Which of the following substances does not change the colour of either red or blue litmus paper in an aqueous solution?
Answer and explanation
Correct answer: Sodium chloride
The governing idea is the litmus test for acidic, basic and neutral solutions. An aqueous solution of sodium chloride, formed from a strong acid and a strong base, is generally neutral and therefore does not change either red or blue litmus. Hydrochloric acid turns blue litmus red, whereas sodium hydroxide and calcium hydroxide turn red litmus blue. Hence, option C is correct.
Frequently asked questions
What is the correct answer to this question?
Sodium chloride
Why is this the correct answer?
The governing idea is the litmus test for acidic, basic and neutral solutions. An aqueous solution of sodium chloride, formed from a strong acid and a strong base, is generally neutral and therefore does not change either red or blue litmus. Hydrochloric acid turns blue litmus red, whereas sodium hydroxide and calcium hydroxide turn red litmus blue. Hence, option C is correct.
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.
