Which of the following is more acidic? A solution with pH 5 or a solution with pH 3
We know that pH equals to - log[H+] or the value of pH is inversely proportional to the concentration of H+. So more the value of pH, less the solution be acidic.
Ionic product of water is
Which one of the following is the approximate pH of 0.01 M solution of NaOH at 298 k?
First off, since NaOH is a strong base, it will dissociate completely into Na+ and OH-. Thus, we know that we have 0.01 M OH-.
However, we do not know anything about the concentration of H+. Fortunately, we do not need to, as pH + pOH = 14. So, if we find pOH, we can solve for pH. p is a mathematical function equivalent to -log. So, pH actually means -log[H+] (Note that brackets indicate concentration of).
pOH = -log 0.01M OH-
pOH = 2
pH + 2 = 14
pH = 12
This result makes sense, since a solution of strong base should have a high pH.
A 0.10 M solution of a weak acid, HX, is 0.059% ionized. Evaluate Ka for the acid.
Since the acid is only 0.059% ionized, therefore the concentration of ions in solution = 0.1 x 0.059 / 100 = 0.000059
Ka = [H+] [X–] / [HX] = (0.000059)2 / 0.1 = 3.5 x 10-8
In a sample of pure water, only one of the following statements is always true at all conditions of temperature and pressure.
The pH of 10-8 molar solution of HCl in water is:
If we use the relation, pH = – log [H3O+], we get pH equal to 8. But this is not correct because an acidic solution cannot have pH greater than 7. It may be noted that in very dilute acidic solution, when H+ concentrations from acid and water are comparable, the concentration of H+ from water cannot be neglected.
Which one of the following is correct for a solution in which [H+] = 10-8 M.
Which one of the following is a wrong derivation?
Value of pH is determined by
The pH of a 0.02 M solution of an unknown weak acid is 3.7. What is the pKa of this acid?