An HCl solution has a concentration of 0.09714 M. Then 10.00 mL of this solution was then diluted to 250.00 mL in a volumetric flask. The diluted solution was then used to titrate 250.0 mL of a saturated AgOH solution using methyl orange indicator to reach the endpoint. Required:
a. What is the concentration of the diluted HCl solution?
b. If 7.93 mL of the diluted HCl solution was required to reach the endpoint, what is the concentration of OH- in solution?

A. Concentration of diluted acid = 0.00389 M

B. Concentration of OH- in AgOH solution = 0.00012 M

Explanation:

A. Using the dilution formula: C1V1 = C2V2

Where C1 is the initial concentration, V1 is the initial volume, C2 is the final concentration, and V2 is the final volume.

From the data provided, C1 = 0.09714 M, V1 = 10.0 mL, V2 = 250.0 mL and C2 = ?

Making C2 subject of the formula above; C2 = C1V1/V2

C2 = 0.09714 M × 10 / 250 = 0.00389 M

B. Equation of the neutralization reaction is given below:

HCl + AgOH ---> AgCl + H₂O

From the equation, 1 mole of acid neutralizes 1 mole of base

Using the titration formula; CaVa/CbVb = na/nb

Where Ca is the concentration of the acid HCl = 0.00389 M

Va is the volume of acid = 7.93 mL

Cb is the concentration of base, AgOH = ?

Vb is volume of base = 250.0 mL

na/nb = mole ratio of acid and base = 1

Making Cb subject of the formula in the equation above; Cb = CaVa/Vb

Cb = 0.00389 M × 7.93 / 250

Cb = 0.00012 M