Question

When ethyl bromide is treated with moist $$\mathrm{Ag}_{2} \mathrm{O}$$, main product is:
A) ethyl methyl ether
B) ethanol
C) ethoxy ethane
D) all of the above

Answer 1

Hint: When ethyl bromide reacts with moist silver oxide, it forms two products. Out of which, one product is produced in a greater amount than the other. Thus it is the main product of the reaction.

Complete step by step solution:
Bromoethane, also known as ethyl bromide, is a chemical compound of the haloalkanes group. The preparation of EtBr stands as a model for the synthesis of bromoalkanes in general. It is usually prepared by the addition of HBr to ethene:
$$\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}+\mathrm{HBr} \rightarrow\mathrm{H}_{3}\mathrm{C}-\mathrm{CH}_{2} \mathrm{Br}$$
Bromoethane is inexpensive and would rarely be prepared in the laboratory. A laboratory synthesis includes reacting ethanol with a mixture of hydrobromic and sulfuric acids.
Silver oxide can be prepared by combining aqueous solutions of silver nitrate and alkali hydroxide. This reaction does not afford appreciable amounts of silver hydroxide due to the favourable energetics for the following reaction:
${{2} {AgOH}}$ →$$\mathrm{Ag}_{2} \mathrm{O}$$ + $$\mathrm{H}_{2} \mathrm{O}$$ (pK = 2.875)
With suitable control, this reaction could be used to prepare $$\mathrm{Ag}_{2} \mathrm{O}$$ powder with properties suitable for use as a fine-grained conductive paste filler.
$$\mathrm{Ag}_{2} \mathrm{O}$$ features linear, two-coordinate Ag centres linked by tetrahedral oxides. It is isostructural with $$\mathrm{Cu}_{2} \mathrm{O}$$. It "dissolves" in solvents that degrade it. It is slightly soluble in water due to the formation of the ion$$\mathrm{Ag}(\mathrm{OH})_{2}^{-}$$ and possibly related hydrolysis products. It is soluble in ammonia solution. A slurry of $$\mathrm{Ag}_{2} \mathrm{O}$$ is readily attacked by acids:
$$\mathrm{Ag}_{2} \mathrm{O}$$ + ${{2} {HX}}$ → ${{2} {AgX}}$ + $$\mathrm{H}_{2} \mathrm{O}$$
where $HX$ = $HF$, $HCl$, $HBr$, $HI$, or $$\mathrm{CF}_{3} \mathrm{COOH}$$. It will also react with solutions of alkali chlorides to precipitate silver chloride, leaving a solution of the corresponding alkali hydroxide.
Now, when ethyl bromide is mixed with moist $$\mathrm{Ag}_{2} \mathrm{O}$$, the main product is ethanol.
$$\mathrm{Ag}_{2} \mathrm{O}$$ + $$\mathrm{H}_{2} \mathrm{O}$$→2AgOH

$$\mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{2} \mathrm{Br}+\mathrm{AgOH} \rightarrow \mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{2} \mathrm{OH}+\mathrm{AgBr}$$
Moist $$\mathrm{Ag}_{2} \mathrm{O}$$ releases $OH-$ in low concentration as $AgOH$ is a weak base. When ethyl bromide is treated with moist $$\mathrm{Ag}_{2} \mathrm{O}$$ it gives ethyl alcohol as a major product.

Hence, the answer is (B).

Note: When ethyl bromide is heated in the presence of dry silver oxide then it gives diethyl ether and silver bromide as products, where diethyl ether is the major product.