SOME CHEMICAL CONCEPTS 



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each, but the resulting properties be quite different. 

 Thus, Methyl Cyanide 



CH 3 CN or 



I 



H 



H C CEEN 

 H 



is a colourless liquid, possessing a strong but not 

 disagreeable smell, and is readily soluble in water. 

 Methyl Isocyanide, however 



CHUNG or 



H 



H 



-N=C 



is also a colourless liquid, possessing, as Perkin and 

 Kipping state without exaggeration, an almost 

 unbearable odour and poisonous properties. 



It is extremely important, and also rather difficult, 

 to get a clear appreciation of what is meant by 

 the terms acid, neutral, and base, but a rough defi- 

 nition is easy enough. An acid is a substance that 

 reddens blue litmus-paper and that has a sour taste, 

 a neutral substance has no effect on litmus-paper, a 

 basic substance turns red litmus-paper blue, and 

 the more common bases, such as Caustic Potash, 

 Caustic Soda, etc., have an astringent caustic taste. 

 It is generally true that an acid body has a Hydrogen 

 that can easily be replaced by a metal. Thus 



