Explain why the dehydration of primary alcohols can only be used for preparing symmetrical ethers. what would happen if a mixture of two different alcohols were used as the starting material in this reaction?

Only primary alcohols give symmetrical ethers and a mixture of products is obtained when different starting materials are used.

Explanation:

Preparation of symmetrical ethers proceed smoothly with primary alcohols between 110°c to 130°c. Use of secondary or tertiary alcohol leads to the formation of an alkene. Also a mixture of products is obtained with different starting materials which isn't the intended purpose.