at this site below,
http://projects.icbse.com/chemistry-306
I cannot understand the line 'Then add 2-3 drops of ferric chloride solution and acidify with dilute HCl.'
b/c in many cases, the detection of phenol requires to put NaOH to neutralize HCl which is formed by ferric chloride (iron(III) chloride).
what I'd like to know is 'why do I need to acidify rather than to neutralize w/ sodium hydroxide' and 'what material does HCl neutralize'.
I am not a native English speaker, so please understand. Thanks.
http://projects.icbse.com/chemistry-306
I cannot understand the line 'Then add 2-3 drops of ferric chloride solution and acidify with dilute HCl.'
b/c in many cases, the detection of phenol requires to put NaOH to neutralize HCl which is formed by ferric chloride (iron(III) chloride).
what I'd like to know is 'why do I need to acidify rather than to neutralize w/ sodium hydroxide' and 'what material does HCl neutralize'.
I am not a native English speaker, so please understand. Thanks.
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A solution of ferric chloride undergoes hydrolysis forming some Fe(OH)3. The addition of HCl prevents this hydrolysis and allows the Fe+++ to react.