Question

use the following information to answer the next question.
a solution was prepared by dissolving 0.32 g of
ba(oh)₂(s) in enough water to form 1 l of solution.
the ph of the barium hydroxide solution is
12.251
10.261
11.47
13.512
2.43
question 4 (1 point)
which of the following species is neither an acid or a base as defined by bronsted-lowry?
hpo₄²⁻
alcl₃
nh₃
co₃²⁻
all of these are either an acid or a base as defined by bronsted-lowry.

Explanation:

First Question (pH of Barium Hydroxide Solution)

Step1: Calculate moles of Ba(OH)₂

Molar mass of \( \text{Ba(OH)}_2 \) is \( 137.33 + 2\times(16 + 1.008) = 171.346 \, \text{g/mol} \). Moles \( = \frac{0.32 \, \text{g}}{171.346 \, \text{g/mol}} \approx 0.001867 \, \text{mol} \).

Step2: Determine \( [\text{OH}^-] \)

\( \text{Ba(OH)}_2 \) dissociates as \( \text{Ba(OH)}_2
ightarrow \text{Ba}^{2+} + 2\text{OH}^- \), so \( [\text{OH}^-] = 2 \times 0.001867 \, \text{mol/L} \approx 0.003734 \, \text{M} \).

Step3: Calculate pOH

\( \text{pOH} = -\log(0.003734) \approx 2.428 \).

Step4: Calculate pH

\( \text{pH} = 14 - 2.428 \approx 11.572 \) (closest to 11.47 due to rounding differences). Wait, recalculating moles: \( 0.32 / 171.34 \approx 0.001867 \), \( [\text{OH}^-] = 2\times0.001867 = 0.003734 \), \( \text{pOH} = -\log(0.003734) \approx 2.428 \), \( \text{pH} = 14 - 2.428 = 11.572 \). But the option 11.47 is close. Maybe more precise: molar mass of Ba(OH)₂ is 171.34 g/mol. 0.32 g / 171.34 g/mol = 0.001867 mol. [OH⁻] = 20.001867 = 0.003734 M. pOH = -log(0.003734) = 2.428, pH = 14 - 2.428 = 11.572. Wait, maybe my molar mass is slightly off? Let's check: Ba is 137.33, O is 16, H is 1.008. So 137.33 + 2(16 + 1.008) = 137.33 + 34.016 = 171.346. Correct. Alternatively, maybe the question's answer is 11.47. So the closest option is 11.47.

• \( \text{HPO}_4^{2-} \): Can accept or donate H⁺ (amphoteric, so acid/base).
• \( \text{AlCl}_3 \): Lewis acid, but Bronsted-Lowry defines acid as H⁺ donor, base as H⁺ acceptor. \( \text{AlCl}_3 \) doesn't involve H⁺ transfer, so neither.
• \( \text{NH}_3 \): Accepts H⁺ (base).
• \( \text{CO}_3^{2-} \): Accepts H⁺ (base).

Answer:

11.47

Second Question (Bronsted-Lowry Acid/Base)