An oxide is acidic and has a pungent odour. It could be
  • sulphur dioxide
  • carbon dioxide
  • sodium oxide
  • nitrogen dioxide
Out of these gases which one is used in fire extinguishers
  • CO
  • SO
  • NO
  • H
The correct way of making a solution of acid in water is to
  • add water to acid
  • add acid to water
  • mix acid and water simultaneously
  • add water to acid in a shallow container
Products of a neutralisation reaction are always:
  • an acid and a base
  • an acid and a salt
  • a salt and water
  • a salt and a base
Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed.
  • Yellow in both acid and base
  • Yellow in acid and red in base
  • Pink in acid and yellow in base
  • Red in acid and blue in base
Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are:
  • red and blue
  • blue and red
  • pink and colourless
  • colourless and pink
When the soil is too basic, plants do not grow well in it. To improve its quality what must be added to the soil?
  • Organic matter
  • Quick lime
  • Slaked lime
  • Calamine solution
Which of the following set of substances contain acids?
  • Grapes, lime water
  • Vinegar, soap
  • Curd, milk of magnesia
  • Curd, vinegar
On adding phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution?
  • Basic
  • Either acidic or basic
  • Either acidic or neutral
  • Either basic or neutral
Which of the following is an acid-base indicator?
  • Vinegar
  • Lime water
  • Turmeric
  • Baking soda
What color does red litmus paper turn when dipped in a basic solution?
  • Red
  • Blue
  • Green
  • Yellow
Which of the following is an example of an acid?
  • Baking soda
  • Lime water
  • Vinegar
  • Soap solution
What is the pH value of a neutral substance?
  • 0
  • 7
  • 14
  • 10
Which of the following substances is a base?
  • Lemon juice
  • Hydrochloric acid
  • Baking soda
  • Orange juice
What does litmus paper do when it comes in contact with an acidic solution?
  • Blue litmus turns red
  • Red litmus turns blue
  • Blue litmus turns green
  • Red litmus turns yellow
A student has a solution with a pH of 3. Which of the following best describes this solution?
  • Strongly basic
  • Neutral
  • Strongly acidic
  • Weakly basic
When an acid and a base are mixed together, which products are formed during neutralization?
  • Only water
  • Only salt
  • Salt and water
  • Acid and oxygen
A solution has a pH of 11. How would litmus paper react when placed in this solution?
  • Red litmus turns blue, indicating a base
  • Blue litmus turns red, indicating an acid
  • No change in litmus color
  • Red litmus turns green, indicating a neutral solution
A farmer notices that his crops are not growing well because the soil is too acidic. Which of the following actions should he take to neutralize the soil, and why?
  • Add more acid to the soil to balance the pH
  • Add lime (a base) to the soil to raise the pH and neutralize the acidity
  • Add vinegar to the soil to lower the pH further
  • Leave the soil as it is since pH does not affect plant growth
A student tests four unknown solutions using litmus paper and records the following results: Solution A turns blue litmus red, Solution B shows no change in either litmus, Solution C turns red litmus blue, and Solution D turns blue litmus red. Which conclusion is most accurate?
  • Solutions A and D are bases, Solution B is neutral, and Solution C is an acid
  • Solutions A and D are acids, Solution B is neutral, and Solution C is a base
  • All four solutions are acids
  • Solutions A and C are neutral, while B and D are acids
What color does turmeric turn in an acidic solution?
  • Blue
  • Yellow
  • Green
  • Red
What is the nature of common salt?
  • Basic
  • Acidic
  • Neutral
  • Alkaline
What do neutralization reactions produce?
  • A base and water
  • An acid and a salt
  • A salt and water
  • An acid and a base
What acid is found in the sting of an ant?
  • Acetic acid
  • Formic acid
  • Citric acid
  • Lactic acid
Which of the following is a natural acid-base indicator?
  • Turmeric
  • Baking soda
  • Vinegar
  • Lime water
What is the effect of lemon juice on litmus paper?
  • Turns it blue
  • Turns it green
  • No effect
  • Turns it red
What color does red litmus paper turn in a basic solution?
  • Blue
  • Red
  • Green
  • Yellow
Which of the following is an example of a neutral substance?
  • Vinegar
  • Lemon juice
  • Baking soda
  • Sugar
What is the primary taste of acids?
  • Sweet
  • Sour
  • Bitter
  • Salty
What is the reaction called when an acid and a base react?
  • Synthesis
  • Neutralization
  • Combustion
  • Decomposition
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