Question

A 25.0-milliliter sample of HNO3 (aq) is neutralized by 32.1 milliliters of 0.150 M KOH (aq). What is the concentration of the acid?

Answer 1

Answer:

0.193 M of acid.

Explanation:

To find the concentration of the acid, we're going to use the following formula:

$C_1V_1=C_2V_2.$

Where C is concentration and V the volume. Subindex 1 can indicate the concentration and volume of the acid (HNO3) and subindex 2 can indicate the concentration and volume of the base (KOH).

In this case, we want to find C1, so let's clear the formula for this incongnite:

$C_1=\frac{C_2V_2}{V_1}.$

And finally, we replace the given data, like this:

$C_1=\frac{0.150\text{ M}\cdot32.1mL}{25.0\text{ mL}}=0.193\text{ M.}$

The concentration of acid would be 0.193 M.