What are the concentrations of HA and A- at this point in concentration?

In summary, the concentrations of HA and A- at this point in concentration can be found by first calculating the concentration of the weak acid using c=n/v, then finding the concentration of the strong base using the same formula. Using the equation for the ionization of water (Kw=[H+][OH-]), with Kw set at 10^-14 and the concentration of OH- calculated earlier, the concentration of H+ ions can be found, and from there, the concentrations of HA and A- can be determined.
  • #1
Complexity
14
0

Homework Statement



0.00116 moles of a weak monoprotic acid was dissolved in 25.0 mL in water. This solution was titrated with 10.0 mL of 0.0633 M NaOH. What are the concentrations of HA and A- at this point in concentration?


Homework Equations





The Attempt at a Solution

 
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  • #2
Complexity said:

Homework Statement



0.00116 moles of a weak monoprotic acid was dissolved in 25.0 mL in water. This solution was titrated with 10.0 mL of 0.0633 M NaOH. What are the concentrations of HA and A- at this point in concentration?


Homework Equations





The Attempt at a Solution


Where do I start?
 
  • #3
Reaction equation won't hurt.

You have to show your attempts at solving the question to receive help. This is a forum policy.
 
  • #4
Complexity said:

Homework Statement



0.00116 moles of a weak monoprotic acid was dissolved in 25.0 mL in water. This solution was titrated with 10.0 mL of 0.0633 M NaOH. What are the concentrations of HA and A- at this point in concentration?


Homework Equations





The Attempt at a Solution


Maybe you do it using Kw ...
Find the concentration of the weak acid using c= n/v where c is concentration, n is moles and v is volume...
then find the concentration of base using the same formula... since the base is strong , OH concentration is the same as the base itself.i.e.NaOH ...

Now use,
Kw = [H+] [OH-]
use Kw as 10^-14
and conc of OH u calculated earlier..
find conc of H+ ions...the rest is simple...
 
  • #5


At this point in concentration, the concentration of HA (the weak monoprotic acid) can be calculated by using the equation c1v1 = c2v2, where c1 is the initial concentration of the acid (0.00116 moles/0.025 L = 0.0464 M), v1 is the initial volume (25.0 mL), c2 is the final concentration (unknown), and v2 is the final volume (25.0 mL + 10.0 mL = 35.0 mL). Therefore, c2 = (c1v1)/v2 = (0.0464 M * 25.0 mL)/35.0 mL = 0.0333 M. This is the concentration of HA at this point in concentration.

To find the concentration of A-, we can use the equation c2v2 = c3v3, where c2 is the concentration of the acid (0.0333 M), v2 is the volume of acid used (10.0 mL), c3 is the concentration of the base (0.0633 M), and v3 is the volume of base used (10.0 mL). Therefore, c3 = (c2v2)/v3 = (0.0333 M * 10.0 mL)/10.0 mL = 0.0333 M. This is also the concentration of A- at this point in concentration.

In summary, at this point in concentration, the concentration of HA is 0.0333 M and the concentration of A- is also 0.0333 M.
 

FAQ: What are the concentrations of HA and A- at this point in concentration?

What are the concentrations of HA and A- at this point in concentration?

The concentrations of HA and A- at a given point in concentration depend on the initial concentration of HA, the equilibrium constant (K), and the extent of the reaction. They can be calculated using the Henderson-Hasselbalch equation: [A-] = [HA] * (K / [H+]).

How do I determine the equilibrium constant (K)?

The equilibrium constant (K) can be determined experimentally by measuring the concentrations of HA and A- at equilibrium and using the equation K = [A-] / [HA]. It can also be calculated from other known equilibrium constants using the equation K = K1 * K2 * K3 * ..., where K1, K2, K3, etc. are the equilibrium constants for each individual step in the reaction.

What is the Henderson-Hasselbalch equation?

The Henderson-Hasselbalch equation is an equation used to calculate the concentrations of a weak acid (HA) and its conjugate base (A-) at a given point in concentration. It takes into account the initial concentration of HA, the equilibrium constant (K), and the extent of the reaction.

Can the concentrations of HA and A- be calculated at any point in concentration?

Yes, the concentrations of HA and A- can be calculated at any point in concentration as long as the initial concentration of HA and the equilibrium constant (K) are known. However, the accuracy of the calculation may be affected by factors such as temperature, concentration changes, and the presence of other substances.

How do the concentrations of HA and A- affect the pH of the solution?

The concentrations of HA and A- directly affect the pH of the solution. A higher concentration of HA will result in a more acidic solution, while a higher concentration of A- will result in a more basic solution. This is due to the dissociation of HA into H+ ions and A- ions, which have opposite effects on the pH of the solution.

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