DIBASIC ACIDS.

1216. Write the formulæ of oxalic acid and its homologues up to adipic acid.

1217. How may oxalic acid be obtained starting with cyanogen and vice versâ? How may it be obtained starting with carbon dioxide?

1218. Give reactions (other than those referred to above) for preparing oxalic acid, and give a full account of the method adopted on the large scale.

1219. What is the action on oxalic acid of (a) heat, (b) potassium permanganate, (c) sulphuric acid, (d) potassium hydrate? Give equations.

1220. One hundred cubic centimetres of a solution of potassium permanganate are required to saturate a solution of o'0396 gramme iron. How much of this solution is needed to decompose completely o'873 gramme crystallized oxalic acid?

1221. How much carbon dioxide by volume and weight

should be given off by treating 6·789 grammes oxalic acid with potassium permanganate?

1222. State fully what occurs when a solution of potassium permanganate is added to one of oxalic acid alone, and in presence of sulphuric acid.

1223. How much carbon dioxide and monoxide can be obtained from the oxalic acid required to neutralize 19 grammes of caustic soda ?

1224. How many series of salts does oxalic acid form? Give examples of each with formulæ.

1225. Give the formula for each of the following bodies and explain how they are related to oxalic acid: (a) oxamide, (b) oxamic acid, (c) glyoxal, (d) glyoxylic acid, (e) glycollic acid.

1226. How may succinic acid be prepared (a) syntheti cally, (b) from malic acid?

1227. How may succinic acid be obtained starting with acetic acid and vice versâ?

1228. What is the action of hydriodic acid on tartaric acid?

1229. By what reaction can it be proved that succinic acid contains ethylene, and how may ethylene be obtained from it?

1230. How is tartaric acid prepared, and what is the action on it of (a) oxidizing agents, (b) caustic potash?

1231. What is the formula of tartar emetic? What percentage of carbon does it contain?

1232. Describe the isomeric modifications of tartaric acid.

TRIBASIC ACIDS.

1233. Give a short account of the natural occurrence of citric acid, and describe how the acid is manufactured. 1234. What different products are obtained by heating citric acid?

1235. What is tricarballylic acid, and how is it related to citric acid?

1236. If 0 276 gramme of citric acid were used in an organic analysis, what weight of carbon dioxide and of water should be obtained?

1237. What is the action of chlorine on citric acid?

1238. By what reactions is citric acid recognised and distinguished from tartaric acid?

BENZOL AND ITS DERIVATIVES.

1239. How has benzol been prepared synthetically? 1240. How is benzol obtained from coal-tar? How is it purified?

1241. 7892 grammes of benzoic acid are heated with excess of lime. What reaction occurs, and how much

of the product is obtained?

1242. What products are obtained by passing alcohol vapour through a red-hot tube?

1243. How would you ascertain the presence of benzol vapour in coal-gas?

1244. Draw the graphic formula of benzol.

1245. What is the action on benzol of (a) sulphuric acid, (¿) nitric acid, (c) bromine ?

1246. What is aniline? How is it prepared and purified? What is the action of hydrochloric acid on aniline?

1247. What is toluidine, and how is it related to aniline?