Question

part d when comparing an acid and a base, which statement is true? an acid has a lower concentration of hydrogen ions and a lower ph than a base. an acid has a higher concentration of hydrogen ions and a lower ph than a base. an acid has a higher concentration of hydrogen ions and a higher ph than a base. neither the hydrogen ion concentration nor the ph has anything to do with whether the substance is an acid or a base

Explanation:

To solve this, we recall the definitions of acids, bases, and pH. Acids are substances that release hydrogen ions ($H^+$) in solution, so they have a higher concentration of hydrogen ions than bases (which release hydroxide ions, $OH^-$). The pH scale is logarithmic, where $pH = -\log[H^+]$. A higher hydrogen ion concentration means a lower pH (since the negative log of a larger number is smaller). So an acid has a higher $[H^+]$ and lower pH than a base.

Answer:

An acid has a higher concentration of hydrogen ions and a lower pH than a base. (The option with this description, likely the second option in the list provided in the problem's choices)