Answer
A dehydration reaction occurs when $CH_{3}CH_{2}OH$ is treated with $H_{2}SO_{4}$. On the other hand, when $CH_{3}CH_{2}OH$ is treated with NaH, a Williamson ether synthesis reaction occurs.
Work Step by Step
When an alcohol reacts with strong acids such as sulfuric acid and phosphoric aid at high temperatures, they undergo a dehydration reaction and produce an alkene and $H_{2}O$. Meanwhile, an ether is produced when a halide ion is displaced from an alkyl halide by an alkoxide ion that is prepared by the reaction of an alcohol and a strong base (e.g. NaH).
