Which of the following best defines an acid?
a) an acid has a ph of 7.
b) an acid has hydroxide ions.
c) an acid has fewer positive ions in solution.
d) an acid has more hydrogen ions in solution.

Option D

A solution is said to be acidic if it gives hydrogen ions in the aqueous solution. In pH meter, acids ranges from 0 to below 7, at 7 solution becomes neutral and above 7 it becomes basic.

An acid can not have a pH of 7 because it is for neutral solutions. An acid does not have hydroxide ions because this is base which gives hydroxide ions in the aqueous solution. A solution with any positive ion can not be acidic, it is acidic in the presence of hydrogen or hydronium ion only.

Thus, option D is correct: an acid has more hydrogen ions in the solution.

b

explanation:

mitosis