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Does the hydrogen need to be attach to carbon to make it organic, or it will be organic even if the hydrogen is not attached to carbon atoms?

Hi there!

Yes, in order to be classified organic, a molecule must include both carbon and hydrogen, with the hydrogen bonded to carbon atoms. This is because the traditional concept of organic substances is based on carbon-hydrogen and carbon-carbon bonds. 

Hey there! This means that the carbon bearing the leaving group should be unsubstituted. CH3X and 1° alkyl halide will preferably react via the SN2 mechanism compared to 2° or 3° alkyl halides. I hope this clears things up!