Objective

Question-2. What does the base taste like?

Ans- bitter

Question-3. What do acids and bases do to each other's effect?

Ans- nostalgic (finished)

Question-4. In what form is acid?

Ans- as solid, liquid and gas

Question-5. Into how many classes are acids classified according to their strength?

Ans- Two (strong acid and weak acid)

Question-6. What do all acids have in common?

Ans- hydrogen

Question-7. What does the acid do to blue litmus paper?

Ans- Red

Question-8. What does a base do to red litmus paper?

Ans- Blue

Question-9. What is a litmus letter?

Ans- natural pointer

Question-10. What are the indicators of methyl orange and phenolphthalein?

Ans- synthetic pointer

Question-11. Turmeric, colored petals of flowers, red turnip (beetroot), red cabbage, peduncle and hydrangea indicate which?

Ans- natural pointer

Question-12. By which change do indicators indicate whether a substance is acidic, basic or neutral?

Ans- by color change

Question-13. Substances whose odor changes in acidic or alkaline medium are called?

Ans- odor indicator

Question-14. What is the indicator of Onion, Vanilla, Long oil?

Ans- olfactory (odor) indicator

Question-15. Which of the following is used to find the concentration of hydrogen ion present in a solution?

Ans- of the pH scale

Question-16. What is the value of pH scale between?

Ans- between 0 and 14

Question-17. The lower the pH of a solution is less than 7 then the higher the solution is?

Ans- acidic

Question-18. The higher the concentration of hydrogen ion or hydronium ion in a solution, then what will be the value of its pH?

Ans-

High concentration of hydrogen ion → low pH

Low concentration of hydrogen ion → high value of pH

Question-19. Into how many classes are the bases divided according to their strength?

Ans- Two (strong base and weak base)

Question-20. What is the pH value of an acid?

Ans- less than 7

Question-21. What is the pH value of a base?

Ans- over 7

Question-22. What does an acid give when dissolved in water?

Ans- Hydrogen Ion (H+)

Question-23. What does a base produce when it dissolves in water?

उत्तर- Hydroxide ion (OH‾)

Question-24. How many hydrogen ions are there in pure water?

Ans- very less

Question-25. What is the name of an acid that gives a large number of hydrogen ions (H+) when dissolved in water?

Ans- strong acid

Question-26. What is the name of an acid that gives a small number of hydrogen ions (H) when dissolved in water?

Ans- weak acid

Question-27. What are the bases that give a large number of hydroxides (OH‾) when dissolved in water called?

Ans- strong base

Question-28. What is the natural color of litmus?

Ans- purple

Question-29. Which acid is present in ant sting?

Ans- methanoic acid

Question-30. What is the pH of NaCl (sodium chloride)?

Ans- 7

Question-31. Name the major salt present in sea water?

Ans- Sodium Chloride (NaCl)

Question-32. Name a metal carbonate which is soluble in water?

Ans- sodium carbonate

Question-33. Is aqueous solution of washing soda acidic or alkaline?

Ans- alkaline

Question-34. Name the substance which reacts with chlorine to give bleaching powder?

Ans- slaked lime [Ca(OH)₂]

Question-35. If one solution turns red litmus paper blue, what will be its possible pH?

Ans- 10

Question-36. Which of the following medicines is used to treat indigestion?

Ans- antacid

Question-37. What treatment would you suggest if a person is suffering from acidity?

Ans- Give baking soda solution.

Question-38. What is a substance indicating the presence of an acid and a base called?

Ans- pointer

Question-39. What is an indicator?

Ans- of pigment

Question-40. What is a water soluble base called?

Ans- alkali

Question-41. What happens to electricity in an acidic solution or an alkaline solution in water?

Ans- conductor (driver)

Question-42. What do acids and bases react with each other to form?

Ans- salt and water

Question-43. The strength of which is measured by the pH scale?

Ans- of acid or base

Question-44. What is the value of pH of neutral solution?

Ans- 7

Question-45. How should concentrated acid and concentrated base be mixed in water?

Ans- slowly

Question-46. What is the number of fixed water molecules in a formula unit of a salt called?

Ans- crystallization water

Question-47. Write the chemical formula of plaster of paris?

Ans- CaSo₄•½H₂O

Question-48. What is calcium sulfate dihydrate (CaSo₄•2H₂O) called?

Ans- gypsum

Question-49. Gypsum reacts with water to form what?

Ans- solid material

Question-50. Write the chemical formula of washing soda?

Ans- Na₂Co₃•10H₂O (sodium carbonate decahydrate)

Question-51. Write the chemical formula of baking soda?

Ans- NaHCO₃ (sodium bicarbonate)

Question-52. Which acid is present in lemon and vinegar?

Ans- Lemon → Citric Acid

vinegar → acetic acid

Question-53. What is amal called in English?

Ans- acid

Question-54. Which of the following is an acid?

Ans-

in Citric fruits → Citric acid

in yogurt → lactic acid

in green grapes → basic acid

in the gut → hydrochloric acid

Question-55. Acids and bases react with metals to form what?

Ans- acid and hydrogen gas

Question-56. What does zinc react with sulfuric acid to form?

Ans- hydrogen gas

Question-57. In the active series of metals, metals which are below hydrogen like (Cu, Ag) etc. do not form what on reacting with dilute acids?

Ans- hydrogen gas

Question-58. Metal carbonate and metal hydrogen carbonate react with acids to form what?

Ans- salt, Co₂ and water

Question-59. What happens when calcium carbonate (CaCo₃) is heated?

Ans- CaO (Calcium Oxide)

Question-60. What is formed when calcium oxide (CaO) reacts with water?

Ans- Ca(OH)₂ slaked lime

Question-61. What happens when lead nitrate (PbNO₃) is heated?

Ans- O₂

Question-62. How does the color of phenolphthalein change when a few drops of sodium hydroxide are added?

Ans- pink

Question-63. Acid reacts with metallic oxide to form what?

Ans- salt and water

Question-64. What is the nature of non-metallic oxides?

Ans- acidic

Question-65. Which gas is present in all acids?

Ans- hydrogen

Question-66. Acids dissolve in water to form what?

Ans- of ions

Question-67. What happens to acid and base electricity?

Ans- good conductor

Question-68. Which property does HCl gas not show in the absence of water?

Ans- acidic properties

Question-69. Are all bases soluble in water?

Ans- No

Question-70. Which reaction of dissolving an acid or a base in water is called?

Ans- exothermic

Question-71. What happens to the concentration of hydrogen ions per unit volume when an acid is added to water?

Ans- lack

Question-72. The pH value of a solution is the concentration of hydrogen ions in that solution to the power of?

Ans- to the negative power of 10

Question-73. How does the solution change when the concentration of hydrogen ion (H+) in a solution is increased?

Ans- acidic

Question-74. What are all the alkalis in water?

Ans- solute

Question-75. What are all the bases in water?

Ans- insoluble (does not dissolve in water)

Question-76. What is the value of pH of our body?

Ans- pH between 7.0 to 7.8

Question-77. Which acid is formed in higher concentration in the stomach of dog?

Ans- HCl (Hydrochloric Acid)

Question-78. Which acid is present in ant or bee sting?

Ans- methanoic acid

Question-79. Which of the following is an acid?

Ans-

• tamarind → tartaric acid

• Guava, Tomato → oxalic acid

• Apple → basic acid

• Onion, Amla → ascorbic acid

• fat → stearic acid

• butter → butyric acid

Question-80. What are the melting and boiling points of salts?

Ans- high

Question-81. Which ion is present in the salt?

Ans- positive and negative ion

Question-82. Which compound is called a salt?

Ans- ionic

Question-83. What is present as an impurity in common salt?

Ans- Magnesium Chloride (MgCl₂)

Question-84. What is the chemical formula of bleaching powder?

Ans- CaOCl₂ (Calcium Oxychloride)

Question-85. What is chlorine gas used for?

Ans- in bleaching powder

Question-86. Which is used in making cakes and bread?

Ans- of baking soda

Question-87. What is used to purify petroleum?

Ans- Washing Soda (Na₂Co₃•10H₂O)

Question-88. Write the chemical formula of gypsum?

Ans- CaSo₄•2H₂O (calcium sulfate dihydrate)

Question-89. What is the atomic number of iron?

Ans- 26

Question-90. A solution turns red litmus paper blue, its pH will be

Ans- 5

Question-91. An element reacts with oxygen to form a compound with a high melting point. This compound is soluble in water. Which element is this?

Ans- Iron (Fe)

Question-92. How many oxygen atoms are there in one molecule of ozone?

Ans- 3

Question-93. Write the name of an inert gas.

Ans- Helium (He)

Question-94. Oxygen is released during photosynthesis?

Ans- from glucose

Question-95. Where is magnesium found?

Ans- in chlorophyll

Question-96. Litmus solution is a violet dye, which is extracted from

Ans- from lichen

Question-97. Which of the following is a heterogeneous compound?

Ans- (d) plaster of Paris

Question-98. How many bonds are found between two oxygen atoms?

Ans- two

Question-99. What is the chemical formula of blue thorn (tutia)?

Ans- CuSO₄•5H₂O

Question-100. Which of the following is a salt?

Ans- (c) K₂SO₄

Question-101. How does the color of the solute change when a solution of methyl orange is added to an aqueous solution of sodium carbonate?

Ans- yellow

Question-102. What is the color of sodium in flame test?

Ans- yellow

Question-103. What is the molecular formula of sodium carbonate?

Ans- Na₂Co₃

Question-104. Which of the following is an ionic compound?

Ans- (c) CaCl₂

Question-105. What is the pH of pure water?

Ans- 7

Question-106. The presence of CO₂ gas in the atmosphere is?

Ans- 0.03%

Question-107. Oxidation is the process in which

Ans- oxygen uptake

Question-108. In electrolysis the electron is liberated?

Ans- at the anode

Question-109. Which is the most reactive metal in the activity series?

Ans- Na (sodium)

Question-110. What is the atomic number of calcium?

Ans- 20

Question-111. What is the chemical formula of chalk?

Ans- MgCO₃

Question-112. Which of the following is a strong acid?

Ans- H₂SO₄

Question-113. Which solution is used to whiten the walls?

Ans- Ca(OH)₂ (calcium hydroxide)

Question-114. Which reaction is Na₂So₄ + BaCl₂ → BaSo₄ + 2NaCl?

Ans- double displacement reaction

Question-115. Which of the following is slaked lime?

Ans- Ca(OH)₂

Question-116. The pH of the aqueous solution of salt Na₂Co₃ is.

Ans- 7

Question-117. Plaster of Paris is formed on heating which chemical compound?

Ans- to gypsum

Question-118. Which of the following ions can turn red litmus paper solution blue?

Ans- OH‾

Question-119. Which is the natural source of oxalic acid?

Ans- tomato

Question-120. Which of the following is most reactive?

Ans- K (potassium)

Question-121. What is the flame of fire on burning a magnesium ribbon (lace)?

Ans- White

Question-122. How many oxygen atoms are in one molecule of glucose?

Ans- 6

Question-123. Which of the following gas turns lime water milky?

Ans- CO₂ (carbon dioxide)

Question-124. Which gas is released when zinc and sulfuric acid react?

Ans- H₂ (hydrogen)

Question-125. What is the atomic number of carbon?

Ans- 6

Question-126. How is toothpaste?

Ans- alkaline

Question-127. What causes acid rain?

Ans- SO₂

Question-128. What is the hardest part of our teeth called?

Ans- enamel

Question-129. Which acid helps in digestion of food?

Ans- HCl (hydrochloric acid)