Question

Antacid has a pH of 11. What does that tell you about its concentration of hydrogen ions? What does that tell you about its concentration of hydroxide ions?

Answer 1

Answer: The concentration of hydrogen ions is $10^{-11}M$ and the concentration of hydroxide ions is $10^{-3}M$. Thus the concentration of hydroxide ions is more than the concentration of hydrogen ions.

Explanation:

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration.  

$pH=-\log [H^+]$

$pOH=-\log[OH^-]$

Putting in the values:

$11=-\log[H^+]$

$[H^+]=10^{-11}M$

$pH+pOH=14$

$pOH=14-11=3$

$3=-log[OH^-]$

$[OH^-]=10^{-3}M$

Thus the concentration of hydroxide ions is more than the concentration of hydrogen ions.