what is X and R ?
* X represents the Halogens(F,Cl,Br,I)
eg: HX - can be HCl,HF,HBr,HI
* R represents alkyl group having general formula CnH2n+1 (R is only used in organic chemistry)
eg:(1) R-OH represents alcohol [methanol-if R is methyl,ethanol-if R is ethyl,propanol-if
R is propyl.....]
(2) R-X represents alkyl halides (Chloro propane-if R is propyl,Bromo butane-if Ris butyl)
Hope it is clear 4 u