What change occurs when red litmus is added to a sodium hydroxide solution?
Answer and explanation
Correct answer: Red litmus turns blue
Sodium hydroxide dissolves in water to give a strongly basic solution containing hydroxide ions. Bases change the indicator litmus from red to blue, so the red litmus paper becomes blue when it contacts sodium hydroxide solution. The change is an indicator response, not a gas-producing reaction; bubbles are unnecessary. A base does not normally make red litmus colorless or green. Thus option A is the only correct observation.
Frequently asked questions
What is the correct answer to this question?
Red litmus turns blue
Why is this the correct answer?
Sodium hydroxide dissolves in water to give a strongly basic solution containing hydroxide ions. Bases change the indicator litmus from red to blue, so the red litmus paper becomes blue when it contacts sodium hydroxide solution. The change is an indicator response, not a gas-producing reaction; bubbles are unnecessary. A base does not normally make red litmus colorless or green. Thus option A is the only correct observation.
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.
