COLORIMETRIC ESTIMATION OF NICKEL AND COBALT. 



411 



Given Found 



Error 



Ni = '04664 '04668 



+ -00004 



Oo = -01171 -01167 



- -00004 



FIRST SERIES. 





Mixed 

 metals 



Grams 



Colour 



NiorC 



o added 



Total 



metals in 



50 cc. 



Grams 



Given 



Found 



•04668 



Error 



cc. 



Grams 



•05835 



greenish 



•45 Co 



•00263 



•06098 



Ni -04664 



+ -00004 













Co -01171 



-01166 



- -00004 



•05203 



bright 









Ni -01982 



•02043 



+ -0006 



^ taken 



pink 



3-55 M 



04139 



•06741 



Oo -03221 



•0316 



- -0006 



•05016 



pale 



1-4 Co 



•0082 



•05836 



Ni -04431 



■04467 



+ -00036 





green 









Oo -00585 



•00549 



- -00036 



•02922 



pink 



2-85 Ni 



•03323 



•06245 



Ni -01457 

 Oo -01464 



•01457 

 •01464 



•oooo 



•0000 



•05073 



green 



l-95Co 



•01142 



•06115 



Ni -04781 



•04758 



- -00023 



+ 5cc. 16 



E.HN0 2 









Co -00293 



•00315 



+ -00023 



Percent- 

 age error 

 on weight 

 of mixed 



metals 



07 



72 



00 



95 



Maximum error (No. 2) -0006 gin. in -052 grams = 1-1% 



In the subsequent experiments the solutions used were 

 made of a slightly different strength so that in colour effect 

 one cc. of each were approximately equivalent to one 

 another. 



Nickel Solution. 



Kahlbaum's Oo free NiS0 4 , electrolysed under the usual 

 conditions and the precipitated Ni dissolved in HN0 3 , 

 evaporated almost to dryness on water bath and diluted to 

 the required bulk. It contained 



2*7449 grams Ni in 274*49 cc. distilled water 

 •01 „ Ni in 1*0 cc. 



Cobalt Solution. 



Kahlbaum's Ni free OoS0 4 , electrolysed and the precipi- 

 tated Co dissolved in HNO ;i , evaporated almost to dryness 

 on water bath and diluted to required bulk. It contained 

 2*0156 grams Oo in 671*86 cc. 

 *003 „ Oo in 1* cc. 



