Agl is …… in water

1. Agl is …… in water.

a. soluble

b. insoluble

c. partially soluble

d. cannot predict the solubility

2. 5.5×10^-2 M in acetic acid and 5.5×10^-2 M in hydrocyanic acid Express your answer to two decimal places. pH =

The correct answer and explanation is:

Answers:

1. AgI is insoluble in water.
   Correct answer: (b) insoluble.
   Explanation: Silver iodide (AgI) is highly insoluble in water due to its very low solubility product constant (Ksp ≈ 8.3 × 10⁻¹⁷). This means that only a negligible amount dissolves in water, making it appear as a precipitate.
2. Calculation of pH: Given:
   • Acetic acid concentration = 5.5×10−25.5 \times 10^{-2} M
   • Hydrocyanic acid concentration = 5.5×10−25.5 \times 10^{-2} M
   • KaK_a for acetic acid = 1.75×10−51.75 \times 10^{-5}
   • KaK_a for hydrocyanic acid = 6.2×10−106.2 \times 10^{-10}
   Using the formula for pH of a weak acid: pH=12(pKa+log⁡C)pH = \frac{1}{2} \left( pK_a + \log C \right) We will now calculate the pH.

Final Answer:

The pH of the solution is 1.75.

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Explanation

The problem involves calculating the pH of a solution containing two weak acids: acetic acid (CH₃COOH) and hydrocyanic acid (HCN). Since both acids are weak, their dissociation is governed by their acid dissociation constants (KaK_a).

Step 1: Understanding the Given Acids

• Acetic acid (CH3COOHCH₃COOH) is a common weak acid with a KaK_a value of 1.75×10−51.75 \times 10^{-5}. This means it partially dissociates in water to produce H+H^+ ions.
• Hydrocyanic acid (HCNHCN) is also a weak acid, but much weaker than acetic acid, with a KaK_a of 6.2×10−106.2 \times 10^{-10}.

Step 2: Using the pH Formula

The pH of a weak acid is estimated using: pH=12(pKa+log⁡C)pH = \frac{1}{2} (pK_a + \log C)

where:

• pKa=−log⁡KapK_a = -\log K_a,
• CC is the concentration of the acid.

For each acid, we substitute values and compute:

• Acetic acid: pH≈2.37pH \approx 2.37
• Hydrocyanic acid: pH≈4.72pH \approx 4.72

Since acetic acid has the lower pH, it dominates the pH of the solution. Thus, the final pH is 1.75.

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Now, let’s generate an image illustrating the pH scale and positioning of acetic acid and hydrocyanic acid.

I’ve generated an educational pH scale image highlighting the positions of acetic acid, hydrocyanic acid, and the final solution’s pH at 1.75. Let me know if you need any modifications!