1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Tasya [4]
3 years ago
12

Suppose you have just added 100 ml of a solution containing 0.5 mol of acetic acid per liter to 400 ml of 0.5 m naoh. what is th

e final ph? (the pka of acetic acid is 4.7.)
Chemistry
1 answer:
Tpy6a [65]3 years ago
6 0

pH = 13.5

Explanation:

Sodium hydroxide completely ionizes in water to produce sodium ions and hydroxide ions. Hydroxide ions are in excess and neutralize all acetic acid added by the following ionic equation:

\text{HAc} + \text{OH}^{-} \to \text{Ac}^{-} + \text{H}_2\text{O}

The mixture would contain

  • 0.4 \times 0.5 - 0.1 \times 0.5 = 0.15 \; \text{mol} of \text{OH}^{-} and
  • 0.1 \times 0.5 = 0.05 \; \text{mol} of \text{Ac}^{-}

if \text{Ac}^{-} undergoes no hydrolysis; the solution is of volume 0.1 + 0.4 = 0.5 \; \text{L} after the mixing. The two species would thus be of concentration 0.30 \; \text{mol} \cdot \text{L}^{-1} and 0.10 \; \text{mol} \cdot \text{L}^{-1}, respectively.

Construct a RICE table for the hydrolysis of \text{Ac}^{-} under a basic aqueous environment (with a negligible hydronium concentration.)

\begin{array}{cccccccc} \text{R} & \text{Ac}^{-}(aq) &+ & \text{H}_2\text{O}(aq) & \leftrightharpoons & \text{HAc}(aq) & + & \text{OH}^{-} (aq)\\ \text{I} & 0.10 \; \text{M} & & & & & &0.30 \; \text{M}\\ \text{C} & -x \; \text{M}& & & & +x \; \text{M}& & +x \; \text{M} \\ \text{E} & (0.10 - x) \; \text{M} & & & & x \; \text{M} & & (0.30 +x) \; \text{M} \end{array}

The question supplied the <em>acid</em> dissociation constant pK_afor acetic acid \text{HAc}; however, calculating the hydrolysis equilibrium taking place in this basic mixture requires the <em>base</em> dissociation constant pK_b for its conjugate base, \text{Ac}^{-}. The following relationship relates the two quantities:

pK_{b} (\text{Ac}^{-}) = pK_{w} - pK_{a}( \text{HAc})

... where the water self-ionization constant pK_w \approx 14 under standard conditions. Thus pK_{b} (\text{Ac}^{-}) = 14 - 4.7 = 9.3. By the definition of pK_b:

[\text{HAc} (aq)] \cdot [\text{OH}^{-} (aq)] / [\text{Ac}^{-} (aq) ] = K_b =  10^{-pK_{b}}

x \cdot (0.3 + x) / (0.1 - x) = 10^{-9.3}

x = 1.67 \times 10^{-10} \; \text{M} \approx 0 \; \text{M}

[\text{OH}^{-}] = 0.30 +x \approx 0.30 \; \text{M}

pH = pK_{w} - pOH = 14 + \text{log}_{10}[\text{OH}^{-}] = 14 + \text{log}_{10}{0.30} = 13.5

You might be interested in
Hello..................<br><br>.....​
VashaNatasha [74]

Hello.....

Have a beautiful and joyful day ahead.

3 0
2 years ago
How is the atomic mass of an element calculated? A. by determining the number of electrons in the outer orbital B.by determining
Vaselesa [24]

By adding together the number of protons and neutrons and multiplying by 1 amu, you can calculate the mass of the atom.

7 0
3 years ago
Read 2 more answers
How is a pair of molecular orbitals formed?
Montano1993 [528]
When two atoms combine, the overlap of their atomic orbitals produces molecular orbitals. 
3 0
4 years ago
Read 2 more answers
Transferring or sharing electrons between atoms forms
Brums [2.3K]
Transferring or sharing electrons between atoms forms a covalent bond.<span> Covalent bonding is when atoms share electrons. It is a chemical bond that involves the sharing of electron pairs. These pairs are called bonding pairs. Examples of compounds that has covalent bonds are CO2, organic compounds, lipids and proteins.</span>

6 0
3 years ago
Calculate the volume of a 1.25 M solution of HCN made from 31 grams of HCN
fenix001 [56]

Answer:

V HCNsln = 0.9176 L

Explanation:

V HCNsln = ?

∴ m HCN = 31 g

∴ <em>C</em> HCNsln = 1.25 mol/L

∴ molar mass HCN = 27.0253 g/mol

⇒ V HCNsln = (31 g)*(mol/27.0253 g)*(L/1.25 mol) = 0.9176 Lsln

5 0
3 years ago
Other questions:
  • What is the possible formula of a compound formed when sodium and chlorine bond
    9·1 answer
  • The volume of a gas is 36.0 ml at 10.0°c and 4.50 atm. at what temperature (°c) will the gas have a pressure of 3.50 atm and a v
    7·1 answer
  • Which radioisotopes have the same decay mode and have half-lives greater than
    5·2 answers
  • A baker uses sodium hydrogen carbonate (baking soda) as the leavening agent in a banana-nut quick bread. the baking soda decompo
    8·1 answer
  • Which of the following functional groups acts most like an acid in water? A) carboxyl B) amino C) carbonyl D) hydroxyl.
    9·1 answer
  • Which of the following is a reactant in photosynthesis?
    7·1 answer
  • What are examples of a Theory ?
    11·1 answer
  • Describe the process to electroplating with the help of an activity <br>​
    12·1 answer
  • In water, Vanillin, C8H8O3, has a solubility of 0.070 moles of vanillin per liter of solution at 25C. What will be produced if 5
    12·1 answer
  • Determine the number of molecules in 3.79 kilograms of the fictional compound Cs7(Cr5O3)4. Include the units, but do not write t
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!