Wed August 31, 2011 By: Piyush Das

Why aqueous solution of methyl amine reacts with Iron(III) Chloride to form ppt. iron(III) hydroxide?

Expert Reply
Thu September 01, 2011

Aqueous methylamine reacts with ferric chloride to precipitate hydrated ferric oxide:


Due to the +I effect of-CH3 group, methylamine is more basic than water. Therefore, in water, methylamine produces OH- ions by accepting H+ ions from water.

CH3-NH2   + H2O    CH3-NH3+    + OH-

Ferric chloride dissociates in water to form Fe3+  and  Cl- ions.

Then, OH- ion reacts with Fe3+ ion to form precipitate of hydrated ferric oxide.


Fe3+   +  6OH-   Fe2O3.3H2O

                           Hydrated ferric oxide

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