392      Hypophosphorous  Acid  and  Hypophosphites.  {^JJXmsK111, 
In  No.  1  we  have  the  first  and  only  salt  in  which  phosphite  was 
present,  and  this  did  not  yield  a  precipitate  with  acetic  acid  and  lead 
acetate.  0*517  gram,  after  oxidation  with  Br,  required  22*9  cc.  NaOH 
for  neutralization,  to  this  must  be  added  the  value  of  9*73  percent.  K2 
C03,  or,  as  NaOH,  0*73  cc,  a  total  of  23*63  cc. ;  from  this  is  subtracted 
the  correction  0*3  cc,  and  the  number  of  cc.  of  NaOH  corresponding 
to  the  hypophosphite  is  23*3,  which,  multiplied  by  0*01735  and 
divided  by  0'517,  will  give  as  the  amount  of  KH2P02  0*4047  gram, 
or  78*27  per  cent.  From  the  amount  of  magnesium  pyrophosphate 
82*66  per  cent.  KH2P02  is  calculated. 
82*66  —  78*27  =  4*39  per  cent,  is  the  equivalent  of  K2HP03, 
expressed  as  KH2P02,  and  from  which  by  proportion  is  obtained 
the  amount  of  phosphite. 
KH2P02  :  2K2HP03  as  the  difference  :  x  the  amount  of  phosphite, 
104*1         316*4  4*39  13*34  per  cent. 
The  amount  of  KH2P02  is,  78*27  the  combined  reducing  value 
minus  4*39  the  reducing  value  of  13*34  per  cent.  K2HP03  or,  73*88 
per  cent. 
SODIUM  HYPOPHOSPHITE. 
Prepared  like  the  potassium  salt  and  according  to  the  U.  S.  P.  should 
have  one  molecule  water  of  crystallization.  Three  samples  were  ex- 
amined, with  results  which  lead  to  the  suggestion  that  greater  uniformity 
in  the  commercial  article  might  be  obtained  by  replacing  the  present 
officinal  by  the  anhydrous  salt. 
TJ.  S.  P.  Formula. 
I. 
II. 
III.1 
NaH2P02, 
83-02 
85-00 
89.98 
98-06 
H20, 
16-98 
13-70 
8-44 
1-06 
NaCl, 
0*52 
021 
0-43 
Na2S04, 
0'71 
1-19 
031 
FERRIC  HYPOPHOSPHITE. 
For  this  salt  two  entirely  distinct  processes  of  manufacture  have 
been  published.  1.  By  double  decomposition  of  ferrous  sulphate  and 
calcium  hypophosphite ;  the  calcium  sulphate  formed  being  but  spar- 
ingly soluble  is  removed  by  filtration  and  the  filtrate,  containing  fer- 
rous hypophosphite,  during  evaporation  is  stated  to  yield  ferric  hypo- 
phosphite  by  oxidation  of  the  ferrous  salt.  Apart  from  the  wrong 
impression  which  is  received  from  the  above  statement  that  the  hypo- 
1  Ca,  a  trace. 
