Answer: 66.66 ml
Explanation: Using Molarity equation:
[tex]M_1V_1[/tex] (stock solution)=[tex]M_2V_2[/tex](solution to be prepared)
given: [tex]M_2=0.750M[/tex]
[tex]V_2=800ml[/tex]
[tex]M_1=9.00M[/tex]
[tex]V_1=?[/tex]
[tex]9.00M\times V_1[/tex] (stock solution)=[tex]0.750M\times 800ml[/tex] (solution)
[tex]V_1= 66.66ml[/tex]