Question

How is ethanoic acid prepared from dry ice?

Answer 1

Ethanoic acid is also known as acetic acid and dry ice is the solid form of carbon dioxide gas. Acetic acid has –COOH functional group which is responsible for its properties.

Complete step by step answer:
-When dry ice reacts with Grignard reagent in presence of dry ether then acetic acid is formed. Grignard reagent is $R - Mg - X$ where R is alkyl group and X is halide. Here the Grignard reagent used is Methyl Magnesium Iodide.
-When Grignard reagent reacts with dry ice an intermediate compound called adduct is formed.
The adduct is treated with water in presence of dilute acid.
The reaction is as follows-
$\Rightarrow C{O_{2\left( s \right)}} + C{H_3}MgI\xrightarrow{{{\text{dry ether}}}}\mathop {\left[ {C{H_3} - COOM{g^ + }{I^ - }} \right]}\limits_{Adduct} \to C{H_3}COOH + Mg\left( I \right)OH$
-Acetic acid can also be prepared using Methyl Magnesium Bromide instead of Methyl Magnesium Iodide. Both give the same reaction.Some properties of acetic acid are-
Acetic acid is a clear, colourless liquid which is soluble in water.
-It smells like vinegar.
-Since it turns blue litmus red, it is a weak acid.
-When acetic acid is undiluted means no water is added in it then it is known as glacial acetic acid which freezes at ${16.6^ \circ }{\text{C}}$.
-When it is in concentrated form it is corrosive and can cause damage to the skin.

Note:
The uses of acetic acid are-
1.It is used as antiseptic against pseudomonas, streptococci, staphylococci and other bacteria.
2.It is used in cervical cancer screening .
3.It is used to treat many infections and it is used as an agent to lyse red blood cells.
4.It is used in manufacture of acetic anhydride, ester, vinyl acetate monomer and vinegar.
5.It is used as a solvent for recrystallization as it purifies organic compounds.
6.It is used to make ink and dyes and in perfumes.