Chemical Reactions and Equations MCQ Class 10

MCQ Questions for Class 10 Science Chemical Reactions and Equations with Answers

Q1. Which of the following statements is true regarding chemical reaction ?

(a) It is the process in which new substances with new properties are formed.

(b) It is the process in which new chemicals with new substances are formed.

(c) It is the process in which new chemicals with new properties are formed.

(d) the substances which take part in a chemical reaction are known as reactants.

Ans. It is the process in which new substances with new properties are formed.

Q2. The substance produced as a result of chemical reaction are called as

(a) Substance

(b) Chemical

(c) Products

(d) None of these

Ans. Products

Q3. A _________________ has equal number of atoms of element in the reactant and product.

(a) Chemical equation

(b) Balanced chemical equation

(c) Unbalanced chemical equation

(d) None of these

Ans. Balanced chemical equation

Q4. Which of the following statements is correct regarding unbalanced chemical equations ?

(a) An unbalanced chemical equation has an unequal number of atoms of one or more elements in only recatends sides.

(b) An unbalanced chemical equation has an unequal number of atoms of one or more elements in only the product side.

(c) An unbalanced chemical equation has an unequal number of atoms of one or more elements in the reactant and products.

(d) None of the above

Ans. an unbalanced chemical equation has an unequal number of atoms of one or more elements in the reactant and products.

Q5. Sodium reacts with water to give sodium hydroxide and hydrogen. Which of the following chemical reactions is balanced regarding the above statement ?

(a) Na+2H2O – 2NaOH + H2

(b) Na + H2O – NaOH + H2

(c) 4Na + 4H2O – 4NaOH + H2

(d) 2Na + 2H2O – 2NaOH + H2

Ans. 2Na + 2H2O – 2NaOH + H2

Q6. Which of the following statements is correct regarding “characteristic of a chemical reaction” ?

(1) evolution of gas 

(2) formation of precipitate 

(3) change in temperature 

(4) change in color 

(5) change in physical state

(a) (1) and (2) is correct statements

(b) (3),(4) and (5) is correct statements

(c) All of the above statement is correct

(d) None of the above statement is correct

Ans. All of the above statement is correct

Q7. A _____________ is a solid substance or product which separates out from the solution during a chemical reaction.

(a) Substance

(b) Physical state

(c) Precipitate

(d) None of these

Ans. Precipitate

Q8. Those reaction in which compound react by exchange of ions to form New compounds are known as

(a) Combination reaction

(b) Decomposition reaction

(c) Displacement reaction

(d) Double displacement reaction

Ans. Double displacement reaction

Q9. Which of the following statements about the given reaction are correct?

CuO + H2 – Cu + H2O

(1) copper oxide is acting as reducing agent

(2) copper is getting reduced

(3) Hydrogen is acting as oxidizing agent

(4) Hydrogen is getting oxidized

(a) (1) and (2) is correct statements

(b) (2) and (3) is correct statements

(c) (1) and (3) is correct statements

(d) (2) and (4) is correct statements

Ans. (2) and (4) is correct statements

Q10. A Shiny brown coloured element ‘X’ on heating in air becomes black in color named the element ‘X’ and the black color compound formed ?

(a) element X is an ammonium. The black color compound is ammonium oxide. NH4 + O2 – (NH4)2O 

(b) limit X is zinc. The black color compound is zinc oxide. Zn2 + O2 – ZnO

(c) element X is magnesium. The black color compound is magnesium oxide. Mg2 + O2 – MgO

(d) element X is copper, the black color compound is copper oxide. Cu + O2 – Cu2O

Ans. element X is copper the black color compound is copper oxide. Cu + O2 – Cu2O

Q11. Which of the following are exothermic reactions ?

(1) Burning of natural gas 

(2) Photosynthesis

(3) Respiration 

(4) Decomposition of calcium carbonate 

(5) Electrolysis of water

(a) (1) and (2) is exothermic reaction

(b) (3) and (4) is exothermic reaction

(c) (1) and (5) is exothermic reaction

(d) (1) and (3) is exothermic reaction

Ans.  (1) and (3) is exothermic reaction

Q12. When a solution of potassium iodine is added to a solution of lead nitrate then what type of precipitate is observed ?

(a) then yellowish color solid is observed

(b) then white color solid is observed

(c) then grayish color solid is observed

(d) then reddish brown color solid is observed

Ans. then yellowish color solid is observed

Q13. What do you observe when silver bromide is exposed to sunlight?

(a) It decomposed to form bromine metal and silver vapors 

(b) It decomposed to form danger chemical, silver metal and bromine vapors

(c) It decomposed to form silver metal and bromine vapors

(d) we observed there is nothing happening with silver bromine when it is exposed to sunlight.

Ans. It decomposed to form silver metal and bromine vapors

Q14. Which of the following statements are correct regarding oxidation ? 

(1) addition of oxygen 

(2) removal of oxygen

(3) addition of hydrogen

(4) removal of hydrogen    

(5) lose of electron

(6) gain of electron

(a) (1), (2) and (3) are the correct statements

(b) (4), (5) and (6) are the correct statements

(c) (1), (4) and (5) are the correct statements

(d) (2), (3) and (6) are the correct statements

Ans. (1), (4) and (5) are the correct statements

Q15. What do you mean by Reducing agent ?

(a) The substance getting reduced is known as a reducing agent.

(b) The substance getting oxidized is known as a reducing agent.

(c) The substance getting both reduced and oxidized is known as reducing agent

(d) Removal of oxygen, Addition of hydrogen and Gain of electrons are known as reducing agents.

Ans. The substance getting oxidized is known as a reducing agent.

Q16. Which among them are correct regarding this formula ?

ZnO + C – Zn + CO

(1) substance getting oxidized is C

(2) substance getting reduced is ZnO 

(3) Reducing agent is C

(4) Oxidizing agent is ZnO

(a) (1) and (2) is the correct statements

(b) (3) and (4) is the correct statements

(c) (1) and (3) is the correct statements

(d) All the above statements are correct

Ans. All the above statements are correct

Q17. Why does the color of copper sulfate change when an iron nail is dipped in it ?

(a) because iron is more reactive than copper so iron displaces copper from copper sulfate solution.

(b) because iron is less reactive than copper so iron displaces copper from copper sulfate solution.

(c) because both are metals so the color of copper sulfate changes when an iron nail is dipped in it.

(d) because sulfate is more reactive than copper and iron then it reacts with air and changes its color.

Ans. Because iron is more reactive than copper, iron displaces copper from copper sulfate solution.

Q18. Why is photosynthesis considered an endothermic reaction ?

(a) because green chlorophyll energy is observed by sunlight during this process.

(b) because the sunlight energy is absorbed by green plants during this process.

(c) because green plants prepare their food in the absence of sunlight during this process.

(d) because green plants release carbon dioxide in large amounts at night so it is considered an endothermic reaction.

Ans. because the sunlight energy is absorbed by green plants during this process.

Q19. Which among the following statements is incorrect regarding decomposition reaction ?

(1) In this reaction a compound splits into two or more simple substances is known as decomposition reaction.

(2) If the decomposition is carried out by the heat then it is known as thermal decomposition reaction.

(3) It also decomposes more reactive metal and decomposes with less reactive metal is known as decomposition reaction.

(a) (1) statement is incorrect regarding decomposition reaction

(b) (2) statement is incorrect regarding decomposition reaction

(c) (3) statement is incorrect regarding decomposition reaction

(d) (2) and (3) statements are incorrect regarding decomposition reaction

Ans. (3) statement is incorrect regarding decomposition reaction

Q20. __________ can be prevented by keeping food in an airtight container and refrigerator, it can be prevented by antioxidants to the food containing fat and oil.

(a) Corrosion

(b) Food Poisoning

(c) Rancidity

(d) None of these

Ans. Rancidity

Q21. Name two salts used in black and white photosynthesis ?

(a) AgCl and AgBr are the two salts that are used in black and white photography.

(b) NaCl and MgSO4 are the two salts that are used in black and white photography.

(c) KI and CuSO4 are the two salts that are used in black and white photography.

(d) CaCO3 and CH3COONa are the two salts that are used in black and white photography.

Ans. AgCl and AgBr are the two salts that are used in black and white photography.

Q22. What are Anti – Oxidants ?

(a) These are the substances which react with air and help in the oxidation process.

(b) These are substances which do not react with air and do not help in the oxidation process.

(c) These are the substances which are prevented by keeping food in an airtight container and refrigerator.

(d)  Anti – Oxidants are the fat and oil containing food with nitrogen gas.

Ans. These are substances which do not react with air and do not help in the oxidation process.

Q23. What are Neutralization Reactions?

(a) A neutralization reaction is when an acid reacts with the metal to form water and salt.

(b) A neutralization reaction is when a base reacts with a nonmetal to form water and salt.

(c) A neutralization reaction is when a chemical reaction happens to form water and salt.

(d) A neutralization reaction is when an acid and a base react to form water and salt.

Ans. A neutralization reaction is when an acid and a base react to form water and salt.

Q24. What happens when lead nitrate reacts with potassium iodide?

(a) They will not react

(b) a Large amount of hydrogen release

(c) Yellow precipitate of lead iodide and potassium nitrate will be produced

(d) Evolution of gas will occur

Ans. Yellow precipitate of lead iodide and potassium nitrate will be produced

Q25. On what chemical law, balancing of chemical equations is based?

(a) Balancing of a chemical equation is based on the law of Ideal gas law.

(b) Balancing a chemical equation is based on the law of conservation of momentum.

(c) Balancing a chemical equation is based on the law of conservation of mass.

(d) Balancing a chemical equation is based on the law of balance of electrons.

Ans. Balancing a chemical equation is based on the law of conservation of mass.

Q26. Name the gas that evolved when zinc reacts with dilute HCl.

(a) Hydrogen gas has evolved.

(b) Nitrogen gas has evolved.

(c) Carbonate gas has evolved.

(d) Water vapor has evolved.

Ans. Hydrogen gas has evolved.

Q27. Which of the following statements is correct regarding ‘Mass’?

(a) mass cannot be created but can be destroyed during a chemical reaction.

(b) mass can be created but nor be destroyed during a chemical reaction.

(c) mass neither be created nor be destroyed during a chemical reaction.

(d) mass be created or destroyed during a chemical reaction.

Ans. mass neither be created nor be destroyed during a chemical reaction.

Q28. Which of the following statements is incorrect?

(a) In a combination reaction two or more of Trans combined to form a new single substance.

(b) In a decomposition reaction a single substance decomposes to give two or more substances.

(c) In a displacement reaction more reactive metal displaces a less reactive metal.

(d) In double displacement reaction compounds do not exchange their ions to form a new compound

Ans. In double displacement reaction compounds do not exchange their ions to form a new compound

Q29. When carbon dioxide is passed through lime water,

(a) Calcium hydroxide is formed

(b) White precipitate of CaO is formed

(c) Lime water turns milky

(d) Color of lime water disappears.

Ans. Lime water turns milky

Q30. In writing chemical equations, the inclusion of state symbols shall be done while

(a) The equation has been balanced

(b) Correct chemical formula of reactants and products are written

(c) The equation is being balanced to fulfill the law of conservation of mass

(d) The chemical formulae of products and reactants have been changed to bring about quick balancing

Ans. The equation has been balanced

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