Answer:
[tex]\large \boxed{20 \,000}[/tex]
Explanation:
pH = -log[H⁺], so
[tex]\text{[H$^{+}$]} = 10^{\text{-pH}}[/tex]
At pH 6.4,
[tex]\text{[H$^{+}$]} = 10^{-6.4}[/tex]
At pH 10.7,
[tex]\text{[H$^{+}$]} = 10^{-10.7}[/tex]
The ratio of the two concentrations is
[tex]\text{Ratio}= \dfrac{10^{-6.4}}{10^{-10.7}} = 10^{(10.7 - 6.4)} = 10^{4.3} = \mathbf{2 \times 10^{4}}\\\text{The ratio of the two concentrations is a factor of $\large \boxed{\mathbf{20 \, 000}}$}[/tex]
