Caustic soda is used to separate a mixture of ferric chloride and aluminium chloride. Explain.

Caustic soda is used to separate a mixture of ferric chloride and alum

1.	Caustic soda is used to separate a mixture of ferric chloride and aluminium chloride. Explain.
Answer» Solution :Both FERRIC chloride and aluminium chloride react with caustic SODA to GIVE the respective metal hydroxides. `FeCl_(3)+3NaOHrarr Fe(OH)_(3)+2NaCl` `AlCl_(3)+3NaOH RARR Al(OH)_(3)+3NaCl` `Fe(OH)_(3)` is basic, but `Al(OH)_(3)` is amphoteric. `Al(OH)_(3)` is soluble in excess caustic soda to give sodium meta aluminate. `Al(OH)_(3)+NaOHrarrNa[Al(OH)_(4)]` `Fe(OH)_(3)`is insoluble and is separated by filtration.