Studying the Dissociation of CH_3COOH in Water What is the color of the initial
ID: 491314 • Letter: S
Question
Studying the Dissociation of CH_3COOH in Water What is the color of the initial equilibrium mixture (Step 6)? What change do you observe when you add solid CH_3COONa (Step 7)? What change do you observe when you add NaOH solution to the second test tube (Step 8)? Write the chemical equation for the dissociation of CH_3COOH in water. What, if any, experimental evidence do you have that the equilibrium is affected by the addition of solid CH_3COONa (Step 7)? Briefly explain. Are your observation and explanation in (13) consistent with lessthanorequalto Chatelier's principle? Briefly explain. What, if any, experimental evidence do you have that the equilibrium is affected by the addition of NaOH solution (Step 8)? Briefly explain.Explanation / Answer
9]
CH3COOH is a weak acid. It dissociate in water as follow:
CH3COOH CH3COO- + H+
Colors are coming from universal indicator and that red represents a lower pH
10]
When CH3COONa, which is completely dissociated into ions, is added, the concentration of CH3COO- is raised and the equilibrium is shifted to the left, toward un-dissociated CH3COOH. This reduces the concentration of H+ and raises the pH. Hence, the color changes to orange, a higher pH.
11]
When some NaOH was added OH- reacted with some of the H+, lowering momentarily, the concentration of H+. This shifted the equilibrium to the right, making more CH3COO- and H+, and apparently just enough H+ to keep the color of the universal indicator red.
12]
CH3COOH is a weak acid. It dissociate in water as given below
CH3COOH CH3COO- + H+