[frankenstein18]

So E2 dehydration reaction of primary alcohols form an elimination product and a SN2 product which was an ether. 
My book gives me the mechanism reaction for the E2 elimination that's happening.

But before that I had read on the same book a few sections before that the SN2 reaction for a primary alcohol formed a substitution product, which was an alkyl halide!

So now I am very confused as to what happens with a primary alcohol in an SN2 reaction

Can someone explain? In both reactions dehydration occurs so I really don't know

Does a SN2 dehydration reaction form an ether as well as an alkyl halide?

[clarkstill]

The name Sn2 doesn't relate to the formation of any particular product. All it means is that the reaction is a nucleophilic addition where both the nucleophile and electrophile are involved in the rate-determining step (so the reaction is 2nd order). This is to be compared with Sn1 reactions, where the nucleophile is not involved in the rate determining step.

So Sn2 reactions can form ethers, alkyl halides, alkyl azides, amines, alkanes... etc.

[Babcock_Hall]

Does a SN2 dehydration reaction form an ether as well as an alkyl halide?

A dehydration is a type of elimination reaction, which proceeds by the E2 mechanism in this case.  Ethers and alkyl halides are the products of substitution reactions.