Question

i need help with understanding 7a,7b, and 7c

A 2 M NaOH is used to titrate 1000 mL of a solution of HCI (hydrochloric acid), the concentration of which is unknown. If 100 mL of 2 M NaOH is required to neutralize the HCI solution: 7. How many moles of NaOH were added? How many moles of HCI were present in the unknown solution? What was the concentration of the unknown solution of HCI?

Answer 1

Titration picture let, concentration of unknown HCl in x (M) we know ml times molarity (M) = milimole therefore 100 ml times 2(M) = 200 milimole = 0.2 mole therefore 0.2 moles of NaOH were added we know V_1 S_1 = V_2 S_2 or, S_2 = V_1 times S_1/V_2 or, strength of HCl = volume of NaOH times strength of NaOH/volume of HCl or, x = 100 ml times 2(M)/1000 ml or, x = 0.2(M) = > concentration of unknown HCl ml times (M) = milimole therefore 1000 times 0.2(M) = 200 milimole = 0.2 mole therefore 0.2 mole of HCl mm present in unknown solution.