Answer :
To find the volume of 0.200 M NaOH required to reach the equivalence point in a titration against 33.00 mL of 0.140 M HBr, we calculate the moles of HBr, then use the molarity of NaOH to find its volume, which is approximately 23.1 mL, with the closest answer being a) 23.6 mL.
To calculate the volume of NaOH needed to titrate 33.00 mL of 0.140 M HBr to the equivalence point, we use the concept of molarity and the stoichiometry of the reaction that occurs between NaOH (a strong base) and HBr (a strong acid). In a reaction between a strong acid and a strong base, they neutralize each other in a 1:1 molar ratio.
To find the equivalence point, the moles of HBr must equal the moles of NaOH. The initial moles of HBr are calculated as follows:
Moles of HBr = Molarity of HBr × Volume of HBr = 0.140 M ×0.033 L = 0.00462 moles
Since the ratio is 1:1, the moles of NaOH needed are also 0.00462. Using the molarity of NaOH, we can find its required volume:
Volume of NaOH = Moles of NaOH \/ Molarity of NaOH = 0.00462 moles \/ 0.200 M = 0.0231 L
Convert the volume to mL, since 1 L = 1000 mL:
Volume of NaOH = 0.0231 L × 1000 mL/L = 23.1 mL
Therefore, the closest answer to the calculated volume (23.1 mL) is 23.6 mL (option a).
