128 
Action  of  Hydrogen  Peroxide. 
/  Am.  Jour.  Pbarm. 
I      March,  1892. 
Titanic,  molybdic,  tungstic  and  vanadic  acids  in  presence  of  H2S04 
give  yellow  or  orange  colored  solutions.  Thallous  oxide  becomes 
brown,  due  to  formation  of  thallic  oxide.  Indigo  solution  is  decol- 
orized after  addition  of  FeS04.  Guaiac  solutions  become  blue  after 
the  addition  of  FeS04  (distinction  from  ozone  and  chlorine). 
Hydrogen  peroxide  has  been  proposed  as  a  test  for  molybdenum, 
molybdates  in  acid  solution  becoming  deep  yellow  (claimed  to  be 
due  to  the  formation  of  a  higher  oxide).  In  quantitative  analysis  it 
is  used  in  the  oxidation  of  ferrous  salts  ;  in  the  separation  of  man- 
ganese from  zinc,  cobalt  and  nickel ;  of  zinc  from  cobalt  and  nickel 
and  in  the  determination  of  potassium  permanganate,  of  bleaching 
powder,  of  potassium  ferricyanide,  of  potassium  chromate,  of  man- 
ganese dioxide,  of  lead  dioxide. 
Hydrogen  peroxide,  in  alkaline  solutions,  speedily  decomposes, 
and  is  more  permanent  in  acid  than  in  neutral  solutions ;  all  min- 
eral salts  excepting  the  alkaline  chlorides,  nitrates  and  sulphates, 
and  mercuric  chloride  have  a  decomposing  effect ;  the  addition 
of  alcohol,  ether,  phenol,  thymol,  menthol  to  nearly  neutral 
solutions  have  a  preservative  effect.  In  a  paper  published  by  Dr. 
G.  Kassner  (abstracted  in  the  Am.  Journ.  Pharm.,  1889,  565)  "  the 
preparation  of  oxygen  is  described  from  potassium  ferricyanide  and 
hydrogen  peroxide  in  the  presence  of  potassium  hydrate.  The  state- 
ment is  there  made  that  the  reaction  progresses  only  in  alkaline 
solution,,  and  that  as  soon  as  the  potassium  hydrate  is  used  up  in 
the  formation  of  potassium  ferrocyanide,  according  to  the  reaction : 
H202  +  K6Fe2(CN)12  +  2KOH  =  2K4F(CN)6  +  2H20  +  02 
the  evolution  of  oxygen  ceases,  but  that  the  liberation  of  oxygen  will 
continue  upon  further  addition  of  KOH  as  long  as  both  H202  and 
K6Fe2(CN)12  remain." 
A  brief  abstract  of  a  very  recent  article  by  W.  Kwasnik,  "The 
action  of  barium  peroxide  upon  metallic  salts,"  Arch,  der  Pharm., 
1 89 1,  573,  may  prove  interesting  for  comparison  :  "  This  study  was 
incited  by  the  process  of  Dr.  G.  Kassner  for  making  oxygen  from 
barium  peroxide  and  potassium  ferricyanide :  taken  in  molecular 
proportion  and  covered  with  water,  these  materials  will  give  up 
oxygen  in  the  cold,  the  ferricyanide  being  reduced  to  ferrocyanide 
according  to  the  reaction  : 
Ba02  +  K6Fe2  (CN)12  =  K6Ba(Fe(CN)6)2. 
