Question

On putting few drops of an unknown liquid on pH strip, the colour of pH strip changed to violet . The liquid taken is likely to be (1) water (2) dilute hydrochloric acid (3) dilute acetic acid (4) dilute sodium hydroxide solution

Answer 1

The liquid is Dilute sodium hydroxide as it is basic in nature with pH 13.

Answer 2

The correct option is 4.

• pH strip change to violet in addition to a strong base.
• It shows the violet colour change in the pH range of 12-14.
• Water is a neutral substance and has a pH of 7.
• Dilute HCl has low pH as it is an acid.
• Dilute acetic acid has low pH as it is an acid.
• Only dilute sodium hydroxide solution has high pH as it is a base and show violet colour in pH paper.