Question

A suspension of $CaOC{{l}_{2}}$ in water is heated with ethanol. The product formed is:
[A] Ethylene
[B] Ethanol
[C] Trichloromethane
[D] Chloroethane

Answer 1

Hint: In the reagents that are given to us a series of reactions takes place before arriving at the final product. Firstly, the suspension mixture will form hydroxides and chlorine and the alcohol will react with the chlorine atoms and give us an aldehyde which will undergo further chlorination and the obtained product will react with the hydroxide to give us the final product along with a formate salt. The final product which is the correct answer is also known by the name chloroform.

Complete step by step answer:
When calcium hypochlorite is mixed with water to form a suspension and then heated with ethanol, it undergoes a series of different reactions forming different products and products react with each other to give us a final product. So let us discuss the reactions-
When calcium hypochlorite is mixed with water it gives calcium hydroxide along with chlorine. The reaction is-
     \[CaOC{{l}_{2}}+{{H}_{2}}O\to Ca{{\left( OH \right)}_{2}}+C{{l}_{2}}\]

Next, when we add ethanol to this, the chlorine reacts with the ethanol to give us aldehyde and hydrochloric acid. The reaction is-
     \[C{{H}_{3}}-C{{H}_{2}}-OH+C{{l}_{2}}\to C{{H}_{3}}CHO+HCl\]

Then, this aldehyde reacts again with chlorine and undergoes chlorination to give us chloral which is trichloroethane. The reaction is-
     \[C{{H}_{3}}CHO+3C{{l}_{2}}\to CHOCC{{l}_{3}}+3HCl\]

Then,2 moles of chloral reacts with the calcium hydroxide which was formed earlier and releases 2 moles of chloroform which is also known as trichloromethane and a formate salt with calcium. We can write the reaction as-
     \[2CHOCC{{l}_{3}}+Ca{{\left( OH \right)}_{2}}\to 2CHC{{l}_{3}}+{{\left( HCOO \right)}_{2}}Ca\]

As we can see from the above reactions, the final product was trichloromethane and formate salt with calcium.
So, the correct answer is “Option C”.

Note: A suspension mixture is a heterogeneous mixture. A suspension mixture contains solid particles large enough so that they can undergo sedimentation.
As we have discussed above, calcium hypochlorite with water gives us calcium hydroxide and chlorine hence acts as a bleaching agent. The chlorine acts as an oxidising agent and hence reacts with the dye and bleaches it.