📘 Study MCQs
Q1. A student tests aerated water with litmus paper. What change will he observe on the blue litmus paper?
A. Turns green
B. Turns red
C. No change
D. Turns blue
B. Turns redAerated water contains dissolved carbon dioxide which forms carbonic acid (H₂CO₃), an acidic solution that turns blue litmus paper red.
Q2. Aerated water is tested with both red and blue litmus papers. What is the correct observation?
A. Red litmus turns blue, blue litmus turns red
B. Both litmus papers turn green
C. Red litmus shows no change, blue litmus turns red
D. Red litmus turns blue, blue litmus shows no change
C. Red litmus shows no change, blue litmus turns redSince aerated water is acidic, it has no effect on red litmus but turns blue litmus red.
Q3. What can be inferred about the nature of aerated water based on its effect on litmus paper?
A. It is basic
B. It is acidic
C. It is neutral
D. It is salty
B. It is acidicThe characteristic of turning blue litmus red without affecting red litmus confirms the solution is acidic.
Q4. Common salt solution is tested with litmus paper. What will be the result on blue litmus paper?
A. Turns red
B. Turns blue
C. Turns green
D. No change
D. No changeCommon salt (sodium chloride) solution is neutral, so it does not change the color of either red or blue litmus paper.
Q5. A student dips both red and blue litmus papers in a beaker containing common salt solution. What will he observe?
A. Red litmus turns blue, blue litmus turns red
B. Both litmus papers turn green
C. Both litmus papers show no change
D. Red litmus turns blue, blue litmus shows no change
C. Both litmus papers show no changeNeutral solutions like salt solution have no effect on the color of litmus paper.
Q6. What is the nature of common salt solution as indicated by the litmus test?
A. Acidic
B. Basic
C. Neutral
D. Slightly sour
C. NeutralThe absence of any color change with both red and blue litmus indicates a neutral solution.
Q7. Shampoo solution is tested with red litmus paper. What change will be observed?
A. No change
B. Turns blue
C. Turns red
D. Turns green
B. Turns blueShampoo is generally basic, so it turns red litmus paper blue.
Q8. A student tests shampoo solution with both red and blue litmus papers. What will be his observation?
A. Red litmus turns blue, blue litmus shows no change
B. Red litmus shows no change, blue litmus turns red
C. Both litmus papers turn green
D. Both litmus papers show no change
A. Red litmus turns blue, blue litmus shows no changeBasic solutions turn red litmus blue but have no effect on blue litmus paper.
Q9. Based on the litmus test, what can be inferred about the nature of shampoo solution?
A. It is acidic
B. It is neutral
C. It is basic
D. It is salty
C. It is basicThe ability to turn red litmus blue confirms the basic nature of shampoo solution.
Q10. Baking soda solution is tested with blue litmus paper. What change will occur?
A. Turns red
B. Turns green
C. No change
D. Turns yellow
C. No changeBaking soda (sodium bicarbonate) is basic, so it does not affect blue litmus but turns red litmus blue.
Q11. A student places a drop of baking soda solution on red litmus paper. What will he observe?
A. The red litmus paper turns blue
B. The red litmus paper turns green
C. The red litmus paper shows no change
D. The red litmus paper turns yellow
A. The red litmus paper turns blueBasic baking soda solution turns red litmus paper blue.
Q12. What is the nature of baking soda solution as shown by the litmus test?
A. Acidic
B. Neutral
C. Basic
D. Sour
C. BasicThe solution turns red litmus blue and has no effect on blue litmus, confirming it is basic.
Q13. Lemon juice is tested with red litmus paper. What will be the result?
A. Turns blue
B. Turns green
C. No change
D. Turns black
C. No changeLemon juice is acidic, so it does not affect red litmus but turns blue litmus red.
Q14. A student tests lemon juice with blue litmus paper. What change will he observe?
A. No change
B. Turns blue
C. Turns red
D. Turns green
C. Turns redLemon juice contains citric acid, which turns blue litmus paper red.
Q15. What inference can be drawn from the litmus test on lemon juice?
A. It is basic
B. It is neutral
C. It is acidic
D. It is soapy
C. It is acidicThe effect of turning blue litmus red without affecting red litmus indicates the solution is acidic.
Q16. Hydrochloric acid solution is a strong mineral acid. What will be its effect on blue litmus paper?
A. No change
B. Turns blue
C. Turns green
D. Turns red
D. Turns redHydrochloric acid is acidic and turns blue litmus paper red.
Q17. A student tests hydrochloric acid with both red and blue litmus papers. What will he observe?
A. Red litmus turns blue, blue litmus shows no change
B. Both litmus papers turn green
C. Red litmus shows no change, blue litmus turns red
D. Both litmus papers show no change
C. Red litmus shows no change, blue litmus turns redAcids do not affect red litmus but turn blue litmus red.
Q18. Based on the litmus test, what is the nature of hydrochloric acid solution?
A. Basic
B. Neutral
C. Acidic
D. Salty
C. AcidicThe characteristic of turning blue litmus red confirms the solution is acidic.
Q19. Nitric acid is another strong mineral acid. What will be its effect on red litmus paper?
A. Turns blue
B. Turns green
C. No change
D. Turns black
C. No changeAcids do not change the color of red litmus paper.
Q20. A student performs a litmus test on nitric acid solution. What will he observe on the blue litmus paper?
A. It turns red
B. It turns blue
C. It turns green
D. No change
A. It turns redNitric acid is acidic and turns blue litmus paper red.
Q21. What inference can be made about nitric acid from the litmus paper test?
A. It is basic
B. It is neutral
C. It is acidic
D. It is soapy
C. It is acidicThe ability to turn blue litmus red while having no effect on red litmus confirms it is acidic.
Q22. Washing soda solution is commonly used as a cleaning agent. What will be its effect on red litmus paper?
A. No change
B. Turns blue
C. Turns red
D. Turns green
B. Turns blueWashing soda (sodium carbonate) is basic and turns red litmus blue.
Q23. A student tests washing soda solution with both red and blue litmus papers. What will he observe?
A. Red litmus turns blue, blue litmus shows no change
B. Red litmus shows no change, blue litmus turns red
C. Both litmus papers turn green
D. Both litmus papers show no change
A. Red litmus turns blue, blue litmus shows no changeBasic solutions like washing soda turn red litmus blue but do not affect blue litmus.
Q24. Based on the litmus test, what is the nature of washing soda solution?
A. Acidic
B. Neutral
C. Basic
D. Sour
C. BasicThe solution turns red litmus blue, confirming it is basic.
Q25. Limewater is used to test for carbon dioxide gas. What will be its effect on blue litmus paper?
A. Turns red
B. No change
C. Turns blue
D. Turns green
B. No changeLimewater (calcium hydroxide) is basic, so it does not affect blue litmus.
Q26. A student dips red litmus paper into a beaker of limewater. What will he observe?
A. The red litmus paper turns blue
B. The red litmus paper turns green
C. The red litmus paper shows no change
D. The red litmus paper turns yellow
A. The red litmus paper turns blueLimewater is basic, so it turns red litmus paper blue.
Q27. What can be inferred about the nature of limewater from its effect on litmus paper?
A. It is acidic
B. It is neutral
C. It is basic
D. It is sour
C. It is basicThe ability to turn red litmus blue confirms limewater is basic.
Q28. Which of the following solutions will turn blue litmus paper red?
A. Soap solution
B. Limewater
C. Lemon juice
D. Baking soda solution
C. Lemon juiceLemon juice is acidic and turns blue litmus red; soap, limewater, and baking soda are basic.
Q29. Which of the following solutions will turn red litmus paper blue?
A. Vinegar
B. Lemon juice
C. Aerated water
D. Shampoo solution
D. Shampoo solutionShampoo is basic and turns red litmus blue; vinegar, lemon juice, and aerated water are acidic.
Q30. A solution has no effect on either red or blue litmus paper. Which of the following could it be?
A. Lemon juice
B. Common salt solution
C. Washing soda solution
D. Vinegar
B. Common salt solutionCommon salt solution is neutral, so it does not affect either red or blue litmus paper.
Q31. Four solutions are tested with litmus paper. Which one is most likely to be aerated water?
A. Turns red litmus blue, no change on blue litmus
B. Turns blue litmus red, no change on red litmus
C. No change on either litmus
D. Turns both litmus papers green
B. Turns blue litmus red, no change on red litmusAerated water is acidic, so it turns blue litmus red but does not affect red litmus.
Q32. Four solutions are tested with litmus paper. Which one is most likely to be shampoo solution?
A. Turns blue litmus red, no change on red litmus
B. Turns red litmus blue, no change on blue litmus
C. No change on either litmus
D. Turns both litmus papers red
B. Turns red litmus blue, no change on blue litmusShampoo is basic, so it turns red litmus blue but does not affect blue litmus.
Q33. A liquid ‘X’ is tested with litmus paper. Red litmus turns blue, but blue litmus shows no change. What is the nature of liquid ‘X’?
A. Acidic
B. Basic
C. Neutral
D. Sour
B. BasicTurning red litmus blue while having no effect on blue litmus is characteristic of a basic solution.
Q34. A liquid ‘Y’ is tested with litmus paper. Blue litmus turns red, but red litmus shows no change. What is the nature of liquid ‘Y’?
A. Basic
B. Neutral
C. Acidic
D. Soapy
C. AcidicTurning blue litmus red without affecting red litmus is characteristic of an acidic solution.
Q35. A liquid ‘Z’ is tested with litmus paper and shows no change on either red or blue litmus. What is the nature of liquid ‘Z’?
A. Acidic
B. Basic
C. Neutral
D. Can be acidic or basic
C. NeutralOnly neutral solutions have no effect on the color of either red or blue litmus paper.
Q36. Which of the following is a pair of acidic solutions based on their effect on litmus?
A. Limewater and soap solution
B. Aerated water and lemon juice
C. Baking soda and washing soda
D. Shampoo and common salt
B. Aerated water and lemon juiceBoth aerated water (carbonic acid) and lemon juice (citric acid) are acidic and turn blue litmus red.
Q37. Which of the following is a pair of basic solutions based on their effect on litmus?
A. Vinegar and lemon juice
B. Aerated water and hydrochloric acid
C. Shampoo and limewater
D. Common salt and sugar solution
C. Shampoo and limewaterBoth shampoo and limewater are basic, turning red litmus blue.
Q38. A student has four unlabeled beakers containing aerated water, common salt solution, shampoo, and lemon juice. How can he identify the beaker with common salt solution using only litmus paper?
A. It will turn red litmus blue
B. It will turn blue litmus red
C. It will turn both litmus papers green
D. It will not change the color of either litmus paper
D. It will not change the color of either litmus paperOnly common salt solution is neutral; the other three are either acidic or basic and will change the color of one litmus paper.
Q39. A student finds that a solution turns blue litmus red. Which of the following could the solution NOT be?
A. Lemon juice
B. Vinegar
C. Limewater
D. Hydrochloric acid
C. LimewaterLimewater is basic and turns red litmus blue, not blue litmus red.
Q40. A student finds that a solution turns red litmus blue. Which of the following could the solution NOT be?
A. Soap solution
B. Washing soda solution
C. Baking soda solution
D. Aerated water
D. Aerated waterAerated water is acidic and turns blue litmus red, not red litmus blue.
Q41. You are given three solutions: P, Q, and R. P turns blue litmus red. Q turns red litmus blue. R shows no change on either litmus. Which option correctly identifies P, Q, and R?
A. P-Base, Q-Acid, R-Neutral
B. P-Acid, Q-Base, R-Neutral
C. P-Neutral, Q-Acid, R-Base
D. P-Acid, Q-Neutral, R-Base
B. P-Acid, Q-Base, R-NeutralP turning blue litmus red indicates it is acidic; Q turning red litmus blue indicates it is basic; R showing no change indicates it is neutral.
Q42. Which of the following statements about nitric acid is correct based on its litmus test?
A. It turns red litmus blue
B. It has no effect on blue litmus
C. It turns blue litmus red
D. It turns both litmus papers red
C. It turns blue litmus redNitric acid is acidic, so it turns blue litmus red but does not affect red litmus.
Q43. Which of the following statements about washing soda solution is correct based on its litmus test?
A. It is acidic and turns blue litmus red
B. It is basic and turns red litmus blue
C. It is neutral and has no effect on litmus
D. It turns both litmus papers blue
B. It is basic and turns red litmus blueWashing soda (sodium carbonate) is basic and turns red litmus paper blue.
Q44. If you accidentally mix an acid and a base, the resulting solution might show what litmus test result?
A. It will definitely turn blue litmus red
B. It will definitely turn red litmus blue
C. It might show no change on either litmus if they exactly neutralize each other
D. It will turn both litmus papers green
C. It might show no change on either litmus if they exactly neutralize each otherWhen an acid and base are mixed in exact proportions, they neutralize to form a neutral salt solution, which does not affect litmus paper.
Q45. Hydrochloric acid and nitric acid are both strong acids. How will their effect on litmus paper compare?
A. HCl will turn blue litmus red, but HNO₃ will turn it blue
B. HCl will turn red litmus blue, but HNO₃ will turn it red
C. Both will have the same effect: turn blue litmus red
D. Both will have no effect on litmus paper
C. Both will have the same effect: turn blue litmus redAll acids, whether strong or weak, have the same effect on litmus paper—they turn blue litmus red without affecting red litmus.
Q46. Baking soda solution and washing soda solution are both basic. How will their effect on red litmus paper compare?
A. Baking soda will turn it blue, but washing soda will turn it red
B. Both will turn red litmus paper blue
C. Baking soda will have no effect, but washing soda will turn it blue
D. Both will have no effect on red litmus
B. Both will turn red litmus paper blueAll basic solutions turn red litmus paper blue, regardless of their specific composition.
Q47. A solution is known to be either limewater or lemon juice. A single drop on red litmus paper will help identify it. How?
A. If it turns red litmus blue, it is lemon juice
B. If it turns red litmus blue, it is limewater
C. If it turns red litmus green, it is limewater
D. If it has no effect, it is limewater
B. If it turns red litmus blue, it is limewaterLimewater (basic) turns red litmus blue; lemon juice (acidic) does not affect red litmus.
Q48. A solution is known to be either aerated water or common salt solution. Testing it with blue litmus paper will reveal its identity. How?
A. If it turns blue litmus red, it is common salt solution
B. If it turns blue litmus red, it is aerated water
C. If it turns blue litmus blue, it is aerated water
D. If it has no effect, it is aerated water
B. If it turns blue litmus red, it is aerated waterAerated water (acidic) turns blue litmus red; common salt solution (neutral) has no effect.
Q49. A teacher showed that shampoos are generally basic. If a particular brand of shampoo were acidic, how would its litmus test result differ?
A. It would turn red litmus blue instead of having no effect
B. It would turn blue litmus red instead of having no effect
C. It would have no effect on red litmus, which it should
D. It would turn both litmus papers red
B. It would turn blue litmus red instead of having no effectBasic shampoos have no effect on blue litmus; if acidic, they would turn blue litmus red.
Q50. Based on the provided data, which of the following conclusions is correct?
A. Only mineral acids turn blue litmus red
B. Substances that turn red litmus blue are all soaps
C. A substance that does not change red litmus could be acidic or neutral
D. Baking soda and washing soda have different effects on red litmus
C. A substance that does not change red litmus could be acidic or neutralAcids have no effect on red litmus, and neutral solutions also have no effect on red litmus. Therefore, a substance that does not change red litmus could be either acidic or neutral.