Question

G the normal range of the ph of blood is between 7.35 and 7.45; variations beyond this range have significant health implications. Calculate the hydrogen ion concentrations ([h+]) associated with these ph values.

Answer 1

Answer : the hydrogen ion concentrations for pH = 7.35 and pH = 7.45 are 4.46 x 10⁻⁸ M and 3.54 x 10⁻⁸ M respectively.

When the pH of a solution is less than 7, the hydrogen ion concentration is higher and therefore the solution is acidic.

On the other hand, when the pH of a solution is greater than 7, hydroxide ion concentration is higher and the solution acts as a base.

The normal pH range of blood is given as 7.35 - 7.45  which is greater than 7. That means blood is slight basic in nature.

Let us find hydroxide ion concentration of blood.

$pH + pOH = 14$

$7.35 + pOH = 14$

$pOH = 6.65$

$pOH = - log [OH-]$

$[OH-] = 10^{-6.65}$

$[OH-] = 2.24 \times 10^{-7}$

Ionic product of water is written as,

$[H+] [OH-] = 1 \times 10^{-14}$

Let us plug in the calculated value of [OH-]

$[H+] = \frac{1 \times 10^{-14}}{2.24 \times 10^-7} = 4.46 \times 10^{-8} M$

The hydrogen ion concentration for pH = 7.35 is 4.46 x 10⁻⁸ M

Calculation of [H+] for pH = 7.45

pOH = 6.55

[OH-] = 2.82 x 10⁻⁷

$[H+] = \frac{1 \times 10^{-14}}{2.82 \times 10^-7} = 3.54 \times 10^{-8} M$

Similarly, for pH = 7.45, we get hydrogen ion concentration of 3.54 x 10⁻⁸ M.