Organic Chemistry Answers

1.  You have 16.5g of oxalic acid, H₂C₂O₄.

1.  What amount is represented by 16.5g of oxalic acid?

Explain the chemical reactions carried out in terms of the functional groups and reaction conditions involved.

 Preparation of Aspirin – room temperature; H3PO4 catalyst

 Ester preparation – reflux

 Halogenoalkane - 

(i) For each reaction above, write a balanced displayed formula equation to show the functional groups involved. 

(ii) Write detailed mechanism where relevant.

Classify each of the following reactions?

1. Mg + HCL =MgCL₂+H₂

2.P₄O₁₀+C = P₄ + CO₂

3.AgNO₃ +NaBr = AgBr + NaNO₃

4.Ba(OH)₂+H₂SO₄ =BaSO₄+H₂O

5.CL₂+ KBr = Br₂+KCL

Explain the chemical reactions carried out in terms of the functional groups and reaction conditions involved.

 Preparation of Aspirin – room temperature; H3PO4 catalyst

 Ester preparation – reflux

 Halogenoalkane - 

(i) For each reaction above, write a balanced displayed formula equation to show the functional groups involved. 

(ii) Write detailed mechanism where relevant.

1. Which solution has the lowest pH?

A. 0.10 M HClO4

B. 0.10 M HClO

C. 0.10 M KOH

D. 0.10 M CH3NH2

2. Which solution has the highest pH?

A. 0.05 M Sr(OH)2

B. 0.10 M Sr(OH)2

C. 0.10 M NaOH

D. 0.15 M NaOH

3. What is the pH of 0.03 M acid solution? The Ka of the acid is 510-3?

A. 1.5

B. 1.9

C. 2.0

D. 2.3 

4. What is the pH of 0.10 M Ba(OH)2 solution?

A. 0.70

B. 1.00

C. 13.00

D. 13.30 

5. What is the [OH- ] of a solution with pH = 4.33?

A. 2.1104 M

B. 2.110-10 M

C. 4.7109 M

D. 4.710-5 M

6. A 0.025 M solution of compound X has pH = 2.15. Which of the following statements is true?

A. Compound X is a strong acid.

B. Compound X is a strong base.

C. Compound X is a weak acid.

D. Compound X is a weak base.

7. A base has % ionization of 0.3%. What is the pH of 0.05 M solution of the base?

A. 1.3

B. 3.8

C. 10.2

D. 12.7

Suppose we titrate 20mL of 0.100M HCHO₂ with 0.100M NaOH. Calculate the pH

1. Before any base is added

2. When half of the HCHO₂ has been neutralized

3. After a total of 15.0mL of base has been added.

Formic acid constant k_a =1.8 ×10^-4

Sometimes after obtaining a crude product we recrystallize it. What is meant by recrystallisazation and what is its purpose on the crude product?

CH3-CH2-C-C-CH2-CH3

Draw resonance contributors for the carbanion that would be formed if meta-chloro- nitrobenzene could react with hydroxide ion.

In titration of the mixture to a methyl orange end point with standard NaOH, why does none of the NaOH is neutralized by the NH₄Cl