Question

question
determine the concentration of hydronium ions for a 25°c solution with a poh of 3.5.

• report your answer with the correct number of significant figures using scientific notation.
• note that when taking the exponential of a value, keep as many significant figures in the result as there are decimal

places in the value.

provide your answer below:

m

Explanation:

Step1: Calculate pH

At $25^{\circ}\text{C}$, $pH + pOH=14$. Given $pOH = 3.5$, then $pH=14 - 3.5=10.5$.

Step2: Calculate hydronium ion concentration

The formula for hydronium ion concentration is $[H_3O^+]=10^{-pH}$. Substituting $pH = 10.5$ into the formula, we get $[H_3O^+]=10^{-10.5}$.
Using the property $a^{m + n}=a^m\times a^n$, $10^{-10.5}=10^{-11}\times10^{0.5}$. Since $10^{0.5}=\sqrt{10}\approx3.2$, so $[H_3O^+]=3.2\times10^{-11}\text{ M}$.

Answer:

$3.2\times10^{-11}\text{ M}$