Question

A student had a sample of pure water, and added an unknown substance to it. the student noticed that the hydroxide ion concentration in the solution increased as the substance was added. what is true about this newly formed solution?

Answer 1

The newly formed solution is basic. It's a base. 

Answer 2

The question is incomplete, here is the complete question.

A student had a sample of pure water, and added an unknown substance to it. The student notice that the hydroxide ion concentration in the solution increased as the substance was added. What is true about this newly formed solution?

A. It is Basic

B. It is Acidic

C. It is a buffer

D. It has a pH of 7

Answer: The newly formed solution is basic.

Explanation:

pH is defined as the negative logarithm of hydrogen ion concentration present in the solution.

• If the solution has high hydrogen ion concentration, then the pH will be low and the solution will be acidic. The pH range of acidic solution is 0 to 6.9
• If the solution has low hydrogen ion concentration, then the pH will be high and the solution will be basic. The pH range of basic solution is 7.1 to 14
• The solution having pH equal to 7 is termed as neutral solution.

We are given:

The concentration of hydroxide ion is increased when an unknown substance is added to water. This means that, concentration of hydrogen ion is less in the solution.

Hence, the newly formed solution is basic in nature.