Amseptf,"i889arm'}    Hypophosphorous  Acid  and  Hypophosphites.  461 
It  will  be  seen  that  only  in  No.  1  the  acidity  exceeds  the  reducing 
value,  but  this  is  found  by  the  complete  analysis  to  be  due  to  an 
excess  of  sulphuric  acid  having  been  used  in  its  preparation  ;  the  0*38 
CaO  is  the  only  basic  constituent  found,  to  neutralize  which  0*66  HgSO^ 
is  required,  leaving  an  excess  of  2*03  per  cent,  sulphuric  acid,  which  in 
the  original  neutralization  was  expressed  as  2-66  per  cent.  H3P02, 
this  being  the  excess  of  acidity  over  the  reduction.  As  H2S04  is 
dibasic  and  H3P02  monobasic,  one  molecule  of  the  former  is  equivalent 
to  two  molecules  of  the  latter,  and  by  the  equation  these  2*03  per 
cent.  H2S04  are  equivalent  to  2*72  per  cent.  H3P02 
H2S04  :  2H3P02 
98     :      132    : :  2*03  :  x  —  272  per  cent. 
These  calculations  prove  the  absence  of  phosphorous  acid,  although 
its  presence  was  indicated  by  the  relationship  of  the  neutralization 
and  reducing  values ;  moreover,  the  sample  gave  a  decided  precipitate 
with  the  acetic  acid  and  lead  acetate  test. 
The  other  samples  show  a  greater  reducing  than  neutralizing  value, 
indicating  at  once  the  presence  of  undecomposed  calcium  hypophos- 
phite.  The  calculations  in  these  cases  were  made  as  follows:  After 
the  removal  and  estimation  of  the  calcium  phosphate  and  oxalate,  if 
present,  the  calcium  oxide  remaining  in  the  solution  was  found, 
and  from  this  substracted  sufficient  CaO  to  neutralize  the  H2S04, 
present  in  the  acid;  the  remaining  GaO  was  then  calculated  as 
Ca(H2POj,)2  and  the  figures  obtained  in  this  way  agreed  very 
well  with  those  calculated  from  excessive  reduction  over  neutraliza- 
tion. 
The  specific  gravities  given  were  taken  at  15*5°C.  The  cal- 
culations give  the  following  percentage  composition  to  the  pur- 
chased samples: 
I.  II.  III.  IV. 
Sp.  Gr.         1-34778         T15761  1-18011  1-21373 
H3P02  30-11  32-76  3822  4476 
Ca(H2P02)2    1-84  1-35  0  85 
H2S04  203       
CaS04  0-92  trace  0*37  0"96 
CaC204      0-36  0-71 
Ca3(P04)2    0-11     
From  the  results  it  is  evident  that  the  reason  of  the  commercial 
acid  running  so  low  is  that  there  is  never  sufficient  material  taken  to 
