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Physics, Chemistry and Biology: Post your doubts here!

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about the oxidation of the ethanol
By potassium mangnate?
I dont think its required
but It depends whether the permanganate is a) in excess and b) has been sufficiently acidified.
C2H5OH ---MnO4------> CH3CHO + H20
CH3CHO ---MnO4------> CH3COOH
^I googled the answer............ :)
 
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I wanted to ask how to work this out? The mass of one mole of an alcohol is 116g. What is its formula?
i think you should use the the general formula CnH2n+1OH=116
which is 12n+(2n+1)+16+1=116
14n+18=116
14n/14=(116-18)/14
n=7
therefore alocohol is C7H15OH
 
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1,2g of magnesium reacts with a solution containing 2,74g of Hydrochloric acid .
what is the limiting reactant ?
HCL is in excess and Mg is the limiting reagent.
You first find the moles of both of them, and whichever has less number of moles is the limiting reagent, since the ratio between Mg and HCL is 1:1.
 
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2Mg+2HCl => 2MgCl+H2
Moles=Mass/Mr
Mg=1.2/24= 0.05
HCl=2.74/1+35.5=0.08
FROM EQUATION Mg:HCl= 2:2 = 1:1, which means both should be equal, but HCl is more than 0.05, thus it's in excess and Mg is the limiting reagent.
should it be MgCl or MgCl2 as Mg2+ combined with Cl- =MgCl2?
 
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should it be MgCl or MgCl2 as Mg2+ combined with Cl- =MgCl2?

Oops, my bad, it's mgcl2 :p
Mg+2HCl => MgCl2+H2

So the ratio Mg:HCl would be 1:2, so if Mg is 0.05 moles, then HCl should be 0.05*2 which is 0.1, but it's only 0.08, so HCl is the limiting reagent.
 
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