Question

The concentration of CO2 in air is determined by acid–base titration. A 

sample of polluted air is bubbled through a solution containing an excess 

of Ba(OH)2 aqueous solution, precipitating BaCO3. The excess Ba(OH)2 is 

titrated with HCl. 

In a typical analysis a 3.5-L sample of polluted air was bubbled through 

50.00 mL of 0.0200 M Ba(OH)2. Titrating with 0.0316 M HCl required 38.58 

mL to reach the end point. Determine the ppm CO2 in the sample of air 

given that the density of CO2 at the temperature of the sample is 1.98 g/L

Answer 1

$ppM = \frac{1.98}{38.58}×50=2.566$