Question

A scientist experiments ima unknown solution. She notices that when a base, sodium hydroxide, is added to the solution, it forms a salt water. What can she infer from this observation?

(A) the unknown solution has a pH of 2.
(B) the unknown solution is acidic.
(C) the unknown solution contains oxygen.
(D) the unknown solution contains hydroxide ions.

Answer 1

the unknown solution is acidic

Answer 2

Answer:

(B) the unknown solution is acidic.

Explanation:

Hello,

In this case, as the unknown solution reacts with sodium hydroxide forming a salt water, one infers that the unknown solution is acidic since all the acids which react with bases form salts and water based on the shown below widespread chemical reaction:

$Acid+Base-->Salt+Water$

Which is a neutralization chemical reaction. It is clear that acidic solutions have pH lower than 7 but it is not enough to substantiate the unknown solution formed the salt after the addition of the base. However, the acid could have oxygen but it is not enough to justify the formation of a salt. Finally, it is impossible for the unknown solution to have hydroxide ions since a neutralization was carried out.

Best regards.