Acidity-Basicity Of An Aqueous Solution
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Acidity-Basicity Of An Aqueous Solution

Assuming complete ionization, determine:
(a) the pH of 0.0001 N HCl (Hydrocloric acid)
(b) the pOH of KOH (potassium hydroxide)

The strings:

S7P5A51 (Change - Physical Change).

The math:
Pj Problem of Interest is of type change (physical change).

pH = -log[H+], where [H+] is hydrogen ion concentration.
pOH = -log[OH-], where [OH-] is hydroxide ion concentration.
Normality (N) = number of equivalents of H+ per liter of solution.

(a) ionization of HCl:
HCl <-------> H+ + Cl- ----(1)
Reaction (1) indicates [H+] = [HCl] since ionization is complete
So, [H+] = 0.0001 = 10-4 N (normality = molarity)
So, pH = -log10-4 = 4.

(b) ionization of KOH:
KOH <-------> Na+ + OH- ----(2)
Reaction (2) indicates [OH-] = [KOH] since ionization is complete
So, [OH-] = 0.0001 = 10-4 N (normality = molarity)
So, pOH = -log10-4 = 4.

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