SCIENCE  QUESTIONS FOR COMPETITIVE EXAMS

1. Identify the Excretory organ from the following:

A. Brain

B. Liver

C. Heart

D. Skin

2. Identify the Tribals who are skillful in making jute cloths

A. Chenchu’s

B. Koya’s

C. Bonda’s

D. Gond’s

3. A democratic country is ruled by

A. Kings

B. Representatives elected by the people

C. People elected by representatives

D. Queens

4. The following is not a planet

A. Earth

B. Venus

C. Pluto

D. Neptune

5. Identify the blood cells that are helpful in blood coagulation in our body

A. Red blood cells

B. Black blood cells

C. White blood cells

D. Platelets

6. The following is not an extinct animal

A. Kalivi Kodi

B. Punganuru

C. Battameka pakshi

D. Monkey

7. Fats are more in this food

A. Ragi

B. Fruits

C. Vegetables w

D. Ghee

8. Identify the gas that animals absorb through their lungs from the air

A. Dust

B. Carbon dioxide

C. Oxygen

D. Water vapour

9. The nearest planet to the sun is

A. Venus

B.Earth

C. Mercury

D. Jupiter

10. The air around Earth is called

A. Thermosphere

B. Atmosphere

C. Mesosphere

D. Troposphere

11. A dermatologist is a specialist who deals with this organ

A. Teeth

B. Skin

C. Heart

D. Kidneys

12. Identify the part that is not in the respiratory system

A. Heart

B. Nose

C. Wind pipe

D. Lungs

13. Identify the ‘chemical change ‘from the following

A. Rusting of iron

B. Melting of ice

C. Sugar dissolved in water

D. Boiling of water

14. Match the following table.

I-b, II-d, III-a, IV-c 

15. Identify the correct one regarding forests.

I. Non-renewable natural resources

II. Plays an important role in the maintenance of ecological balance

III. Control soil erosion

IV. Help in causing rain

16. Identify the  correct pair from the following

A. Grapes—Oxalic Acid

B. Butter milk—Oleic Acid

C. Spinach—Ascorbic Acid

D. Tamarind—Tartaric Acid

17. Identify the correct sentence from the following.

A. Hot air is heavier than cold air

B. Air contracts on heating and expands on cooling

C. Uneven heating on the Earth causes wind movements

D. Cooler air moves from a low-pressure area to a high-pressure area

18. The metal that is used in the manufacturing of the filament of an electric heater is

A. Iron

B. Nichrome

C. Copper

D. Tungten

19. The device that is used to measure humidity is

A. Anemometer

B. Hygrometer

C. Pulvinometer

D. Anthrometer

20. The soil with an equal proportion of large and fine particles is

A. Clayey Soil

B. Loam Soil

C. Sandy Soil

D. Rocky Soil

21. Identify the plant with complete flowers

A. Ipomoea

B. Bitter gourd

C. Papaya

D. Cucumber

22. Identify the plant that disperses seeds by water.

A. Milky weed

B. Tridox

C. Lotus

D. Dandelion

23. The process of removing hair or fleece from the body of a sheep is called

A. Scoring

B. Bleaching

C. Spinning

D. Shearing

24. Find out the odd one based on the food component present in it

A. Rice

B. 🥔

C. 🥚

D. Roti

25. The number of images formed when the angle between two plane mirrors is 90

A. 4

B. 3

C. 6

D. 2

26. Which of the following has both translatory and rotatory motions?

A. Motion of the blades of a ceiling fan

B. Motion of a potter’s wheel

C. A bouncing ball

D. A rolling ball 

27. Identify the incorrect sentence from the following.

A. Roughage prevents constipation

B. Carbohydrates are energy-giving nutrients

C. A balanced diet is required only for adults

D. Eating junk food damages the digestive system

28. The following horizon of soil is called topsoil

A. O-Horizon

B. A-Horizon

C. E-Horison

D. R-Horizon

29. The device that works by converting electric energy into mechanical energy

A. Electric bulb

B. Electric heater

C. Iron box

D. Ceiling fan

30. The method of treating the filtered water by adding chlorine tablets

A. Chemical Process

B. Physical Process

C. Biological Process

D. Aeration Process

31. Identify the incorrect pair from the following

A. Bryophyllum-Leaf buds

B. Yeast-Budding

C. Onion-Bulbs

D. Potato-Root buds

32. Identify the correct sentence from the following

A. The image that can be obtained on the screen is called a virtual image

B. There will be a concave mirror behind the bulb of the torchlight

C. Reflection from a rough surface forms a regular reflection

D. Dentists use plane mirrors to observe the backside of our teeth

33. The substance formed when the Magnesium strip/ribbon burns in the presence of Oxygen is

A. Magnesium oxide

B. Magnesium hydroxide

C. Magnesium carbonate

D. Magnesium sulphate

34. The organisms that obtain nutrients from decaying matter are

A. Autotrophs

B. Carnivorous

C. Saprophytes

D. Insectivorous

35. The respiratory organs of the cockroach are

A. Gills

B. Skin

C. Trachea

D. Lungs

36. The gas released when metals like copper and zinc are added to lemon juice is

A. Oxygen

B. Hydrogen

C. Carbon dioxide

D. Nitrogen

37. Which of the following is not a contact force?

A. Pushing a door

B. Peddling a cycle

C. Freely falling fruit from a tree

D.Throwing a ball

38. Statement I: Friction is independent of the area of contact.

Statement II: Friction is dependent on the area of contact.

A. Statement I  only correct

B.Statement II is only correct

C. Statements I and II are both correct

D. Statements I and II are both wrong

39. Sounds do not travel through

A. Solids

B. Vaccums

C. liquids

D.Gasses

40. Thermosetting plastic from the following is

A. Pen refill

B. Cooker Handle

C. Milk product

D. PET Bottle

41. By-product of the coal  from the following is

A. Petroleum

B. Natural gas

C.Paraffin Wax

D. Coaltar

42. The metal does not react with air

A. Iron

B. Aluminium

C.Gold

D. Zinc

43. Which of the following is incorrect concerning the image formed by a plant mirror?

A. Inverted image

B. Lateral inverted image

C. Virtual image

D. The size of the image is equal to the size of the object

44. The property of material to be made into thin wires is called

A. Ductility

B. Sonority

C. Luster

D. Malleability

45. A light ray is incident on a plane mirror. The angle between the incident ray and the reflected ray is 120⁰, then the angle of reflection is

A. 120⁰

B. 60⁰

C. 90⁰

D. 45⁰

46. The dark zone of the candle flame is

A. Hottest part

B. Less heat generated

C. Combustion takes place

D. Combustion does not take place

47. Which of the following can be used as an electrolyte?

A. Distilled water

B. Sugar solution

C. Acidic solution

D. Kerosene

48. The region of the earthquake occurs

A. Mantle

B. Earth crust

C. Inner core of Earth

D. Outer core of Earth

49. The object that revolves around the sun between the orbits of Mars and Jupiter

A. Asteroids

B. Comet

C. Meteor

D. Satellite

50. Species that have vanished from Earth forever are called

A. Eddemic

B. Endangered

C. Extinct

D. Invasive Alien Species

52. Identify the pathogens from the following

A. House fly

B. Bacteria

C. Mosquito

D. Horse

53. Identify the cell that transmits information in the human body

A. Muscle Cell

B. Bone Cell

C. Nerve Cell

D. Blood Cell

54. Identify the food Chain showing the correct sequence of organisms from the following.

A. Plants –> Insects–> Frog–> Snake–> Eagle

B. Plants –> Rat–> Rabbit–> Fox –> Tiger

C. Plants –> Goat –> Deer –> Tiger–> Lion

D. Plants –> Fish –> Crane –> Snake–> Hippopotamus

55. Identify the microorganism present in the rotten coconut

A. Yeast

B. Paramecium

C. Rhizopus

D.Lactobacillus

56. The enrichment of water by nutrients leads to excessive plant growth, which could

A. Biomagnification

B. Bioaccumulation

C. Bioremediation

D. Eutrophication

57. Identify the correct sequence regarding fertilisation from the following.

A. Sperm+ Ovem –> Zygote

B. Zygote –> Feotus –> Embryo

C. Foetus –> Embryo –> Zygote

D. Ovary –> Ovem –> Embryo

58. Identify the element that is not essential for crop plants

A. Nitrogrn

B. Potassium

C. Phosphorous

D. Chromium

59. The flower having only a filament and an anther is called

A. Unisexual flower

B. Bisexual flower

C. Female flower

D. Complete flower

60. Identify the incorrect sentence regarding the uses of microorganisms from the following

A. These are useful in decomposing biological waste material

B.These are helpful in the preparation of antibodies

C. These cause disease

D. These are helpful in the preparation of Idli, Dosa, and Cake

61. Blue revolution means

A.  Cultivating Fish on a large scale

B. honey bees

C. Production of more milk

D. Growing trees

62. Identify the correct option based on the following sentences

I. Antibodies can cure bacterial diseases

II. Vaccines help in curing viral diseases

A. Both sentences are correct

B. Both sentences are in correct

C. Sentence I is correct and II is incorrect

D. Sentence I is incorrect and II is correct

63. When a metal carbonate reacts with dilute hydrochloric acid, the products are:
A) Salt + Water

B) Salt + Carbon dioxide
C) Salt + Carbon dioxide + Water

D) Salt + Oxygen + Water
64. Which gas turns lime water milky?
A) Oxygen

B) Hydrogen

C) Nitrogen

D) Carbon dioxide
65. The chemical equation for the reaction of sodium bicarbonate with HCl is:
A) NaHCO₃ + HCl → NaCl + CO₂ + H₂O

B) NaHCO₃ + HCl → NaCl + H₂
C) NaHCO₃ + HCl → NaOH + CO₂

D) NaHCO₃ + HCl → NaCl + O₂
66. Which of the following turns lime water milky when passed through it?
A) Hydrogen gas

B) Oxygen gas

C) Carbon dioxide gas

D) Nitrogen gas
67. What type of reaction is the reaction of a metal carbonate with acid?
A) Combination

B) Displacement

C) Neutralization

D) Double displacement with gas evolution

68. What is observed when calcium carbonate is treated with dilute HCl?

A) Formation of a precipitate

B) Evolution of a gas with brisk effervescence

C) No reaction

D) Color change

69. Lime water is chemically:

A) CaCO₃

B) CaCl₂

C) Ca(OH)₂

D) CaSO₄

70. Which metal hydrogen carbonate is used in baking and reacts with acid to produce CO₂?

A) Ca(HCO₃)₂

B) NaHCO₃

C) Mg(HCO₃)₂

D) Zn(HCO₃)₂

71. What causes the milkiness in lime water when CO₂ is passed through it?

A) CaCO₃ formation

B) CaCl₂ formation

C) NaCl formation

D) CaSO₄ formation

72. Which of the following will produce carbon dioxide when reacted with dilute acid?

A) Sodium hydroxide

B) Sodium carbonate

C) Zinc

D) Aluminium

73. Which of the following is a natural indicator?

A) Phenolphthalein

B) Methyl orange

C) Litmus

D) None

74. What color does turmeric turn in basic solution?

A) Blue

B) Pink

C) Red

D) Reddish-brown

75. Phenolphthalein is:

A) Natural indicator

B) Synthetic indicator

C) Olfactory indicator

D) None of the above

76. Which one of the following does NOT change color in a neutral solution?

A) Litmus

B) Phenolphthalein

C) Methyl orange

D) All of these

77. Blue litmus paper turns red in:

A) Water

B) Base

C) Acid

D) Salt

78. Which of the following is an olfactory indicator?

A) Litmus

B) Phenolphthalein

C) Onion

D) Methyl orange

79. What happens to the smell of onion in a basic solution?

A) It becomes stronger

B) It turns sour

C) It disappears

D) It remains unchanged

80. In an acidic solution, the smell of vanilla:

A) Disappears

B) Changes to bitter

C) Remains the same

D) Turns foul

81. Which of the following is not an olfactory indicator?

A) Onion

B) Vanilla essence

C) Rose water

D) Clove oil

82. The unique feature of olfactory indicators is:

A) Change in temperature

B) Change in odor

C) Change in shape

D) Change in taste

83. What change is observed when vanilla essence is added to a base?

A) Smell increases

B) Smell disappears

C) Color changes

D) It starts boiling

84. Which of the following pairs are both olfactory indicators?

A) Turmeric and onion

B) Onion and vanilla

C) Vanilla and litmus

D) Phenolphthalein and methyl orange

85. When a metal reacts with dilute hydrochloric acid, the products are:

A) Salt and water

B) Salt and hydrogen gas

C) Salt and oxygen

D) Base and hydrogen gas

86. Which of the following metals will not liberate hydrogen gas on reacting with dilute HCl?

A) Zinc

B) Magnesium

C) Copper

D) Iron

87. Hydrogen gas is confirmed by:

A) Smell test

B) Turning lime water milky

C) Popping sound with a burning matchstick

D) Glowing splint test

88. The balanced chemical equation for the reaction of zinc with dilute hydrochloric acid is:

A) Zn + 2HCl → ZnCl₂ + H₂↑

B) Zn + HCl → ZnHCl

C) Zn + HCl → ZnCl + H

D) Zn + 2HCl → ZnCl + H₂

89. Which of the following is the correct observation when magnesium is added to dilute sulfuric acid?

A) No reaction

B) White precipitate

C) Effervescence and heat released

D) Blue coloration

90. Which of these metals is the least reactive with acids?

A) Zinc

B) Magnesium

C) Copper

D) Iron

91. Which acid-metal reaction produces zinc sulfate and hydrogen gas?

A) Zinc + HCl

B) Zinc + H₂SO₄

C) Zinc + HNO₃

D) Zinc + CH₃COOH

92. Reaction between acids and metals is an example of:

A) Combination reaction

B) Displacement reaction

C) Decomposition reaction

D) Neutralization reaction

93. The ‘pop’ sound in the acid-metal reaction is due to:

A) Evolution of oxygen

B) Reaction with nitrogen

C) Combustion of hydrogen gas

D) Heating of acid

94. When a metal reacts with a base, the products are:

A) Salt and water

B) Salt and oxygen

C) Salt and hydrogen gas

D) Base and hydrogen gas

95. Which of the following metals reacts with sodium hydroxide to produce hydrogen gas?

A) Copper

B) Silver

C) Zinc

D) Gold
96. The gas evolved when a metal reacts with a base is:

A) Oxygen

B) Nitrogen

C) Hydrogen

D) Carbon dioxide

97. The chemical formula of the salt formed when zinc reacts with NaOH is:

A) Zn(OH)₂

B) NaZnO₂

C) ZnNa

D) ZnO

98. The correct equation for reaction between zinc and sodium hydroxide is:

A) Zn + NaOH → ZnNa + H₂

B) Zn + 2NaOH → Na₂ZnO₂ + H₂

C) Zn + NaOH → NaOH + H₂

D) Zn + NaOH → ZnO + Na + H₂
99. Which of the following does not react with sodium hydroxide?

A) Zinc

B) Aluminium

C) Copper

D) Lead

100. What confirms the presence of hydrogen gas in base-metal reactions?

A) Turning lime water milky

B) Glowing splint test

C) Pop sound with a burning matchstick

D) Change in pH

101. Which type of chemical reaction occurs when a base reacts with a metal?
A) Neutralization

B) Combination

C) Decomposition

D) Displacement

102. Which of the following statements is true about the reaction of a base with a metal?

A) All metals react with bases

B) Hydrogen gas is always evolved

C) Zinc reacts with NaOH to form sodium zincate and hydrogen

D) Bases do not react with metals

103. In a neutralisation reaction:

A) Acid and base form gas

B) Acid and base form salt and water
C) Acid and base form metal oxide

D) None of the above

104. Which of the following is a neutralization reaction?
A) Zn + HCl → ZnCl₂ + H₂

B) NaOH + HCl → NaCl + H₂O

C) CuO + HCl → CuCl₂ + H₂O

D) CaCO₃ + HCl → CaCl₂ + CO₂ + H₂O

105. Neutralisation is a reaction between:

A) Acid and metal

B) Base and metal

C) Acid and base

D) Acid and oxide

106. When a metal oxide reacts with an acid, it forms:

A) Salt and water

B) Base and water

C) Salt and hydrogen

D) Oxide and gas
107. Which of the following metal oxides reacts with HCl to form CuCl₂ and H₂O?
A) ZnO

B) CuO

C) Na₂O

D) Al₂O₃
108.  Their reaction can confirm the basic nature of metal oxides:
A) Bases

B) Acids

C) Salts

D) Water

109. Which of the following equations is correct for a metal oxide and an acid reaction?

A) NaOH + HCl → NaCl + H₂O

B) ZnO + H₂SO₄ → ZnSO₄ + H₂

C) CuO + 2HCl → CuCl₂ + H₂O D) Zn + HCl → ZnCl₂ + H₂

110. Metal oxides are generally:

A) Acidic

B) Neutral

C) Basic

D) Amphoteric

111. What is common in all aqueous acid solutions?

A) OH⁻ ions

B) H⁺ ions

C) Na⁺ ions

D) Cl⁻ ions

112. What is common in all aqueous base solutions?

A) CO₃²⁻ ions

B) Cl⁻ ions

C) OH⁻ ions

D) H⁺ ions

113. The acidic and basic nature of a substance is due to:

A) Its smell

B) Presence of ions in the dry state

C) Presence of ions in aqueous solution

D) Its taste

114. In a circuit, the bulb glows when dipped in which of the following?

A) Glucose solution

B) Alcohol solution

C) HCl solution

D) Distilled water

115. Which of the following solutions will not make the bulb glow?

A) Hydrochloric acid

B) Nitric acid

C) Alcohol

D) Sodium hydroxide

116. Glucose and alcohol do not conduct electricity because:

A) They are acidic

B) They do not form ions in solution

C) They are volatile

D) They are dry

117. What is the evidence that HCl and HNO₃ release ions in solution?

A) Color change

B) Release of gas

C) Glowing of the bulb

D) Precipitate formation

118. Which of the following is an electrolyte that can conduct electricity in aqueous form?

A) Alcohol

B) Glucose

C) HNO₃

D) Sugar

119. The glowing of a bulb in an acid or a base solution proves:

A) They are corrosive

B) They are sour or bitter

C) They form ions in water

D) They are colored

120. Which of the following is not an acid or base but a covalent compound?

A) NaOH

B) HCl

C) HNO₃

D) Glucose

121. Which of the following reactions is observed when acid is added to water?

A) Endothermic

B) Combustion

C) Exothermic

D) Displacement

122. Why is acid added to water and not water to acid?

A) To reduce volume

B) To prevent violent splashing

C) To mix it faster

D) To make it weak

123. Which of the following substances releases heat when diluted with water?

A) Glucose

B) Alcohol

C) Hydrochloric acid

D) Salt solution

124. Bulb glows brightly in:

A) Distilled water

B) Glucose solution

C) Dilute HCl

D) Alcohol

125. Which solution allows the bulb to glow due to the presence of ions?

A) Glucose

B) Alcohol

C) HNO₃

D) Sugar

126. Weak acids or bases cause:

A) Bulb to explode

B) No bulb glow

C) Dim bulb glow

D) Loud sound

127. Which of the following is a non-electrolyte?

A) NaOH solution

B) Glucose solution

C) H₂SO₄ solution

D) KOH solution

128. If no light is observed in a bulb experiment, the solution might be:

A) NaOH

B) HCl

C) Glucose

D) KOH

129. Tooth decay begins when the pH of the mouth falls below:

A) 6.5

B) 7

C) 5.5

D) 8

130. The acid present in the stomach is:

A) Acetic acid

B) Hydrochloric acid

C) Nitric acid

D) Citric acid

131. Antacids are used to:

A) Increase the acidity in the stomach

B) Neutralize excess acid

C) Digest protein

D) Absorb nutrients

132. Which of the following is used to treat bee stings?

A) Vinegar

B) Baking soda

C) Lemon juice

D) Soap solution

133. Acid rain is harmful to:

A) Soil

B) Buildings

C) Aquatic life

D) All of these

134. A wasp sting is alkaline in nature. It is treated with:

A) Baking soda

B) Vinegar

C) Toothpaste

D) Soap

135. Which of the following is an antacid?

A) Magnesium hydroxide

B) Sodium hydroxide

C) Hydrochloric acid

D) Calcium carbonate

136. What is the pH of pure water at 25°C?

A) 6

B) 7

C) 8

D) 9

138. Which of the following substances lowers the pH of water bodies during acid rain?

A) SO₂ and NO₂ gases

B) O₂ and CO₂

C) NH₃ and CH₄

D) O₃ and N₂

139. Slaked lime is chemically known as:

A) CaCO₃

B) Ca(OH)₂

C) CaSO₄

D) CaO

140. Which of the following pH values indicates a strong acid?

A) 6

B) 7

C) 4

D) 13

141. To make soil less acidic, a farmer can use:

A) Vinegar

B) Salt

C) Organic matter

D) Quick lime

142. Chemical formula of bleaching powder is:

A) CaCl₂

B) CaOCl₂

C) CaCO₃

D) CaSO₄
143. Baking soda is:

A) Sodium carbonate

B) Sodium bicarbonate
C) Sodium chloride

D) Sodium hydroxide

144. Washing soda is:

A) NaHCO₃

B) Na₂CO₃·10H₂O

C) NaCl

D) NaOH

145. Which of the following is used to make baking powder?

A) Bleaching powder

B) Sodium bicarbonate

C) Plaster of Paris

D) Gypsum

146. Which compound is used to clean water in water treatment plants?

A) Baking soda

B) Washing soda

C) Bleaching powder

D) Plaster of Paris

147. The gas released when baking soda reacts with acid is:

A) O₂

B) CO₂

C) N₂

D) H₂

148. Plaster of Paris is obtained by heating:

A) Limestone

B) Gypsum

C) Marble

D) Soda ash

149. The chemical name of washing soda is:

A) Sodium bicarbonate

B) Sodium carbonate

C) Sodium hydroxide

D) Calcium carbonate

150. The number of water molecules in one molecule of washing soda is:

A) 1

B) 5

C) 7

D) 10

151. Bleaching powder is used for:

A) Softening hard water

B) Disinfecting water

C) Baking

D) Setting fractured bones

152. Plaster of Paris reacts with water to form:

A) CaCO₃

B) CaCl₂

C) CaSO₄·2H₂O

D) Na₂CO₃

153. The pH of sodium bicarbonate is:

A) Strongly acidic

B) Strongly basic

C) Neutral

D) Mildly basic

154. Sodium carbonate is used in:

A) Disinfectants

B) Fire extinguishers

C) Water softening

D) Toothpaste

155. Which compound is not a salt?

A) NaCl

B) NaOH

C) Na₂CO₃

D) NaHCO₃

156. Which compound is used to make school chalks?

A) Baking soda

B) Washing soda

C) POP

D) Bleaching powder

157. Water of crystallization is:

A) Water that is loosely attached

B) Water present in the air

C) Water chemically bound in crystals

D) Water formed by combustion

158. The chemical formula of blue vitriol is:

A) CuSO₄

B) CuSO₄·2H₂O

C) CuSO₄·5H₂O

D) Cu(OH)₂

159. When copper sulfate is heated, it changes from:

A) Blue to green

B) Blue to white

C) White to blue

D) Blue to black

160. How many water molecules are present in gypsum?

A) 1

B) 2

C) 5

D) 10

161. Which salt contains 10 water molecules?

A) Washing soda

B) Baking soda

C) Common salt

D) Plaster of Paris

163. Loss of water of crystallization turns blue copper sulfate into:

A) Blue powder

B) White powder

C) Red powder

D) Green crystals

164. What is the formula of Plaster of Paris?

A) CaSO₄·2H₂O

B) CaSO₄

C) CaSO₄·½H₂O

D) CaCO₃

165. Which of the following loses its water of crystallization on heating?

A) NaCl

B) CaCO₃

C) CuSO₄·5H₂O

D) KCl

166. The blue color of copper sulfate crystals is due to:

A) Oxygen

B) Nitrogen

C) Water of crystallization

D) Hydrogen

167. Anhydrous salts can regain color when exposed to:

A) Alcohol

B) Sunlight

C) Moisture

D) Oxygen