Question

chapter 3: chemistry of life: breaking good
page(s) 56-58
3.6. predict whether a solution has a high or low concentration of free hydrogen ions by using its ph number.
order the following from the lowest concentration of free hydrogen ions to the highest.
start by choosing the first item in the sequence and clicking, dragging, or using your keyboard to select it.
drag the items below into the box above in the correct order, starting with the first item in the sequence.
milk with a ph of 6.5
washing soda with a ph of 8–10
a solution of h₂so₄ with a ph of 2

Explanation:

Step1: Recall pH and H⁺ relation

The pH scale is related to the concentration of hydrogen ions ($[\text{H}^+]$) by the formula $\text{pH} = -\log_{10}[\text{H}^+]$. A higher pH means a lower $[\text{H}^+]$, and a lower pH means a higher $[\text{H}^+]$.

Step2: Analyze each solution's pH

• Washing soda has a pH of 8 - 10. Let's take the mid - range or consider that 8 - 10 is higher than 6.5 and 2.
• Milk has a pH of 6.5, which is lower than 8 - 10 but higher than 2.
• The $\ce{H_2SO_4}$ solution has a pH of 2, which is the lowest pH among the three.

Step3: Order by $[\text{H}^+]$ (low to high)

Since lower pH means higher $[\text{H}^+]$ and higher pH means lower $[\text{H}^+]$, the order from lowest $[\text{H}^+]$ (highest pH) to highest $[\text{H}^+]$ (lowest pH) is: washing soda (pH 8 - 10), milk (pH 6.5), $\ce{H_2SO_4}$ solution (pH 2).

Answer:

1. washing soda with a pH of 8 - 10
2. milk with a pH of 6.5
3. a solution of $\ce{H_2SO_4}$ with a pH of 2