a 23.74 mL volume of .0981 M NaOH was used to titrate 25 mL of a weak monoprotic acid solution to the stoichiometric point. determine the molar concentration of the weak acid solution. express in correct sig figs.

NaOH + HA ==> NaA + H2O

mols NaOH = M x L = ?
mols HA = mols NaOH (look at the coefficients)
M HA = mols HA/L HA

To determine the molar concentration of the weak acid solution, we can use the concept of stoichiometry and the principles of acid-base titration.

First, let's write down the balanced chemical equation for the reaction between the weak acid (HA) and sodium hydroxide (NaOH):

HA + NaOH -> NaA + H2O

From the equation, we can see that one mole of weak acid reacts with one mole of NaOH, resulting in one mole of sodium salt (NaA) and water (H2O).

The volume and concentration of NaOH used in the titration are given as 23.74 mL and 0.0981 M, respectively. To find the number of moles of NaOH used, we can apply the formula:

moles of NaOH = volume of NaOH (in liters) * concentration of NaOH

Converting the volume from milliliters to liters:

volume of NaOH = 23.74 mL = 23.74 mL * (1 L / 1000 mL) = 0.02374 L

Calculating the moles of NaOH:

moles of NaOH = 0.02374 L * 0.0981 M = 0.002328 mols

Since the weak acid and NaOH react in a 1:1 ratio, the moles of the weak acid are also 0.002328 moles.

Now, let's consider the volume of the weak acid solution used in the titration, which is given as 25 mL. To find the concentration of the weak acid, we rearrange the formula for moles:

concentration of weak acid = moles of weak acid / volume of weak acid (in liters)

Converting the volume from milliliters to liters:

volume of weak acid = 25 mL = 25 mL * (1 L / 1000 mL) = 0.025 L

Calculating the concentration of the weak acid:

concentration of weak acid = 0.002328 mols / 0.025 L = 0.0931 M

Now, we have found the molar concentration of the weak acid solution to be 0.0931 M. To express this value in the correct significant figures, we look at the given data. The volume of NaOH is given to three decimal places (23.74 mL), so we can express our final answer with three decimal places as well. Therefore, the molar concentration of the weak acid solution is 0.093 M (rounded to three decimal places).

Please note that the significant figures may vary depending on the precision of the given data.

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