Calculate the ratio of H+ ions to OH– ions at a pH = 6. Find the concentration of H+ ions to OH– ions listed in Table B of your Student Guide. Then divide the H+ concentration by the OH– concentration. Record this calculated ratio in Table A of your Student Guide. Compare your approximated and calculated ratios of H+ ions to OH– ions at a pH = 6. Are they the same? Why or why not? Record your explanation in Table A. What is the concentration of H+ ions at a pH = 6? mol/L What is the concentration of OH– ions at a pH = 6? mol/L What is the ratio of H+ ions to OH– ions at a pH = 6?

You must know the concept of pH of a solution and its relation to the concentration of H+ and OH- ions. pH is a measure of the substance's acidity or basicity. From the definition of Arrhenius, an acid contains an H+ while a base contains a OH- ion. From this definition, we can say that an acidic substance has a higher concentration of H+ ions. Now, I'll introduce here that pH is the value of the negative logarithm of the concentration of H+. In equation,

pH = -log[H+]

The term pOH is therefore also, pOH = -log[OH-]. Therefore, the relationship that connects the two negative logarithms is:

pH + pOH = 14

The pH scale starts from 1 being the most acidic to 14 being the most basic. The neutral pH is 7. Thus, for a pH of 7, the H+ and the OH- concentrations are equal.

pH = 7 = -log[H+]

[H+] = 1×10⁻⁷ mol/L = [OH-]

Since the concentrations are equal, the ratio is equal to 1.