Extraction of f-block element, Chemistry

Assignment Help:

Q. Extraction of f-block element ?

As all the lanthanides occur together in nature, their extraction involves two main steps: (i)   separation from one another and (ii) reduction of their compounds to metals. Since the lanthanides are all typically trivalent and are almost identical in size, their chemical properties ark almost similar. Thus, the separation of lanthanides from one another is a very difficult task, almost as difficult as the separation of isotopes. Only europium and cerium will be separated from the remaining lanthanides by employing conventional  Q+  chemical methods because of stabilities of Ce 4+and EU2+ in aqueous solution. Cerium can be separated from a mixture of lanthanides by oxidising ce3+ to ce4+ with permanganate or bromate or hypochlorite in an alkaline medium and subsequently precipitating it as Ce02.  Europium can be reduced to EU2+ either by electrolytic reduction with a mercury cathode or by using zinc amalgam. It is then precipitated from the solution as EuSo4.

Earlier the lanthanides used to be separated from each other by selective precipitation or by fractional crystallisation. With a limited amount of a precipitating agent, the substance uhichis least soluble is precipitated first. For example, if a base is added to a solution of  lanthanide nitrates, the least soluble Lu(OH)3 is precipitated first and the most soluble -  La(OH)3 last. As only a partial separation is effected, the precipitate is redissolved and the method is repeated several times.


Related Discussions:- Extraction of f-block element

Cyrogenic technology, what is cyrogenic technology ?? explain with definati...

what is cyrogenic technology ?? explain with defination please

Propose a mechanism for substitution of an aryl bromide, Nucleophilic aroma...

Nucleophilic aromatic substitution is possible, but involves substitution of a typical leaving group rather than a hydrogen atom. Remembering that S N 2 and S N 1 mechanisms are no

Calculate the value for the standard molar reaction entropy, Calculate the ...

Calculate the Value for the Standard Molar Reaction Entropy? Derive an expression for the standard molar reaction entropy of a reaction that can be used to calculate its

Arylaldehyde, preparation of arylaldehyde from etards reaction

preparation of arylaldehyde from etards reaction

The quantum number n2 which produces this transition, The frequency of one ...

The frequency of one of the lines in Paschen series of hydrogen atom is2.340x10 11 Hz. The quantum number n 2 which produces this transition is: (1) 6               (2) 5

Polymers, polymers based upon availabilty

polymers based upon availabilty

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd