Which combination is the best choice to prepare a buffer with a ph of 9.0? which combination is the best choice to prepare a buffer with a of 9.0? nh3; nh4cl (pkb for nh3 is 4.75) hcho2; nacho2 (pka for hcho2 is 3.74) c5h5n; c5h5nhcl (pkb for c5h5n is 8.76) hno2;nano2 (pka for hno2 is 3.33)?
Answers
Answer:
Explanation:
The best choice to prepare a buffer of pH 9.0 is a conjugate acid/base pair in which the acid has pKₐ = 9.0 ± 1.
Let's examine each of the choices.
A. NH₃/NH₄Cl
For NH₃, = pK_b = 4.75
For NH₄⁺, pKₐ 14.00 - 4.75 = 9.25
B. HCHO₂/NaCHO₂
For HCHO₂, pKₐ = 3.74
C. C₅H₅N/ C₅H₅NHCl
For C₅H₅N, = pK_b = 8.76
For C₅H₅N⁺, pKₐ 14.00 – 8.76 = 5.21
D. HNO₂/NaNO₂
For HNO₂, pKₐ = 3.33
The only acid with a pKₐ close to 9.0 is the ammonium ion.
The best buffer to prepare a buffer with pH 9.0 is
From the given options, the best combination to prepare a buffer with a PH of 9.0 is given by;
Option 1; NH₃;NH₄Cl
- A buffer solution is defined as an aqueous solution that consists of a mixture of a weak acid and its conjugate base or mixture of a weak base and its' conjugate acid.
Now, we want to find the best choice to prepare a buffer of pH 9.0. Thus, let us look at each option;
Option 1; NH₃;NH₄Cl
We are given that pK_b for NH₃ is 4.75
Thus pKₐ for NH₄ is;
NH₄; pKₐ = 14.00 - 4.75
NH₄; pKₐ = 9.25
Option 2; HCHO₂; NaCHO₂
We are given that pK_a for HCHO₂ is 3.74
HCHO₂; pKₐ = 3.74
Option 3;C₅H₅N; C₅H₅NHCl
We are given that pK_b for C₅H₅N is 8.76
Thus
For C₅H₅N, = pK_b = 8.76
Thus, pKₐ for C₅H₅N is;
C₅H₅N; pKₐ = 14.00 – 8.76
C₅H₅N; pKₐ = 5.21
Option 4; HNO₂;NaNO₂
We are given pKₐ for HNO₂ as 3.33
HNO₂; pKₐ = 3.33
Looking at all the pKₐ values, the only acid that has a pKₐ close to 9.0 is NH₄ with a pKₐ of 9.25.
In conclusion, the best combination to prepare a buffer with pH of 9.0 is
NH₃;NH₄Cl
Read more at; brainly.com/question/15592723
Related Questions
If the atomic radius of a calcium crystal is 180 pm, what is the length of the edge of the unit cell? (the calcium crystal forms
a mixture of oxygen, hydrogen, and nitrogen gases exerts a total pressure of 282 kpa. if the partial pressures of oxygen and hydrogen are 110 kpa and 106 kpa respectively, what is the partial pressure exerted by nitrogen?
Which of the following is a extensive property of a bubble of air ? A. Temperature B. Radius C. Density D. Percent oxygen
You pour a spoonful of salt into a glass of water. Explain what happens to the mass of the salt and the mass of the water.
a. True
b. False
Answers
Answer: False (b)
Explanation: No two elements can have the same spectrum.
Answers
the known density of the liquid is
the density of a liquid
Thus, experimental error of 0.0108 g /mL is present.
Thus, Percentage error of 7.31 % is present.
B The volume increases to fill the new container, but the shape stays the same.
C The volume stays the same, but the shape changes to fit the new container.
D The volume and the shape change to fill the new container.
2 Which of these correctly defines the pH of a solution?
A the negative log of the hydronium ion concentration
B the log of the hydronium ion concentration
C the negative log of the hydroxide ion concentration
D the log of the hydroxide ion concentration
Answers
Answer 1 : The correct option is C.
Explanation :
The property of liquid is, they have fixed volume but do not have fixed shape. when a liquid is transferred from one container to another then the volume remains the same, but the shape changes according to the shape of the container.
Answer 2 : The correct option is A.
Explanation :
pH : It is defined as the negative logarithm of the hydronium ion concentration.
The expression of pH is,
2) A
I just took the quiz
Hope this helps you and others in the future!
B. liquids.
C. solids.
D. fluids.
E. none of the above
Answers
Final answer:
Convection is the transfer of heat in a fluid (which can be a liquid or gas) through the movement of its particles. A fluid near a heat source will get heated, causing it to rise and exchange place with the cooler, denser fluid.
Explanation:
Energy transfer by convection is primarily restricted to both liquids and gases, which are both classified as fluids. Hence, the correct answer is D. Fluids.
Convection refers to heat transfer in a gas or liquid by the circulation of currents from one region to another. This happens when a fluid near a heat source gets heated, its particles move faster and spread apart, causing the fluid to become less dense. As a result, the warmer, less dense fluid rises, and the cooler, denser fluid sinks. The continuous movement of fluid in this way creates what we call a convection current, which results in the transfer of energy.
Learn more about Energy Transfer by Convection here:
#SPJ6
Answers
(2) increases
(3) remains the same
Answers
Answer:
Hence the correct answer is remains the same
Explanation:
As a Ca atom undergoes oxidation to Ca2+,as follows:
Ca --- Ca 2+ + 2e-
In the process of oxidation calcium loss 2 electron only there is no change in the number of protons as well neutrons therefore there is no change in the number of neutrons in its nucleus
Hence the correct answer is remains the same
Oxidation:
Oxidation is a process in which either 1 or all following changes occurs:
1. Gaining of oxygen atoms
2. Loss of electrons
3. Loss of hydrogen atom.
4. Increasing oxidation number.
Reduction:
Reduction is a process in which either 1 or all following changes occurs:
1. Loss of oxygen atoms
2. Gaining of electrons
3. Gaining of hydrogen atom.
4. Decreasing oxidation number.