Why is it not correct to identify a colourless solution as acid or base only by looking at it?
Answer and explanation
Correct answer: Many acids and bases can be colourless, so indicators are needed
Colour alone is not a reliable chemical test because many common acids and bases, such as dilute hydrochloric acid and sodium hydroxide solution, are colourless. Their nature must be tested safely with an indicator, pH paper, or a calibrated pH meter. Litmus gives an acid–base indication, while a universal indicator gives an approximate pH range. Therefore A is correct; B and C make false universal claims, and D overstates what appearance can show.
Frequently asked questions
What is the correct answer to this question?
Many acids and bases can be colourless, so indicators are needed
Why is this the correct answer?
Colour alone is not a reliable chemical test because many common acids and bases, such as dilute hydrochloric acid and sodium hydroxide solution, are colourless. Their nature must be tested safely with an indicator, pH paper, or a calibrated pH meter. Litmus gives an acid–base indication, while a universal indicator gives an approximate pH range. Therefore A is correct; B and C make false universal claims, and D overstates what appearance can show.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
