}$. C) SO$_{2}$ + O$_{2}$ + 2H$_{2}$O $\rightarrow$ 4H$_{2}$SO$_{4}$. D) 2Mg + HCl $\rightarrow$ MgCl$_{2}$ + H$_{2}$. Show Answer Correct Answer: B) 2Fe$_{2}$O$_{3}$ + 3C $\rightarrow$ 4Fe + 3CO$_{2}$. 15. Which option denotes a double displacement reaction? A) A + B + C. B) A + B $\rightarrow$ C. C) AC + BD $\rightarrow$ AD + BC. D) And + b $\rightarrow$ ab + c. Show Answer Correct Answer: C) AC + BD $\rightarrow$ AD + BC. 16. How many elements are in C$_{6}$H$_{12}$O$_{6}$? A) 1. B) 2. C) 3. D) 4. Show Answer Correct Answer: C) 3. 17. A substance added to food containing fats and oils is called: A) Oxidant. B) Rancid. C) Coolant. D) Antioxidant. Show Answer Correct Answer: D) Antioxidant. 18. A substance 'X' is used in white-washing and is obtained by heating limestone in the absence of air. Identify 'X'. A) $ Caocl_2 $. B) $Ca\left(OH\right)_2$. C) $CaO$. D) $CaCO_3$. Show Answer Correct Answer: A) $ Caocl_2 $. 19. Which among the following statements is true regarding silver chloride? A) It turns grey due to the formation of silver. B) It sublimates to form silver. C) It decomposes to release chlorine gas. D) It oxidizes to form silver. Show Answer Correct Answer: A) It turns grey due to the formation of silver. 20. Which of these is NOT a sign of a chemical change: A) Color change. B) Unexpected temperature change. C) Phase change. D) Gas/bubbles/odor. Show Answer Correct Answer: C) Phase change. 21. Which of the following does show an oxidation reaction? A) Gain of oxygen. B) Loss of oxygen. C) Gain of hydrogen. D) None of the above. Show Answer Correct Answer: A) Gain of oxygen. 22. What is is used in balck and white photography A) Silver chlorde. B) Silver bromide. C) Silver nitrate. D) None of the above. Show Answer Correct Answer: B) Silver bromide. 23. Which of the following is not a physical change? A) Boiling of water to give water vapour. B) Melting of ice to give water. C) Dissolution of salt in water. D) Combustion of Liquefied Petroleum Gas (LPG). Show Answer Correct Answer: D) Combustion of Liquefied Petroleum Gas (LPG). 24. Which one of the following processes involve chemical reactions? A) Storing of oxygen gas under pressure in a gas cylinder. B) (b) Liquefaction of air. C) (c) Keeping petrol in a china dish in the open. D) (d) Heating copper wire in presence of air at high temperature. Show Answer Correct Answer: D) (d) Heating copper wire in presence of air at high temperature. 25. When we drop some zinc granules in copper sulphate solution, the colour of solution changes from blue to ..... A) White. B) Green. C) Colourless. D) Violet. Show Answer Correct Answer: C) Colourless. 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