At a pH of 7.10, the H+ concentration is equal to

At a pH of 7.10, the H+ concentration is equal to

• A. 80 nmol/L
• B. 20 nmol/L
• C. 40 nmol/L
• D. 60 nmol/L

Answer: (A)

The key idea is that pH is the negative logarithm of the hydrogen ion concentration: pH = -log10[H+]. So the hydrogen ion concentration is [H+] = 10^(-pH) in moles per liter. For pH 7.10, [H+] = 10^(-7.10) M ≈ 7.94 × 10^(-8) M. Converting to nanomoles per liter: 7.94 × 10^(-8) M × 10^9 nmol/L per M ≈ 79.4 nmol/L, which rounds to about 80 nmol/L. Therefore, at pH 7.10, the H+ concentration is approximately 80 nmol/L.

The key idea is that pH is the negative logarithm of the hydrogen ion concentration: pH = -log10[H+]. So the hydrogen ion concentration is [H+] = 10^(-pH) in moles per liter. For pH 7.10, [H+] = 10^(-7.10) M ≈ 7.94 × 10^(-8) M. Converting to nanomoles per liter: 7.94 × 10^(-8) M × 10^9 nmol/L per M ≈ 79.4 nmol/L, which rounds to about 80 nmol/L. Therefore, at pH 7.10, the H+ concentration is approximately 80 nmol/L.