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TRIADS.

ANTIMONY.

932. How is antimony prepared from the sulphide, and what are the chief uses of the metal ?

933. How is amorphous antimony obtained, and what are its properties ?

934. Give different methods for the preparation of antimoniuretted hydrogen (stibine).

935. What happens when stibine is passed (a) into silver nitrate solution, (6) over sulphur exposed to light, (c) into solution of potassium permanganate, (d) through a red-hot tube ?

936. Give an equation to represent the action of stibine on sulphur, and state how the reaction was used to ascertain the composition of the gas.

937. Give all the reactions you know for distinguishing stibine from arsine.

938. How are the trichloride, pentachloride and oxychloride of antimony prepared ? What is the action of water on each ?

939. Compare the compounds of antimony with those of arsenic and phosphorus, and point out the analogies between them.

940. What is the composition of tartar emetic ? How is the salt prepared ?

941. How has the combining weight of antimony been determined ? What is the result of the most recent determinations?

942. What is the action of strong hydrochloric acid on antimony trisulphide, and of the products on each other? Give equations.

943. What volume of sulphuretted hydrogen at N.T.P. is required to precipitate completely 789 grammes of tartar emetic ?

BISMUTH.

944. How is bismuth obtained in well-defined crystals, and what is its crystalline form?

945. Describe the liquation process for obtaining bismuth, and also the process by reduction with iron.

946. What are the constituents of “fusible metal”? At what temperature does it melt, and what are its uses ?

947. What are the properties of bisinuth, and how is a solution of it most easily made?

948. Give equations for the reactions which when phosphorus, arsenic, antimony, bismuth, and tin are treated with nitric acid.

949. Suggest methods for preparing a compound of bismuth with hydrogen.

950. Give two methods for obtaining bismuth chloride. What is its formulæ, and what is its action on water ?

951. What are the most characteristic tests for bismuth salts? How could you distinguish the oxychlorides of bismuth and antimony ?

Occur

L

GOLD.

952. Give a short account of the natural occurrence and distribution of gold.

953. How is the quantity of gold in auriferous minerals, and in gold bullion ascertained ?

954. Describe how gold is extracted (a) by placer mining, (6) by vein mining, (c) by hydraulic mining.

955. Give a short account of Plattner's chlorination process for the extraction of gold.

956. How is gold separated from silver and copper by "parting"?

957. How may gold be refined by means of chlorine?

958. How may a solution of gold be obtained ? Name any reagents which precipitate metallic gold from the chloride.

959. What are the properties of gold ? State the action of acids and alkalies on it, and how the oxides of gold are obtained.

TETRADS.

TIN.

960. From what ore is tin invariably prepared ? Describe the various processes employed in its extraction.

961. How is tin-plate made? What is the composition of the following alloys of tin ? (a) pewter, (b) solder, (c) gun-metal, (d) bronze, (e) speculum metal, Britannia metal.

962. Express by equations the action of nitric, hydrochloric and sulphuric acids on tin.

963. How are each of the chlorides of tin prepared ? Why does stannous chloride solution become turbid after exposure to air, and how may this be prevented ? 964. What occurs when zinc is added to

an acid solution of stannous chloride ? What is the action of stannous chloride on mercuric chloride and on ferric chloride?

965. What is the constitution of stannic and of metastannic acids, and how is sodium stannate prepared ?

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