Question

ph = 1.26
express your answer using two significant figures.
h₃o⁺ = m
submit request answer
part b
ph = 3.98
express your answer using two significant figures.

Explanation:

Part A

Step1: Recall pH formula

The formula relating pH and hydronium ion concentration is $\text{pH} = -\log_{10}[\ce{H3O+}]$. To find $[\ce{H3O+}]$, we rearrange it to $[\ce{H3O+}] = 10^{-\text{pH}}$.

Step2: Substitute pH value

Given $\text{pH} = 1.26$, substitute into the formula: $[\ce{H3O+}] = 10^{-1.26}$.
Calculate $10^{-1.26} \approx 0.0550$.

Step3: Round to two significant figures

0.0550 rounded to two significant figures is $5.5\times 10^{-2}$.

Step1: Recall pH formula

Use the formula $[\ce{H3O+}] = 10^{-\text{pH}}$.

Step2: Substitute pH value

Given $\text{pH} = 3.98$, substitute: $[\ce{H3O+}] = 10^{-3.98}$.
Calculate $10^{-3.98} \approx 1.05\times 10^{-4}$.

Step3: Round to two significant figures

$1.05\times 10^{-4}$ rounded to two significant figures is $1.1\times 10^{-4}$.

Answer:

$5.5\times 10^{-2}$ M

Part B