Question

Ether is obtained from ethyl alcohol in presence of ${{H}_{2}}S{{O}_{4}}$ at?
A) 113 K
B) 443 K
C) 413 K
D) 213 K

Answer 1

Hint: The answer here is based on the organic chemistry concept that deals with the reaction of alcohols and acid that produces a dehydrated product that is elimination of alcohol group in the form of water take place and this happens at a temperature where symmetrical ether is produced.

Complete step by step answer:
In the lower class of chemistry, we have studied about the concepts of the organic reactions and the various types in it.
- We shall now see what happens when ethyl alcohol is treated with sulphuric acid and at what temperature, ether is produced.
- Ethyl alcohol having the molecular formula $C{{H}_{3}}-C{{H}_{2}}-OH$ reacts with sulphuric acid in two possible cases.
- Case one includes the treatment of ethyl alcohol which is present in excess with that of the sulphuric acid at normal amount and then the product formed in this type is an alkene that is nothing but ethane which is having the molecular formula $C{{H}_{2}}=C{{H}_{2}}$ .
- This type of product is obtained only when the temperature is high at which about 443 K is employed and this temperature favours the formation of alkene if excess ethyl alcohol is used.
- Now, in case two, we will make use of excess amounts of ethyl alcohol itself but slightly change in the temperature because the change in the temperature yields different products when alcohol is treated with sulphuric acid.
- Here, at this condition ether will be obtained that is nothing but diethyl ether ${{C}_{2}}{{H}_{5}}O{{C}_{2}}{{H}_{5}}$ where the temperature employed for this condition is lesser than that used in the case one.
Thus, the temperature of about 413 K gives the ether which is symmetrical and therefore the correct answer for this question .So the correct answer is “C”:

Note: Usually acid catalysed productions of ethers which are the symmetrical ethers that are obtained by the primary alcohols are temperature dependent. At around 383 K to about 403 K an ether is obtained by the ${{S}_{N}}2$ reaction and at higher temperatures that is above 423 K, an alkene is obtained because of E2 elimination reaction.