Question

Select all that apply.

Which of the following are good ways to test whether a solution is an acid or a base?
tasting it
litmus paper
phenolphthalein
touching it

Answer 1

Tasting it and touching it are both potentially dangerous for a start haha. SO DONT DO THOSE ONES.

Litmus paper is a good choice because its colour changes based on the presence of an acid or base.
Phenolphthalein is an acid-base indicator and does a similar thing to litmus.

Litmus paper and phenolphthalein are the right choices

Answer 2

Answer : The correct options are, litmus paper and phenolphthalein.

Explanation :

Acid : It is a substance that has ability of donating proton or hydrogen ion,
`H^+`.

The properties of an acid are :

Acids are sour in taste.

The texture of an acid solution is sticky.

It changes the color of the litmus paper to red.

Base : It is a substance that has ability of donating hydroxide ion,
`OH^-`.

The properties of an base are :

Base are bitter in taste.

The texture of an base solution is slippery.

It changes the color of the litmus paper to blue.

Indicators : It is a substance that gives the visible sign by the color change of the chemical species like an acid or a base.

Litmus paper : It turns red when it is added to a strong acid, it turns blue or purple when it is added to a strong base and it turns a yellowish-green when it is added to a neutral solution.

Phenolphthalein : It is also used as an indicator in acid–base titrations. It turns colorless in acidic solutions and pink in basic solutions.

Thus, there are two good ways to test whether a solution is an acid or a base which are litmus paper and phenolphthalein.