Question

NORTHERN MICHIGAN UNIVERSITY CH112: Acid-Base Titration: Determining the Concentration of an Acid Solution Student Name: PRE-LAB (to be checked by the instructor before beginning the lab) 1. A 10.0 mL sample of hydrochloric acid is diluted by adding 50 mL of deionized water, and then titrated with a 0.1245 M solution of sodium hydroxide. If 26.75 mL of the sodium hydroxide solution are required to reach the equivalence point, what is the concentration of the original hydrochloric acid solution? 2. If 8.0 mL of a different hydrochloric acid solution had a known concentration of 0.3456 M, how many mL of the 0.1245 M NaOH solution would be required to reach the equivalence point?

Answer 1

1) Let's assum, the concentpation of original HCl solution am .: 1000 ml of the solution contains a mol HCL :: 10 ml of the solution contains x 10 100 To o mol HCL After adding 50 ml water the total volume of the solution will be (10+50)=60 ml :: Concentration of the diluted HCl solution is = 100 x 1000 => *M Now, we know in acid-base titration reaction - VHCLXSHCL = V NaOH XSNaOH T = volume, S = strength] putting the values 60x = 26.75X0.1345 Or, x= 0.3330 (m) Am. The concentration of the original HCL solution is 0.3330m

2. As we know, VHCL XSHCl = VNGOH XS NaOH Putting the values 8 x 0.3456 = VNqOH X 0.1245 Our VNGOH = 22.21 ml AM: 22.21 ml NaOH would be requiped to reach the equivalence point.