Sorry that is Incorrect
The correct answer is: Use universal indicator, if the solution turns red, orange or yellow then it is an acid. All of the answer choices are incorrect here is why:
- Use universal indicator, if the solution turns red, orange or yellow then it is an acid.
- Use a red litmus paper, if the paper turns blue then it is an acid.--> This would demonstrate a base because blue when using litmus paper demonstrates a base, not an acid. An acid's litmus paper color is red.--> This is correct
- Use a blue litmus paper, if the paper stays blue then it is an acid.--> This would demonstrate a base because blue when using litmus paper demonstrates a base, not an acid. An acid's litmus paper color is red.
- Use the pH strips, if the strips indicate that the pH is an 8-14 then it is an acid. --> This is the opposite of the truth, acids have a pH of 0-6, bases have a pH of 8-14.