Constants Periodic Table PartA magine that you are in chemistry lab and need to
ID: 636624 • Letter: C
Question
Constants Periodic Table PartA magine that you are in chemistry lab and need to make 1.00 L of a solution with a pH of 2.40. Assuming the final solution will be diluted to 1.00 L, how much more HCl should you add to achieve the desired pH? You have in front of you Express your answer to three significant figures and include the appropriate units 100 mL of 7.00x10-2 MHCL, View Available Hint(s) 100 InL of 5.00x10 2 M NaOH and plenty of distilled water. You start to add HCl to a beaker of water when someone asks you a question. When you return to your dilution, you accidentally grab the wrong cylinder and add some NaOH. Once you realize your error, you assess the situation. You have 82.0 mL of HCl and 89.0 mL of NaOH left in their original containers Value Units SubmitExplanation / Answer
No of mol of HCl added = V*M = (100-82)*0.07 = 1.26 mmol
NO of mol of NaOH added accidentally = (100-89)*0.05 = 0.55 mmol
No of mol of HCl left in solution = 1.26-0.55 = 0.71 mmol
total mol of H+ required to reach desired pH = 10^-pH
= 10^-2.4
= 0.004 M
= 0.004 mol ( as volume of diluted solution = 1 L)
= 4 mmol
extra no of mol HCl must be added = 4-0.71 = 3.29 mmol
volume of HCl must be added = 3.29/0.07 = 47 ml
answer: 47.0 ml