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799. How does lithium occur in nature?
what sources, and how, are the lithium compounds
800. How is the metal obtained, and what are its properties? Give reasons for classing it with the
801. How much lithium by bulk would weigh the same as I c.c. of platinum?
802. By what reactions is lithium distinguished from potassium and sodium? How could small quantities of lithium salts be detected in a mineral water?
803. Mention the chief natural sources of sodium compounds. How is the metal prepared on the large scale, and what is it chiefly used for?
S04. Give a full account of Leblanc's process for the preparation of soda from common salt, and illustrate the changes which occur by equations.
805. What improvements on the original process of Leblanc have been recently introduced?
806. In practice 1,800 lbs. of salt (containing 2'4 per cent. of impurities) are treated with 1,800 lbs. of vitriol having a specific gravity of 1°42 (= 52.8 per cent. H2SO) for the preparation of salt-cake. Find how much hydrochloric acid and sodium sulphate should theoretically be obtained from these quantities of material.
807. For the preparation of black ash, 224 lbs. each of salt-cake and limestone are fused with 140 lbs. coal. What quantities are theoretically required for this weight of salt-cake?
808. What are the chief constituents of commercial salt-cake, black ash soda ash, and caustic soda?
809. How are each of the substances mentioned in the previous question analysed?
810. What is “vat waste,” and what useful products may be obtained from it?
811. Describe Mond's process for the recovery of sulphur from vat waste, and state the principles involved in the process.
812. Describe Hargreaves' process for the manufacture of salt-cake without the use of sulphuric acid.
813. How is black ash treated so as to obtain (a) soda ash, (b) caustic soda, (c) soda crystals (crystallized sodium carbonate)?
814. How is sodium bicarbonate prepared on the large scale? Is its reaction alkaline, acid, or neutral? Why is it called an acid salt, and what occurs when it is heated?
815. How would you make a complete quantitative analysis of (a) salt-cake, (b) soda ash, (c) caustic soda?
816. Describe the process called the ammonia-soda process, and give the reactions on which it depends.
817. Describe the various methods in use for obtaining common salt from (a) sea-water, (b) brine springs, (c) salt beds.
818. How is perfectly pure caustic soda obtained? What are the chief impurities in the commercial product?
819. By what reactions are the sodium compounds usually recognised? Name any insoluble sodium salts.
820. What are the chief natural sources of the potassium compounds? Suggest a process for obtaining potash from felspar.
821. Describe the various methods of Davy, Gay Lussac and Thenard, and Matthiessen, for the preparation of potassium, and state how it is now obtained on the large scale.
822. How did Dittmar and Dewar determine the vapour density of potassium, and what was the result? 823. How may caustic potash be obtained perfectly pure?
824. How is potassium chlorate prepared on the large scale?
825. How is the presence of potassium nitrate in the soil in certain parts of India accounted for?
826. Describe the process for the artificial preparation of nitre. By whom and under what circumstances was it introduced?
827. Describe the experiments of Schlesing and