[sweetchinmusic]

1.Why sodium dichromate is used in place of potassium dichromate in (experiment)preparation of butanone

2.What is the purpose of preparing butanone 2,4-dinitrophenylhydrazone in preparation of butanone ?

3.And there is some data:
mass of butan-2-ol : 4.03g
mass of butanone : 4.00g
7.15g sodium dichromate-2-water

would anybuddy mind kindly telling me how to calculate the yield of butanone obtained ?


=============THX A LOT==============

[sweetchinmusic]

I know the ans of 1st question

can you help me for Q2&Q3?

[tmartin]

For question 2, my guess is if this is for a lab course, there should be an answer in the pre-lab or some other reading with the lab (most labs I've TA'ed had answers "hidden" somewhere in the reading).

For question 3, you'll need to know the molecular weights of the starting material and product in order to determine how many moles of each you have.  Once you know the moles of product you expected to obtain, as you already have moles of butanone (or can determine), you can determine your percent yield.