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Calculate pH of a 0.35 M CH3COOLi solution.

Note: Ka for acetic acid is 1.75*10^-5

User Artier
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1 Answer

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To calculate the pH of the solution, we need to consider the dissociation of acetic acid.

CH3COOH + H2O ⇌ CH3COO- + H3O+

The equilibrium constant expression for the dissociation of acetic acid is:

Ka = [CH3COO-][H3O+]/[CH3COOH]

At equilibrium, the concentration of CH3COOH will be decreased by x and the concentrations of CH3COO- and H3O+ will be increased by x. Therefore, we can assume that the initial concentration of CH3COOH is equal to the concentration of CH3COO- and H3O+.

Let x be the concentration of H3O+ and CH3COO- at equilibrium.

Ka = x^2 / (0.35 - x)

Since the value of x is small compared to 0.35, we can simplify the equation by assuming that 0.35 - x ≈ 0.35.

Ka = x^2 / 0.35

Rearranging the equation, we can solve for x:

x = √(Ka * 0.35) = √(1.75*10^-5 * 0.35) = 1.49*10^-3 M

The pH of the solution can be calculated using the concentration of H3O+:

pH = -log[H3O+] = -log(1.49*10^-3) = 2.83

Therefore, the pH of a 0.35 M CH3COOLi solution is 2.83.
User Slatvick
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