HYDROCARBONS 9 



tetrahedron with one hydrogen (in the case of methane) situated 

 at each apex. 



Methane 



Such a formula was suggested by van't Hoff and is, because of 

 the wonderful way in which it explains and agrees with facts, 

 universally accepted as the complete structural or stereo- 

 chemical (space relation) formula for methane. For the sake 

 of expression on a plane surface in writing, this formula is 

 modified to show only two dimensions, but retaining the ideas 

 of symmetry, tetra valence and saturation : 



H 



H— C— H 



I 

 H 



Methane 



This formula is the plane structural formula to represent 

 methane and to indicate the three facts previously mentioned : 

 (i) saturation of carbon, (2) symmetry of the compound, i.e. 

 all the hydrogen atoms are alike in relation to the carbon, and 

 (3) tetravalence of carbon. 



EXPERIMENT STUDY II 



Methane, Marsh Gas 



(i) (a) Mix in a mortar 10 grams fused, dry sodium acetate and 

 20 grams fine soda lime. Fill a test tube (hard glass) about half full, 

 and hold horizontally and tap until the contents lie in the tube leav- 

 ing a space along the top. Incline the tube slightly downward when 

 heating. Connect the tube by means of glass and rubber tubing so 

 as to generate gas and collect over water in small bottles or test 



