To calculate the concentration of the acid ($[HX]$), we can use the titration formula:

$M_1 \times V_1 = M_2 \times V_2$

where:

• $M_1$ is the molarity of the acid (unknown),
• $V_1$ is the volume of the acid,
• $M_2$ is the molarity of the base (given as 1.0 M),
• $V_2$ is the volume of the base at the endpoint (25.2 mL).

Let's assume:

1. The volume of the acid is $V_1$ (in mL), which would be known from the initial setup but is not specified here.
2. The molarity of the base $M_2 = 1.0 \, \text{M}$.
3. The volume of the base at the endpoint $V_2 = 25.2 \, \text{mL}$.

The equation rearranges to:

$M_1 = \frac{M_2 \times V_2}{V_1}$

Once we have the volume of the acid $V_1$, we can plug in the values and solve for $M_1$, the concentration of the acid.

Could you provide the volume of the acid $V_1$ if known? Or do you have any other questions?

Here are some related questions for further exploration:

1. What is the relationship between the equivalence point and the endpoint in titration?
2. How would the concentration of the acid change if the molarity of the base were lower than 1.0 M?
3. How can you identify the equivalence point on a titration curve?
4. Why is it important to know the concentration of an acid or base in a solution?
5. How does a pH indicator function in a titration experiment?

Tip: Always double-check units when performing calculations in titration problems, especially when dealing with volumes and molarity.