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SUBJECT XI. ORGANIC CHEMISTRY.

EXAMINERS, PROFESSOR ROSCOE, B.A., PH.D., LL.D., F.R.S., AND W. J. RUSSELL, Esa., PH.D., F.R.S.

GENERAL INSTRUCTIONS.

If the rules are not attended to, the paper will be cancelled.

You may take the Elementary, or the Advanced, or the Honours paper, but you must confine yourself to one of them.

Put the number of the question before your answer.

Whenever possible, you are to express the reactions by equations. You are to give such numerical details as will show the mode of calculation.

The value attached to each question is indicated by a number placed at the end of the question, but a full and correct answer to an easy question will in all cases secure a larger number of marks than an incomplete or inexact answer to a more difficult one.

You are to confine your answers strictly to the questions proposed. Your name is not given to the Examiners, and you are forbidden to write to them about your answers.

The examination in this subject lasts for three hours.

First Stage or Elementary Examination.

INSTRUCTIONS

You are only permitted to attempt eight attempt question I and either question 4 or 6.

You must

questions. With these exceptions, you may select the questions from any part of the Elementary paper.

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1. How many litres of oxygen are required for the complete combustion of 15 grams of methyl alcohol? What volume of carbon dioxide will be formed?

(14.)

2. Hydrocyanic acid is added to caustic potash, to carbonate of potash to mercuric oxide. Give equations of the actions, if any, which occur. How would you distinguish cyanide of silver from chloride

of silver?

3. How can oxalic acid be prepared from carbon dioxide?

(12.)

(12.)

4. Describe two methods for preparing ordinary ether. How would you ascertain whether the product be perfectly pure?

(12.)

5. The per-centage composition of a body is this:

Carbon
Hydrogen
Oxygen

State how you would deduce from these numbers a formula for the

54 55

9.09

36.36

100.00

body, explaining fully each step in the process.

(13.)

6. Quote several examples which show that ethyl alcohol is the analogue of caustic soda. (12.) 7. What organic compounds can be obtained by the action of sulphuric acid on alcohol? How can you distinguish between them? (10.) 8. Quote reactions which justify the assumption that acetic acid is a methyl compound, i.e., that it contains the radical CH3? (12.) 9. How can ethyl alcohol be converted into acetic acid? Point out the principal points of resemblance and of difference between acetic and formic acids. (12.) 10. If nitric acid act on alcohol alone, ethyl nitrate is not formed, if the alcohol have a little urea dissolved in it, ethyl nitrate is formed how do you account for this? (9.) 11. How can formic acid be produced synthetically? How can it be prepared from oxalic acid? If the pure acid be heated with sulphuric acid what happens?

(12.) 12. How would you obtain ethane (ethyl hydride) from ethyl iodide? What bulk of this gas measured at 0° and 760mm could be obtained from 10 grams of ethyl iodide?

(13.)

Second Stage or Advanced Examination.

INSTRUCTIONS.

Read the General Instructions at the head of the Elementary paper. You are only permitted to attempt eight questions.

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21. The amount of nitrogen in an organic body may be determined either by converting it into animonia or by measuring it as nitrogen gas; describe, with sketches of the apparatus, these two methods. Name some bodies that can only be analysed by the second method.

(10.)

(10.)

22. What are the characteristic properties of an alcohol? 23. You are required to prepare ethyl iodide, and afterwards to test accurately the purity of the product; how would you do it? (10.) 24. Give equations showing the changes involved in the production of aniline from benzene. From what other source can aniline be obtained, and by what tests would you recognise its presence in an aqueous solution?

(13.)

25. Starting from zinc ethyl, describe how you would obtain from it propionic acid ? (14.) 26. From what natural sources are morphine, quinine, and strychnine obtained? Describe the nature and characteristic chemical properties of these bodies, and state how they can be distinguished from one another.

(10.)

27. It is now generally assumed by chemists that the six carbon atoms in benzene are united in a closed chain or ring, state the main facts upon which this conclusion is based, and briefly recapitulate the line of argument. (15.) 28. How can glycol be obtained from ethylene? What are the products of the oxidation of glycol ? (12.) 29. Describe two methods by which you can pass from the ethyl to the propyl series. (11.) 30. 0 571 grams of a monobasic acid gave on combustion 1·4362 grams of carbon dioxide and 0.2547 grams of water; 0.2143 grams of the silver salt of this acid gave 0 101 grams of silver. Give the formula and the per-centage composition of the acid. (15.)

Honours Examination.

INSTRUCTIONS.

Read the General Instructions at the head of the Elementary paper. You are permitted to attempt six questions.

41. Calculate the vapour density of a compound from the following data:

A. Victor Meyer's method.

Barometer

Weight of substance used 0.0585 grams. Volume of air
expelled 9.8 cbc. Temperature 16°C.
732.7mm

B. Hofmann's method.

Weight of substance used 0·1366 grams. Volume of vapour 101.9 cbc. Temperature of vapour 140°C. Height of mercury column 503 5mm. Barometer 730.9mm at temperature of 24.7°C.

The co-efficient expansion of mercury is 0.00018. 42. Describe the method employed by Horbaczewski for the artificial production of uric acid, and point out the importance of this synthesis.

43. What is the nature of the experimental proof that the compounds formed by the action of the moniodo-paraffins on silver nitrite are true nitro-derivatives. Give an account of the preparation and properties of the nitro-paraffins.

44. How may salicylic aldehyde be prepared from phenol?

45. Describe the acids isomeric with tartaric acid, stating how they are obtained, and how they are distinguished from one another.

46. How many paraffins containing 5 atoms of carbon, and how many alcohols derived from them can exist, according to theory; how many of them have been actually prepared?

47. Describe Skraup's method of preparing quinoline and quinoline derivatives.

48. When phenol is dissolved in aniline, a crystalline product is obtained; supposing this to consist of a compound of the above substances, how would you ascertain by experiment their relative proportion?

SUBJECT XIP. PRACTICAL ORGANIC
CHEMISTRY.

EXAMINERS, PROFESSOR ROSCOE, B.A., PH.D., LL.D., F.R.S., AND W. J. RUSSELL, Esq., PH.D., F.R.S.

GENERAL INSTRUCTIONS.

If the rules are not attended to, the paper will be cancelled.

You must take the same stage in this written examination that you have already taken in the examination in Practical Analysis in this subject.

Put the number of the question before your answer.

The value attached to each question is indicated by a number placed at the end of the question.

You are to confine your answers strictly to the questions proposed. Your name is not given to the Examiners, and you are forbidden_to write to them about your answers.

The examination in this paper lasts for one hour.

First Stage or Elementary Examination.

INSTRUCTIONS.

You are only permitted to attempt two questions.

1. A sample of chloroform is given you; describe fully how you would demonstrate that carbon, hydrogen, and chlorine are contained in this body.

(10.) 2. Give the equations for the reactions which you would employ to recognise the presence of the hydrocyanic acid in a solution of potassic cyanide, of the oxalic acid in a solution of ammonium oxalate, and of the formic acid in a solution of potassic formate, (15.) 3. How would you show by experiment that a sample of beer contains alcohol ? (10.)

Second Stage or Advanced Examination.
INSTRUCTIONS.

Read the General Instructions at the head of the Elementary paper.
You are only permitted to attempt two questions.

21. Describe how you would determine the boiling point of a liquid. What is meant by fractional distillation? How is it carried out?

22. Give the equations for the reactions by which you would identify oxalic acid.

(10)

23. How would you prove the presence of ethyl alcohol in a very dilute aqueous solution?

(10.)

Honours Examination.

INSTRUCTIONS.

Read the General Instructions at the head of the Elementary paper. You are expected to answer both the questions given.

1. Discuss the methods in use for the estimation of chlorine, bromine, and iodine in organic bodies.

2. Describe the principle of the methods, both chemical and optical, which are used for the determination of dextrose.

SUBJECT XIp. PRACTICAL ORGANIC
CHEMISTRY.

PRACTICAL EXAMINATION IN CHEMICAL ANALYSIS.

EXAMINERS, PROFESSOR ROSCOE, B.A., PH.D., LL.D., F.R.S., AND W. J. RUSSELL, Esq., PH.D., F.R.S.

Instructions to Candidates.

Analysis Tables and Works on Chemistry may NOT be used.

Elementary Stage.

The practical work for the Elementary Stage Examination is confined to the qualitative analysis of two mixtures, which may each contain not more than two of the following constituents :

Hydrocyanic acid, formic acid, acetic acid, oxalic acid, ethyl alcohol, formaldehyde.

Two hours are allowed for this analysis.

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