0.8 Molar NaOH is added to 30 mL of HCI and the volume of base added vs. pH is graphed.

What molarity is the HCI solution?

To find the molarity of the HCI solution, we need to use the equation:

M1V1 = M2V2

where:
M1 = molarity of NaOH
V1 = volume of NaOH (in L)
M2 = molarity of HCI solution
V2 = volume of HCI solution (in L)

From the problem, we know:
M1 = 0.8 M
V1 = 30 mL = 30/1000 L = 0.03 L
V2 = volume of HCI solution (unknown)

We need to rearrange the equation to solve for M2:

M2 = (M1V1) / V2

Plugging in the given values:

M2 = (0.8 M * 0.03 L) / V2

To determine the molarity of the HCI solution, we need more information or the values for the volume of base added (V2) and the corresponding pH values.