Answer:
11.4
Explanation:
Step 1: Given data
- Concentration of the base (Cb): 0.300 M
- Basic dissociation constant (Kb): 1.8 × 10⁻⁵
Step 2: Write the dissociation equation
NH₃(aq) + H₂O(l) ⇄ NH₄⁺(aq) + OH⁻(aq)
Step 3: Calculate the concentration of OH⁻
We will use the following expression.
[tex][OH^{-} ]=\sqrt{Kb \times Cb } = \sqrt{1.8 \times 10^{-5} \times 0.300 } = 2.3 \times 10^{-3} M[/tex]
Step 4: Calculate the pOH
We will use the following expression.
[tex]pOH =-log[OH^{-} ]= -log(2.3 \times 10^{-3} M) = 2.6[/tex]
Step 5: Calculate the pH
We will use the following expression.
[tex]pH+pOH=14\\pH = 14-pOH = 14-2.6 = 11.4[/tex]
