Question: Methylamine, CH 3 NH 2 , is a weak base used as a building block for some pharmaceuticals. If you prepare an aqueous solution of

Methylamine, CH₃NH₂, is a weak base used as a building block for some pharmaceuticals. If you prepare an aqueous solution of methylamine for use in a synthesis, you might need to know its pH to avoid unwanted side reactions. Calculate the pH and percentage protonation of a 0.20 m aqueous solution of methylamine at 25°C. The K_b for CH₃NH₂ is 3.6 * 10^–4.

ANTICIPATE Because methylamine is a weak base (like all amines), you should expect pH > 7 and only a small percentage protonation.

PLAN Proceed as in Toolbox 6D.2. Toolbox 6D.2 HOW TO CALCULATE THE PH OF A SOLUTION OF A WEAK BASE CONCEPTUAL BASIS Proton transfer

Write the concentration changes that are needed for protonation of B to reach equilibrium. Assume that the

Toolbox 6D.2 HOW TO CALCULATE THE PH OF A SOLUTION OF A WEAK BASE CONCEPTUAL BASIS Proton transfer equilibrium is established as soon as a weak base is dissolved in water, and so the hydroxide ion concentration can be calculated from the initial concentration of the base and the value of its basicity constant. Because the hydroxide ions are in equilibrium with the hydronium ions, the values of pOH and pKw can be used to calculate the pH. PROCEDURE Step 1 Write the chemical equation and the expression for K for the proton transfer equilibrium. Set up a table with columns labeled by the base (B), the conjugate acid of the base (HB*), and OH. In the first row below the headings, show the initial concentration of each species. For this step, assume that no base molecules have been protonated.

Step by Step Solution

★★★★★

3.47 Rating (163 Votes )

There are 3 Steps involved in it

1 Expert Approved Answer

Step: 1 Unlock

Step 1 Write the proton transfer equilibrium and the corresponding equilibrium table with all concen... View full answer

Question Has Been Solved by an Expert!

Get step-by-step solutions from verified subject matter experts

Step: 2 Unlock

Step: 3 Unlock

Students Have Also Explored These Related Chemical Principles Questions!

Determine the normal force, shear force, and moment at points C and D in the beam. 300 lb/ft -12 ft C 15 ft- B D 3 ft 6 ft 6000 lb-ft

For the matrix game of Problem 31, would you rather be player R or player C? Explain. Data from problem 31 In Problem for each matrix game that is strictly determined (if it is not strictly...

Let X be a random variable representing the time between successive arrivals at a checkout counter in a supermarket. The values of X in minutes (rounded to the nearest minute) are Assume that the pdf...

You are working in the emergency room of a hospital where a patient suffering from influenza has developed metabolic alkalosis, a condition in which the pH of the blood is too high. You have...

K=1.38100.10 Mydlo 0 :0 00 IT EN-C-H 11 HH pk, carboxylic acid = 2.34 pk, protonated amine 9.6 15. One form of the amino acid glycine is shown above. At which would this be the predominant form of...

Answer all questions completely(Table 1, 2, 3): Page 1 > of 19 ZOOM Experiment1 Chemical Reactions and Net Lonic Equations I. Objective: To predict the products of some displacement reactions and...

22 R e a d i n g t h e T e a L e a v e s a t T e a a n d M o r e : Re s o l v i n g C o m p l e x Su p p l y Ch a i n Issues 1 Abstract Tea and More is facing growing pains from its rapid expansion...

By MARK@ (Ruska, Markevichus, Naniev, Grachev) Emerging russian ice-cream market is good area for different producers as it has great potential 1. Currently Russian ice-cream market is the 4th...

Summary this parts17.1 and 17.2 in this lesson and give one Case study with this lesson. 548 Lext 17 Leadership, Organization, 7 and Corporate Social Responsibility LEARNING OBJECTIVES the companies...

Experiments for General Organic and BiochemistryBettelheim/Landesberg 6 EXPERIMENT Properties of Carboxylic Acids and Esters BACKGROUND Carboxylic acids are structurally like aldehydes and ketones in...

For this assignment, you will write a case analysis. You have a choice of using Case 27 in your textbook, 3M - The First 110 Years, or choosing a case from the list below. Then, write a comprehensive...

Consider the problem of a man who has recently earned his Ph.D. and is being interviewed for three jobs. His goal is an overall job satisfaction. He is considering the following criteria: Research,...

What are some key considerations that could drive organizations to put metrics in place to measure the effectiveness of internal communication initiatives? How might the metrics be similar or...

4. The owner of a new business recently questioned the accountant about the value of having both a journal and a ledger. The owner believes that it is a waste of effort to enter data about...

Which of the following statements is not correct? (a) A ratio reflects a business model relationship between two or more variables. (b) When using comparative ratio analysis, it is important to...

In our discussion of blackbody radiation, the average energy of an oscillator E osc = hv/(e hv/kBT 1) was approximated as E osc = hv/[(1 + hv/k B T) 1] = k B for hv/k B T

Using the root mean square speed, v rms = (v 2 ) 1/2 = 3k B T/m, calculate the gas temperatures of He and Ar for which = 0.25 nm, a typical value needed to resolve diffraction from the surface of a...

Electrons have been used to determine molecular structure by diffraction. Calculate the speed and kinetic energy of an electron for which the wavelength is equal to a typical bond length, namely,...

Describe the significance of a national treasury in the public sector

Name a specific type of business in your opening statement and what the business does. Identify how this company uses the Internet to do an everyday activity to run the business. Explain how it was...

Discuss the four principal purposes of the required communication with the audit committee regarding certain additional information obtained during the audit.