Qualification > Sciences
Edexcel CHEMISTRY DOUBTS!!!!
EVIL DOCTOR:
--- Quote from: Summer :] on May 09, 2010, 04:46:22 pm ---i have a question
why do we have to add the sulphuric acid slowly when preparing the bromoalkane from alcohol?
--- End quote ---
So it will not explode as reaction is exothermic
Saladin:
--- Quote from: ksitna on May 09, 2010, 06:25:51 pm ---i dont get how to calculate the percentage yield and error
does anyone have any notes on these?
--- End quote ---
How about you give a question, and I help you with it. You can post in the Edexcel CHEMISTRY doubts area.
wrongaccount:
there is this point the syllabus that i dont understand please could someone answer this before the exam ??
"Carry out the preparation of an halogenoalkane from an alcohol and
explain why a metal halide and concentrated sulfuric acid should not
be used when making a bromoalkane or an iodoalkane."
why cant Concen. H2SO4 be used neither a metal halide ?
Summer :]:
--- Quote from: helai on May 10, 2010, 12:21:44 am ---there is this point the syllabus that i dont understand please could someone answer this before the exam ??
"Carry out the preparation of an halogenoalkane from an alcohol and
explain why a metal halide and concentrated sulfuric acid should not
be used when making a bromoalkane or an iodoalkane."
why cant Concen. H2SO4 be used neither a metal halide ?
--- End quote ---
this point is wrong though :s we use concentrated sulphuric acid to make bromoalkanes!! and a metal halide
but the point might be referring of why it should not be used
because it releases many by products
such brome or iodine depending on which halogenoalkane you are making...and it releases sulphur dioxide
Uchia:
Summer don't confuse the guy i'll tell you the right answer
sulphuric acid is a stong enough oxidising agent so a concentrated sulphuric acid couldn't be used because it will further get reduced it self and will oxidise the halide ion to form iodine or bromine resulting in now HI or HBr for the reaction with alcohol to form haloalakane.
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