Chemical Reaction and Chemical Bond 4 Chemical Reaction and Chemical Bond 4

1. What is a chemical reaction?

2. What are the substances that participate in a chemical reaction called?

3. Consider the following statements:

1. During a chemical reaction, new products are formed.
2. New atoms are formed during a chemical reaction.

Which of the above is/are incorrect?

4. Which of the following changes may occur during a chemical reaction?

5. Which of the following changes is not a chemical change?

6.Who takes part in a chemical reaction?

7.In which of the following changes does a chemical reaction take place?

1. Milk turning sour
2. Digestion of food in the human body
3. Boiling of water
4. Ripening of fruits
5. Burning of fuel

Choose the correct code:

8.Which statement about a chemical reaction is NOT correct?

Consider the following statements:

1. A chemical reaction can take place only in a laboratory.
2. No chemical reaction occurs in the human body.

Which of the above statements is/are correct?

10.As a result of a chemical reaction, which of the following does not change?

11.When chemical reactions are expressed in a brief form, it is called —

12.In a chemical equation, if the number of each type of atom on both the left and right sides is the same, then that chemical equation will be —

13.Which of the following information is not obtained from a chemical equation?

14.From a chemical equation, which of the following information about the reaction can be obtained?

15.The concept of a balanced chemical equation is in accordance with which scientific principle?

16.Consider the following chemical equation and choose the correct statement: 2CO+O2​⟶2CO2​

17.Which of the following statements about a chemical equation is false?

18.Which of the following is not a balanced chemical equation?

19.Which of the following statements is correct?

21.Which of the following is a combination reaction?

22.On heating calcium carbonate, calcium oxide and carbon dioxide are formed. This reaction is of which type?

23.Consider the following statements—

1. In a decomposition reaction, a chemical substance breaks down into two or more new substances.
2. A decomposition reaction takes place with the help of heat, light, or electrical energy.
3. A decomposition reaction is an endothermic reaction.

Which of the above statements is/are correct?

24.Which of the following is an exothermic reaction?

25.Consider the following statements—

1. The nature of a combination reaction is exothermic.
2. The nature of a decomposition reaction is endothermic.

Which of the above statements is/are correct?

27.During the electrolysis of a metal oxide, oxygen gas is released at —

29.When ammonia is burned in oxygen, which gas is formed?

30.What is obtained from the thermal decomposition of lead nitrate?

31.What type of chemical reaction takes place between sodium hydroxide and hydrochloric acid?

32.On heating KClO₃, which gas is released?

33.Consider the following reaction:
CaO+H2​O→Ca(OH)2​+heat

34.The chemical reaction in which heat is produced along with the product is called —

35.The following chemical reaction is of which type?

4NH3​+5O2​→4NO+6H2​O

36.Which of the following metals will displace iron from ferrous sulfate solution?

37.Which of the following is not a decomposition reaction?

38.Silver chloride is kept in a dark brown bottle because:

39.Which of the following is an endothermic reaction?

40.When water is electrolyzed, the mole ratio of hydrogen and oxygen gases released is:

41.A piece of iron is dipped in an aqueous solution of copper sulfate. After 30 minutes, how will the color of the solution change?

42.When citric acid is added to a purple potassium permanganate (KMnO4KMnO_4KMnO4​) solution, how does the color change?

43.When sulfur dioxide (SO2)gas is passed into an acidic potassium dichromate (K2Cr2O7) solution, what will be the color change?

44. Between which of the following displacement reaction cannot occur?

45.When a magnesium ribbon is burned in the presence of nitrogen gas, which compound is formed?

46.Which of the following metals will displace copper from a copper sulfate (CuSO4CuSO_4CuSO4​) solution?

47.What is the name of the external substance used to prevent fats and oily foods from getting rancid?

48.Which of the following is a combustion reaction?

49.When quick lime (CaO) reacts with water,

50.To preserve fresh oil for a long time, which of the following gases is used?

51.When a light green powdery substance is heated, a gas with a pungent smell is released, and a brown solid remains. What type of reaction is this?

52.When slaked lime (Ca(OH)₂) solution is used for whitewashing walls, the shine of the wall increases. Which substance is responsible for this increase in shine?

53.When molten sodium chloride (NaCl) is electrolyzed, which of the following observations will be noticed?

54.In a test tube, a small amount of barium hydroxide is taken, and a little ammonium chloride is added. The mixture is stirred with a glass rod. Which of the following statements about this reaction is correct?

55.Identify the false statement among the following:

55.A clean aluminum sheet is dipped in an aqueous solution of zinc sulfate. After about 20 minutes, when the aluminum sheet is taken out, a shiny gray layer is deposited on it. What does this indicate?

57.When a copper wire is dipped into a solution of silver nitrate, a shiny layer of silver is deposited on the copper wire. What does this reaction indicate?

58.Which of the following phenomena is related to a chemical reaction?

60.Consider the following statements:

1. Magnesium can burn in the presence of nitrogen gas.
2. Antimony powder can be burned in the presence of chlorine gas.
3. A burning candle goes out when placed in a vessel filled with chlorine gas.

Which of the above statements are correct?

61.Which of the following substances can burn in the presence of CO with the release of heat and light?

62.The chemical reactions that can occur in both directions are called:

63.When a shiny brownish element is heated in air, its color turns black. Which of the following elements is this?

64.Consider the following statements:

1. A chemical reaction in which a reactant exists in more than one oxidation state is called a redox reaction.
2. In the Haber process for the production of ammonia, a redox reaction takes place.

Which of the above statements is/are correct?

65.After a chemical reaction starts, over time:

66.To start a chemical reaction, reactants need to be brought to an active or excited state by supplying extra heat (energy). This energy is called:

67.Which of the following factors does not affect the rate of a chemical reaction?

68.The rate of reaction of a substance:

69.In a chemical equilibrium:

70.When a solid reactant is broken into smaller pieces, the rate of reaction:

71.The rate of many chemical reactions increases or decreases in the presence of some external substance. This external substance is:

72.Catalysts are substances that:

73.In a chemical reaction, the role of a catalyst is to change —

74.Which of the following statements about a catalyst is correct?

1. It increases the rate of the reaction.
2. It increases the activation energy.
3. It decreases the activation energy.
4. It gets consumed in the reaction.

Code:

75.Consider the following statements:

1. When the catalyst, reactants, and products are all in the same physical state, the catalyst is called a homogeneous catalyst.
2. A heterogeneous catalyst is one in which the catalyst and reactants are in different physical states.

Which of the above statements is/are correct?

76.Substances that destroy the activity of a catalyst in chemical reactions are called –

77.The nature of a catalyst poison is –

78.How does a catalyst poison work?

79.What is the role of a positive catalyst in a chemical reaction?

80.When potassium chlorate is heated, it decomposes into potassium chloride and oxygen. When manganese dioxide is added, the reaction becomes faster. The reason is:

81.A negative catalyst is one which—

82.Among the following, which type of elements are the best catalysts?

83.If in a reaction, one of the products itself acts as a catalyst, what is it called?

84. Catalyst Enhancer –

85. A catalyst promoter works by –

86. What is called a biological catalyst?

87. Which of the following statements is correct?

88. Consider the following statements:

1. Enzymes are complex nitrogen-containing inorganic compounds.
2. Enzymes are specific in nature.

Which of the above statements is correct?

89. Which of the following statements is correct?

90. In a molecule AB, if the charge distribution is A⁺ B⁻, then this molecule is –

91. An ionic bond is formed when –

92. An electrovalent (ionic) bond is formed –

93. A covalent bond is formed due to –

94. Consider the following statements:

1. An ionic bond is formed between metal and non-metal atoms.
2. A covalent bond is formed between non-metal atoms.

Which of the above statements is correct?

95. Example of a covalent compound –

96. Example of an ionic compound –

97. The types of bonds present in CuSO₄·5H₂O are –

98. Hydrogen has a tendency to gain one electron to achieve the electronic configuration of helium. This tendency is similar to –

100. A cation is formed when –

99. An atom that gains an electron –

101. The maximum covalency of sulfur is –

102. Which of the following compounds does NOT have an ionic bond?

103. Which of the following is a covalent compound?

104. A compound in which ionic, covalent, and coordinate (dative) bonds are all present –

105. Covalent compounds have low melting and boiling points because –

106. Consider the following statements:

1. Chemical reactions between ionic compounds are slow.
2. Chemical reactions between covalent compounds are fast.

Which of the above statements is/are correct?

107.Which of the following molecules has a covalent bond?

108.The melting and boiling points of ionic compounds are high because –

109.When a chemical bond is formed, what happens?

110.When two atoms of the same element combine, the nature of the bond between them is –

111.Which of the following compounds does not have hydrogen bonding?

Which of the following exhibits hydrogen bonding?

114. What is the reason for the high boiling point of water?

115.Which of the following has a covalent bond?

Hydrogen chloride (HCl) is a gas, but hydrogen fluoride (HF) is a low boiling liquid, because –

Consider the following statements:

1. Breaking chemical bonds is an endothermic reaction.
2. Formation of chemical bonds is an exothermic reaction.

Which of the above statements is/are correct?

119 Molten sodium chloride can conduct electricity because it contains –