Respuesta :
Answer:
pH = 6.86
Explanation:
Even though HCl is a strong acid, it is so diluted in water that we have to consider the concentration of H+ ions in water.
Thus, pH will be measured after getting total [H+] (adding up [H+] from HCl and water).
[H+] of HCl is given, 6.4× 10^–8
[H+] of water is measured knowing
- Kw = [H+][OH-] = 10^-14, because its water
[H+][OH-] is found by dissosiation of water
H2O -> H+ and O-
I 6.4× 10^–8 0
C +x +x
E 6.4× 10^–8 + x x
*concentration of H2O removed because its not needed
Kw = [6.4× 10^–8 + x] [x]
10^-14 = [6.4× 10^–8 + x] [x]
do the quadratics...
x= 7.30×10^-8
- ignore the negative root
total [H+] = 6.4× 10^–8 + x
= (6.4× 10^–8) + (7.30×10^-8)
= 1.37 × 10^-7
pH = -log[total H+]
pH = -log[1.37 × 10^-7]
ph = 6.86
