Asubstance is tested with litmus paper. the blue litmus paper remains blue while the red litmus paper remains red. what can you conclude about the substance?

the substance is a base.

the substance is neutral; it is neither an acid nor a base.

the substance could be either an acid or a base.

none of the above; it is impossible for both red and blue litmus paper to remain unchanged.

Litmus paper is used to determine the pH of a solution. When blue litmus paper is exposed to acidic conditions the paper turns red. In the other hand under basic conditions or when exposed to conditions, it turns blue. When exposed to neutral solutions it turns purple. In the other hand, red litmus paper is used to determine if something is a base. When it is exposed to alkaline solutions it turns blue. Since there is no change in the blue litmus paper we can say the solution or substance is basic or it is a base, and since there was a change in color with the red litmus paper that conclusion is correct.