Am.  Jour.  Pharm. 
Jan.,  1886. 
Sodium  Chlorate. 
15 
SODIUM  CHLORATE. 
By  F.  Holbeeg. 
(Read  at  the  Pharmaceutical  Meeting,  December  15th,  1885.) 
Owing  to  a  difference  of  authorities  as  to  whether  chlorate  of  sodium 
when  heated  to  melting  gives  off  oxygen  and  leaves  a  residue  having 
a  neutral  reaction,  or  whether  chlorine  and  oxygen  are  given  off  and 
the  residue  has  an  alkaline  reaction,  the  following  investigations  were 
made  in  the  Chemical  Laboratory  of  the  Philadelphia  College  of 
Pharmacy  to  determine  the  cause  of  this  difference. 
Experiment  1. — A  small  quantity  of  sodium  chlorate  of  German 
manufacture  was  heated  and  gave  off  oxygen,  the  residue  when  dis- 
solved in  water  had  a  neutral  relation. 
Experiment  2. — Some  of  the  salt  was  prepared  by  decomposing 
sodium  fluosilicate  with  potassium  chlorate.  The  resulting  salt  on 
heating  gave  no  evidence  of  anything  but  oxygen  being  given  off  and 
the  residue  had  a  neutral  reaction. 
Experiment  3. — Another  quantity  of  the  salt  was  made  by  acting 
on  acid  sodium  tartrate  with  potassium  chlorate.  The  resulting  sodium 
chlorate  on  heating  gave  off  fumes  which  bleached  blue  litmus  paper, 
and  the  residue  had  an  alkaline  reaction. 
Experiment  4. — A  minute  quantity  of  acid  potassium  tartrate  was 
mixed  with  the  pure  sodium  chlorate.  The  mixture  on  heating  gave 
off  fumes  which  bleached  blue  litmus  paper  (thus  showing  the  presence 
chlorine),  and  the  residue  had  an  alkaline  reaction. 
Experiment  5. — A  minute  quantity  of  acid  potassium  tartrate  was 
mixed  with  potassium  chlorate.  This  mixture  on  heating  also  gave 
off  fumes  which  bleached  blue  litmus  paper  and  the  residue  had  an 
alkaline  reaction. 
From  the  experiments  made  it  appears,  that  the  chlorates  when  con- 
taminated with  a  trace  of  organic  matter  will  give  off  chlorine  and 
leave  a  residue  having  an  alkaline  reaction. 
One  of  the  processes  recommended  for  the  preparation  of  sodium 
chlorate,  is  by  decomposing  acid  sodium  tartrate  with  potassium  chlo- 
rate. The  salt  prepared  in  this  way  has  probably  caused  the  state- 
ment, that  on  heating  chlorine  is  given  off  and  the  residue  gives  an 
alkaline  reaction,  which  is  due  to  a  trace  of  organic  matter.  For  this 
reason  sodium  chlorate  should  be  prepared  by  a  process  which  will 
exclude  all  possibility  of  contamination  with  organic  matter. 
