Q79E - Chemistry (OpenStax)

Question

Titration of a 20.0-mL sample of acid rain required 1.7 mL of 0.0811 M NaOH to reach the end point. If we assume that the acidity of the rain is due to the presence of sulfuric acid, what was the concentration of sulfuric acid in this sample of rain?

Step-by-Step Solution

Answer

0.0068 M was the concentration of sulfuric acid in the sample of rain.

Given Data

\({M_a}{V_a} = {M_b}{V_b}\)

a = acid = H₂SO₄   and b = base=NaOH

Volume of acid = 20 mL

Volume of base = 1.7 mL

Molarity of base = 0.0811 M

Molarity of acid =  ?

Determine the concentration of sulfuric acid

\(\begin{aligned}{\underline{\phantom{xx}}}{M_a}{V_a} &= {M_b}{V_b}\\{M_a} \times 20\,mL &= 0.0811\,M \times 1.7\,mL\\{M_a} &= \frac{{0.0811\,M \times 1.7\,mL}}{{20\,mL}}\\{M_a} &= 0.0068\end{aligned}\)