[NaOH]= 0.113M

V of NaOH needed to titrate = 0.0037L
V of unknown weak organic acid = 0.025L

Find:
The initial concentration of this weak acid.

If it's a monoprotic weak acid, then

L acid x M acid = L NaOH x M NaOH

Ok How do I find the initial concentration of the acid?

Substitute the numbers from the problem and solve for M acid.

To find the initial concentration of the weak organic acid, we can use the concept of stoichiometry and the balanced equation for the reaction between the weak organic acid and NaOH.

The balanced equation for the reaction can be represented as follows:

Weak Acid (HA) + NaOH → NaA (Salt) + H2O

From the balanced equation, we can see that the stoichiometric ratio between the weak acid (HA) and NaOH is 1:1. This means that for every mole of NaOH used, there is one mole of weak acid reacted.

First, let's calculate the number of moles of NaOH used in the titration:

Moles of NaOH = Molarity of NaOH × Volume of NaOH used
= 0.113 M × 0.0037 L
= 0.0004181 moles

Since the stoichiometric ratio between NaOH and HA is 1:1, the number of moles of weak acid (HA) is also 0.0004181 moles.

Next, we need to calculate the initial concentration of the weak acid (HA). To do this, we'll divide the number of moles of HA by the initial volume of the weak acid solution:

Initial concentration of HA = Moles of HA / Volume of weak acid
= 0.0004181 moles / 0.025 L
= 0.0167 M

Therefore, the initial concentration of the weak organic acid is 0.0167 M.