Answer:
161 mL
Explanation:
First we calculate how many Pb⁺² moles reacted, using the given concentration and volume of the Pb(NO₃)₂ solution:
As 1 millimol of Pb(NO₃)₂ would react with 1 millimol of Ba(OH)₂, to precipitate 107 mmoles of Pb(NO₃)₂ we would require 107 mmoles of Ba(OH)₂.
Using the number of moles and the concentration we can calculate the required number of milliliters: