posted by Jenn .
A 495-mL sample of unknown HCl solution reacts completely with Na2CO3 to form 18.1g CO2. What was the concentration of the HCl solution?
Same process. Write the balanced equation. Convert g CO2 to mols with mols = grams/molar mass. Use the coefficients to convert mols CO2 to mols HCl. Then M HCl = mols HCl/L HCl.