Question

properties unit test
what is the ph of a (1 \times 10^{-4}) mol hcl solution? (1 point)

• 4

○ 8
○ 2
○ 6

Explanation:

Step1: Recall pH formula

The formula for pH is $pH = -\log_{10}[H^+]$, where $[H^+]$ is the hydrogen ion concentration.

Step2: Determine $[H^+]$ for HCl

HCl is a strong acid, so it dissociates completely in water: $HCl
ightarrow H^+ + Cl^-$. For a $1\times10^{-4}\ mol/L$ HCl solution, the $[H^+]$ is also $1\times10^{-4}\ mol/L$ (since 1 mole of HCl gives 1 mole of $H^+$).

Step3: Calculate pH

Substitute $[H^+] = 1\times10^{-4}$ into the pH formula: $pH = -\log_{10}(1\times10^{-4})$. Using the logarithm property $\log_{10}(10^x)=x$, we have $-\log_{10}(10^{-4}) = -(-4)=4$.

Answer:

4