Calculate the ratio of a pH of a solution containing 1 mole of CH3COON...
Solution 1: CH3COONa + HCl
In this solution, we have 1 mole of CH3COONa and 1 mole of HCl per liter. To determine the ratio of pH, we need to understand the dissociation of these compounds in water.
Dissociation of CH3COONa:
CH3COONa is a salt that dissociates completely in water. It releases CH3COO- ions and Na+ ions. Since CH3COONa is a strong electrolyte, it dissociates as follows:
CH3COONa → CH3COO- + Na+
Dissociation of HCl:
HCl is a strong acid that also dissociates completely in water. It releases H+ ions and Cl- ions. The dissociation of HCl is as follows:
HCl → H+ + Cl-
pH of Solution 1:
The H+ ions released from HCl contribute to the acidity of the solution, resulting in a lower pH. The CH3COO- ions released from CH3COONa do not significantly affect the pH. Therefore, the pH of Solution 1 is determined by the concentration of H+ ions.
Solution 2: CH3COONa + Acetic Acid
In this solution, we have 1 mole of CH3COONa and 1 mole of acetic acid per liter. Acetic acid is a weak acid and does not dissociate completely in water.
Dissociation of Acetic Acid:
Acetic acid partially ionizes in water, releasing H+ ions and CH3COO- ions. The dissociation of acetic acid is as follows:
CH3COOH ⇌ H+ + CH3COO-
pH of Solution 2:
The pH of Solution 2 is determined by the concentration of H+ ions released from the partial dissociation of acetic acid. Since acetic acid is a weak acid, the concentration of H+ ions is lower compared to Solution 1. Therefore, the pH of Solution 2 is higher than the pH of Solution 1.
Comparison:
Comparing the two solutions, we can conclude that Solution 1 (CH3COONa + HCl) has a lower pH compared to Solution 2 (CH3COONa + Acetic Acid). The presence of a strong acid like HCl in Solution 1 results in a higher concentration of H+ ions, leading to higher acidity and a lower pH. Solution 2, on the other hand, has a weaker acid (acetic acid) which only partially ionizes, resulting in a lower concentration of H+ ions and a higher pH.
Therefore, the ratio of the pH of Solution 1 to Solution 2 is 1:2 (C).