Am.  Jour.  Phftrm.  ) 
January,  1»10.  / 
A  n  i  n  i  o  n  ium  B'enzoate. 
[3 
the  excess  of  acid  remaining  in  the  receiving  flask  titrated,  after 
cooling,  with  standard  ammonia  solution,  using  cochineal  as  the 
indicator.  The  free  alkali  remaining  in  the  distilling  flask  may 
also  be  determined  by  titration,  with  0.1  N  H2S04  using  phenol- 
phthalein,  but-  calculations  made  from  this  titration  are  subject  to 
the  error  arising  from  the  alkali  dissolved  from  the  glass  of  the 
distilling  flask  and  also  from  inaccuracies  of  the  indicator.  With 
TABLE  I. 
ANALYTICAL  RESULTS   OBTAINED   UPON   AMMONIUM    BENZOATE    SAMPLES  BY 
THE  DISTILLATION  METHOD. 
(50  c.c.  0.1  N  NaOH  and  50  c.c.  0.1  N  H2S04  used  respectively  in  the  dis- 
tilling and  receiving  flasks  for  each  determination.) 
Sample 
Distilling  flask 
Receiving  flask 
X 
£ 
0 
0 
CJ 
w 
c 
!■§ 
Description 
Wt. 
used 
CO 
03  nJ 
X* 
"  Ui 
Z  oi 
~  0 
1  X 
O  <u 
.  u 
0  0 
cP 
X 
O  0 
A  co 
M  £0 
°'SX 
*~0 
EO 
3° 
go 
Xx 
A*  w 
K» 
~Z 
O  « 
.  1- 
o  0 
0 
d  . 
a 
.0 
go 
3° 
No.  220  
No.  222  
No.  223  
No.  220  recryst.  (a)  .  . 
No.  220  recryst.  (b).  . 
No.  220  recryst.  (c) .  . 
No.  220  recryst.  (c^  . 
No.  220  recryst.  (c2)  . 
No.  220  recryst.  (c3)  . 
No.  220  recryst.  (c4)  . 
o.5 
0-5 
0-5 
o-5 
o-5 
0.5 
0.564 
o-4323 
0.4365 
0.4838 
0.4186 
0.2466 
14.O 
139 
13-85 
13-75 
13-9 
14.0 
9-4 
18.65 
13-3 
14.6 
1935 
36.0 
36.1 
36.15 
36.25 
36.1 
36.0 
40.6 
3J-35 
3i-7 
35-4 
3°-°5 
18.9 
.006 
.005 
.003 
.004 
•003 
•003 
.003 
.0067 
.0232 
•0330 
•0494 
.  1062 
14.5 
14-35 
14. 1 
14. 1 
14.15 
M-3 
9.6 
19.2 
20.2 
17-3 
234 
39-8 
35-5 
35-65 
35-9 
35-9 
35-85 
35-7 
40.4 
30.8 
29.8 
32-7 
26.6 
10.2 
.494 
.496 
•499 
•499 
.498 
.496 
.498 
.428 
•415 
•455 
•370 
.142 
98.8 
99.2 
99.9 
99-9 
99-7 
99.2 
99.6 
99.1 
95-° 
94.0 
88.4 
57-5 
In  the  above  table  the  designations  "  recrystallized  (c),  (Cj),  (c2),"  etc., 
refer  to  the  same  sample  of  purified  ammonium  benzoate,  which  was  dried 
in  a  Hempel  desiccator  containing  H2S04  and  at  about  50  mm.  Hg  pressure 
for  successive  periods  of  time.  These  periods  were  respectively  about  1,2, 
5,  and  8  days. 
samples  containing  large  amounts  of  free  benzoic  acid,  however,  this 
latter  titration  serves  as  a  useful  check  upon  the  results  calculated 
from  the  ammonia  determination.  The  character  of  the  results 
which  may  be  obtained  by  the  method  as  above  outlined  are  given 
in  Table  I. 
In  connection  with  the  distillation  method,  it  should  be  men- 
tioned  that  on  account  of  the  low  percentage  of  ammonia  (NH3  = 
