4) Aniline, a weak base, reacts with water according to the reaction represented above.
a) Write the equilibrium constant expression, Kb, for the reaction represented above.
b) A sample of aniline is dissolved in water to produce 25.0mL of a 0.10M solution. The pH of the solution is 8.82. Calculate the equilibrium constsant, Kb, for this reaction.
*Note I have already figured out A and B to this problem...I just wanted to give it to you because the others build off of it. I do not understand how to calculate the pH, especially at the equivalence pt.
c)The solution prepared in part (b) is titrated with 0.10 m HCl. Calculate the pH of the solution when 5.0 mL of the acid has been added.
d) Calcuate the pH at the equivalence point in the titration in part (c).
e) The pKa values for the several indicator are given below. Which of the indicators listed is most suitable for this titration? Justify your answer.
Acids, bases and indicators are explained.
Azo Dyes, Acid-Base Indicator and Ferrocene
1. What is the main structural feature of the azo dyes that causes them to be colored compounds?
2. Methyl Orange is an acid-base indicator. In dilute solution at pH greater than 4.4, it is yellow. At pH = 3.2 the solution appears red. Draw a structure of the species that is formed at the lower pH of the acid proton adds to the azo nitrogen atom adjacent to the aromatic ring containing the -SO3 group. Why does the proton add to this particular nitrogen when two other nitrogen atoms are available in the molecule?
3. In the formation of diacetylferrocene, the product is always the one in which each ring is monoacetylated. Why is no diacetylferrocene produced in which both acetyl groups are on the same aromatic ring?
4. Ferrocene cannot be nitrated using the conventional HNO3-HzSO4 mixed acid conditions, even though nitration is an electrophilic aromatic substitution reaction. Explain.View Full Posting Details