Answer:
The pH of the new HCl solution is 0.53.
Explanation:
Volume of the HCl solution [tex]V_1= 100 ml=0.1 L[/tex]
Molarity of HCl solution ,[tex]M_1= 2.5 M[/tex]
Volume of water added = 100 mL = 0.1 L
Molarity of HCl after addition of 0.75 L of water = [tex]M_2[/tex]
Final volume of the HCl solution after addition of 0.75 L of water = [tex]V_2[/tex]
[tex]V_2=0.75 L + 0.1 L =0.85 L[/tex]
[tex]M_1V_1=M_2V_2[/tex][
[tex]2.5 M\times 0.1 L=M_2\times 0.85 M[/tex]
[tex]M_2=0.2941 M[/tex]
HCl is a monotonic acid and its one mole will give 1 mole of hydrogen ions in aqueous solution.
Molarity of hydrogen ion =[tex][H^+]=0.2941 M[/tex]
[tex]pH=-\log [H^+]=-\log [0.2941 M]=0.53[/tex]
The pH of the new HCl solution is 0.53.
