alleryStart learning →A liquid turns blue litmus paper red. The liquid is most likely
- An acid solution
- A neutral salt
- A base solution
- An alkali solution
Show answer and solution
Correct answer: A. An acid solution
Acids change blue litmus to red, so the liquid is acidic.
Olympiad (Class 7) Acids, bases and salts — practice questions
Explore 58 free Acids, bases and salts questions in Olympiad (Class 7) Science. Open each question or exercise to read its content, reference answers and available explanation.
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Showing questions 1–30 of 58.
A liquid turns blue litmus paper red. The liquid is most likelyRead the answer and worked solution →Red litmus paper turns blue in a soap solution. Soap solution is thereforeRead the answer and worked solution →Phenolphthalein is added to sodium hydroxide solution. It turnsRead the answer and worked solution →Methyl orange indicator is added to a base. The colour seen isRead the answer and worked solution →The word acid comes from the Latin acidus. What does acidus mean?Read the answer and worked solution →Which pH value could a vinegar solution have?Read the answer and worked solution →A solution has pH 11. It isRead the answer and worked solution →Which feel and taste are typical of bases?Read the answer and worked solution →Which acid in the stomach helps to digest food?Read the answer and worked solution →Vinegar used in kitchens is a dilute solution of which acid?Read the answer and worked solution →Which acid is filled in a car battery?Read the answer and worked solution →Lemons and oranges taste sour mainly due to which acid?Read the answer and worked solution →Which acid is also known as vitamin C?Read the answer and worked solution →Which acid is a component of cola drinks?Read the answer and worked solution →A soft drink fizzes when opened as carbonic acid breaks into water andRead the answer and worked solution →Which base is used as an antacid to cure indigestion?Read the answer and worked solution →Which two products form when an acid reacts with a base?Read the answer and worked solution →Sodium hydroxide solution reacts with hydrochloric acid. Which salt forms?Read the answer and worked solution →Magnesium ribbon is added to dilute sulfuric acid. Which gas bubbles out?Read the answer and worked solution →Which base is used in making soap and paper?Read the answer and worked solution →Which compound sold as washing soda softens hard water?Read the answer and worked solution →Which compound is used as baking soda in cooking?Read the answer and worked solution →Removing rust from metals using an acid is calledRead the answer and worked solution →Which acid is the most widely used acid in industry?Read the answer and worked solution →Nitric acid reacts with ammonia to give which fertilizer?Read the answer and worked solution →Which ion do acids increase in water, as Arrhenius proposed in 1884?Read the answer and worked solution →An Arrhenius base gives which ions in water?Read the answer and worked solution →What is a water-soluble base called?Read the answer and worked solution →Which describes a strong acid in water?Read the answer and worked solution →Acid X dissociates only partly in water while acid Y does so fully. Which is true?Read the answer and worked solution →
Worked practice questions
Red litmus paper turns blue in a soap solution. Soap solution is therefore
- A pure acid
- Acidic
- Basic
- Neutral
Show answer and solution
Correct answer: C. Basic
Only bases turn red litmus blue, which marks the solution as basic.
Phenolphthalein is added to sodium hydroxide solution. It turns
- Yellow
- Orange
- Green
- Pink
Show answer and solution
Correct answer: D. Pink
Phenolphthalein shows a pink colour in basic solutions such as sodium hydroxide.
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