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Calculate the pH of 0.750 M pyridinium chloride, CH₃NHCl? Given K of C₅H₅N is 1.70x10⁻⁹​.

a) Acidic
b) Basic
c) Neutral
d) Cannot be determined

User Gandalf
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1 Answer

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Final answer:

The pH of the 0.750 M pyridinium chloride solution is acidic.

Step-by-step explanation:

To calculate the pH of a solution, we need to consider the dissociation of the compound. In this case, the pyridinium chloride, CH₃NHCl, can act as both an acid and a base. The dissociation of CH₃NHCl can be represented as CH₃NH⁺ + Cl⁻. Since the compound can donate a hydrogen ion (H⁺), it can be considered an acid. To determine the pH, we need to calculate the concentration of H⁺ ions in the solution. We can use the equilibrium constant, Ka, to find that.

The equilibrium constant equation for this dissociation is Ka = [CH₃NH⁺][Cl⁻] / [CH₃NHCl].

Given the concentration of CH₃NHCl as 0.750 M, we can assume that the concentration of CH₃NH⁺ and Cl⁻ will also be 0.750 M since the compound is fully dissociated. To use Ka, we plug in the values and rearrange the equation to solve for the concentration of H⁺ ions:

Ka = [H⁺][Cl⁻] / [CH₃NHCl]

[H⁺] = Ka x [CH₃NHCl] / [Cl⁻]

Substituting the values, we get:

[H⁺] = (1.70x10⁻⁹) x (0.750) / (0.750) = 1.70x10⁻⁹ M

The pH is a measure of the concentration of H⁺ ions in a solution. In this case, the concentration of H⁺ ions is 1.70x10⁻⁹ M, which is very low. Therefore, the pH would be close to 0, indicating that the solution is acidic.

User Aledujke
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