Fun Chemistry Problem: Let's Calculate Molarity!

How can we determine the molarity of an NaOH solution from a neutralization experiment?

A student found that 25.55cm^3 of base neutralized exactly 21.35cm^3 of 0.12M NaOH. Find the molarity of the NaOH.

Options: A) 0.05 M, B) 0.10 M, C) 0.15 M, D) 0.20 M

Answer:

In a neutralization reaction, the number of moles of acid equals the number of moles of base. The confirmed molarity of the NaOH solution in this experiment is found to be 0.1M.

Explanation: In standardizing an NaOH solution, a student found that 25.55cm^3 of base neutralized exactly 21.35cm^3 of 0.12M NaOH. The key to solving this problem lies in understanding that the number of moles of acid equal the number of moles of base at the point of neutralization.

Here, we can calculate the number of moles of acid using the formula moles = Molarity x Volume.

First, convert volume from cm^3 to L for acid: 21.35cm^3 = 0.02135L. Next, calculate moles of acid = Molarity x Volume = 0.12M x 0.02135L = 0.002562 moles of acid.

Since moles of acid = moles of base, the moles of base also equals to 0.002562 moles. Now to find the molarity of the base (NaOH):

Again, convert volume from cm^3 to L for base: 25.55cm^3 = 0.02555L. Then, Molarity = moles/volume = 0.002562/0.02555 = 0.1M or Option B).