Question

Questions 3, 4, & 5 pls

(3) You will titrate a solution of an unknown acid (HX(aq)) by adding NaOH(aq). Suppose that 25 mL of 0.5 M NaOH(aq) is needed to reach the equivalence point. How many moles of HX were present initially? Show the calculation. (4) You will titrate acid solutions by adding 0.2-0.3-mL or 2-3-mL portions of NaOH(aq). When should you add the smaller volume? (5) The concentration of an aqueous solution of NaOH cannot be accurately determined by dissolving a known mass of NaOH(s) in a known volume of water: Why? Experiment 7. Acid-base titration

Answer 1

3) Moles of HX = moles of NaOH = Molarity * Volume = 0.5 * 25 * 10^-3 = 1.25 * 10^-2 moles

4) The smaller value needs to be added when we approach close to the equivalence point so that the moles of acid can be accurately determined

5)This is because NaOH does not reac with NaoH. There are no reaction staking place that allow us to measure the number of moles initially present