Question

Do you expect the carbon hydrides of the type (C_nH_2n + 2) to act as ‘Lewis’ acid or base? Justify your answer.

Answer 1

For carbon hydrides of type C_nH_{2n + 2}, the following hydrides are possible for 

For a hydride to act as a Lewis acid i.e., electron accepting, it should be electrondeficient. Also, for it to act as a Lewis base i.e., electron donating, it should be electronrich. 

Taking C₂H₆ as an example, the total number of electrons are 14 and the total covalent bonds are seven. Hence, the bonds are regular 2^e– -2 centered bonds. 

Hence, hydride C₂H₆ has sufficient electrons to be represented by a conventional Lewis structure. Therefore, it is an electron-precise hydride, having all atoms with complete 

octets. Thus, it can neither donate nor accept electrons to act as a Lewis acid or Lewis base.