sour taste pH equal to 6 turns litmus paper blue forms bubbles with limestone
I gave my students this multiple choice question: Common soaps are often basic. Which of these is a property of a chemical base?

Only one answer is correct among these 4 choices:
- sour taste
- pH equal to 6
- turns litmus paper blue
- forms bubbles with limestone

Could you tell me which one is correct?

turns litmus paper blue