$2 R - X +2 Na \stackrel{\text { Dry ether }}{\longrightarrow} R - alkane +2 NaX$
Where $R$ is an alkane $X$ is a halide.
All other process are used for preparation for amines.
$(I)$ Benzylchloride
$(II)$ $p-$ Methoxy benzyl chloride
$(III)$ $p-$ Nitro benzyl chloride