ROH + CH3CH2MgBr = CH3CH3

any compound containing active hydrogen on treating with ethyl magnesium bromide gives ethane

Treat C₂H₅MgX with H2O or alcohol or any other H+ ion donor, in this way ethane would be formed

grignard reagent are very reactive, they abstract H atom from any source of proton and forms alkanes.

to prepare ethane u can take CH₃CH₂MgCl +  H₂O or dil HCl ------> CH₃CH₃