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A 0.025 M solution of a weak base gave a pH of 7.94 What is the Ka value of the acid that is conjugate to this base?
Answer: KA = 3.3*10-4
At first calculate KB ,supposing that this is a monoprotic weak base (B-):
[OH-]=1.0*10-(14-7.94) = 1.0*10-(6.06) = 8.7*10-7 and cB = 0.025
This filled in, using KB = [OH-]2/ cB to get:
KB = [8.7*10-7]2 / 0.025 = 7.59*10-13 / 0.025 = 3.0*10-11
Finally get KA by using:
KA*KB = KW = 1.0*10-14 (in water, at room temperature)
this results in KA = 1.0*10-14 / 3.0*10-11 = 3.3*10-4
What else can I help you with?
What happens to the buffer solution pH 7 when acid is added?
When acid is added to a buffer solution at pH 7, the pH of the buffer solution will decrease. However, due to the presence of a conjugate base in the buffer solution, the buffer will resist the change in pH and try to maintain its original pH value. This is because the conjugate base will react with the acid and prevent a significant decrease in pH.
How to represent the buffer solution?
In general, a buffer system can be represented by writing a salt followed by slash and an acid or conjugate base followed by slash and an acid like salt/acid or conjugate base/acid. Thus, the sodium acetate-acetic acid buffer system can be written asCH3COONa/ CH3COOH or CH3COO-/CH3COOHSimilarly, ammonia-ammonium chloride buffer system can be represented asNH3 / NH4+Note that NH4+ is an acid and NH3 is a conjugate base according to Lewry-Bronsted concept.
How do you determine if a unknown is a buffer or not?
To determine if a solution is a buffer, check if it contains a weak acid and its conjugate base, or a weak base and its conjugate acid. Alternatively, you can test the solution's pH - buffers resist significant changes in pH when small amounts of acid or base are added.
How you classify the solution as a best buffer solution?
A buffer solution is one involving a weak base/weak acid with its conjugate acid/base. In a buffer solution, the pH must be changed to only a small amount. Thus, any solution with a STRONG acid or a STRONG base is not a successful buffer solution because there would be a relatively large change in the initial pH.
What is a buffer reaction?
A buffer reaction is a chemical reaction involving a buffer solution, which resists changes in pH when an acid or base is added. Buffer solutions contain a weak acid and its conjugate base, or a weak base and its conjugate acid, to help maintain the pH of the solution within a specific range.
What two components make up a buffered solution?
A buffered solution is made up of a weak acid and its conjugate base (or a weak base and its conjugate acid). These components work together to maintain the pH of the solution by resisting changes in acidity or basicity when small amounts of acids or bases are added.
What is the conjugates for perchloric acid?
Perchloric acid has only a conjugate base, and it is chlorate(VII) ion.
What is known as a buffer in science?
A Buffer Is a Solution Containing a weak Acid and its conjugate base Ex. HC2H3O2 acetic acid and its conjugate base the acetate Ion C2H3O2 with a minus 1 charge. Buffer solutions resist changes to pH Because as acid is added the conjugate base in the solution reacts with the acid to neutralize it. The same is true for weak bases and and their conjugate acid.
What happens to the buffer solution pH 7 when acid is added?
When acid is added to a buffer solution at pH 7, the pH of the buffer solution will decrease. However, due to the presence of a conjugate base in the buffer solution, the buffer will resist the change in pH and try to maintain its original pH value. This is because the conjugate base will react with the acid and prevent a significant decrease in pH.
How to represent the buffer solution?
In general, a buffer system can be represented by writing a salt followed by slash and an acid or conjugate base followed by slash and an acid like salt/acid or conjugate base/acid. Thus, the sodium acetate-acetic acid buffer system can be written asCH3COONa/ CH3COOH or CH3COO-/CH3COOHSimilarly, ammonia-ammonium chloride buffer system can be represented asNH3 / NH4+Note that NH4+ is an acid and NH3 is a conjugate base according to Lewry-Bronsted concept.
Why does a solution of a conjugate acid base pair behave as a buffered solution?
The resist pH change in the following way: If you add a strong acid to the buffer solution, the conjugate base gets protonated, but the pH is not significantly changed. If you add a strong base to the buffer, the conjugate acid gets deprotonated, and again the pH is not changed very much. If you only had one component (let's say just the conjugate base), then it would not be able to resist change in pH if you added a strong base to the solution (although it would still counteract the affect of added acid).
How do you prepare a buffer solution?
To prepare a buffer solution, mix a weak acid and its conjugate base or a weak base and its conjugate acid in a specific ratio. This helps maintain a stable pH when small amounts of acid or base are added.
How can one determine the acid dissociation constant (Ka) from the concentration of a solution?
To determine the acid dissociation constant (Ka) from the concentration of a solution, you can measure the concentrations of the acid, its conjugate base, and the equilibrium concentrations of both in the solution. By using these values in the equilibrium expression for the acid dissociation reaction, you can calculate the Ka value.
Can you determine whether each combination of substances can be used to create a buffer?
Yes, the ability to create a buffer solution depends on the combination of substances used. Buffers are typically made by combining a weak acid with its conjugate base, or a weak base with its conjugate acid. The presence of both a weak acid and its conjugate base, or a weak base and its conjugate acid, allows the solution to resist changes in pH when an acid or base is added.
How do you make a buffer solution?
To make a buffer solution, mix a weak acid and its conjugate base or a weak base and its conjugate acid in a specific ratio. This helps maintain a stable pH level when small amounts of acid or base are added.
How can one determine a buffer solution?
A buffer solution can be determined by mixing a weak acid with its conjugate base, or a weak base with its conjugate acid. This combination helps maintain a stable pH level when small amounts of acid or base are added.
What is a buffer solution made up of?
An acid base conjugate pair
