﻿Broionhig 
  — 
  Volumetric 
  Estimation 
  of 
  Cerium. 
  

  

  455 
  

  

  CeOj, 
  were 
  drawn 
  off 
  into 
  bottles 
  previously 
  filled 
  with 
  carbon 
  

   dioxide, 
  treated 
  with 
  the 
  usual 
  amount 
  of 
  strong 
  hydrochloric 
  

   acid 
  (IC^™^), 
  and 
  after 
  standing 
  from 
  thirty 
  to 
  forty-five 
  min- 
  

   utes, 
  neutralized 
  and 
  titrated 
  as 
  already 
  described. 
  The 
  results 
  

   were 
  most 
  interesting 
  and 
  seemed 
  to 
  show 
  a 
  loss 
  of 
  iodine 
  

   closely 
  equivalent 
  to 
  that 
  shown 
  by 
  the 
  results 
  of 
  Table 
  III, 
  

   and 
  proportional 
  to 
  the 
  amount 
  of 
  iodine 
  originally 
  present. 
  

   A 
  few 
  determinations 
  were 
  carried 
  through 
  in 
  the 
  same 
  way 
  

   except 
  that 
  the 
  neutralization 
  was 
  omitted 
  and 
  dilution 
  and 
  

   titration 
  with 
  thiosulphate 
  substituted. 
  These 
  showed 
  a 
  loss 
  

   of 
  iodine 
  well 
  within 
  the 
  limits 
  of 
  such 
  a 
  process. 
  The 
  results 
  

   follow 
  in 
  Table 
  lY. 
  

  

  

  

  Table 
  

  

  lY. 
  

  

  

  

  

  With 
  Arsenious 
  Oxide, 
  

  

  

  

  Iodine 
  -^-^ 
  

  

  N 
  Iodine 
  ^\ 
  

  

  

  Equivalent 
  

  

  

  taken. 
  

  

  found. 
  

  

  Error. 
  

  

  error 
  on 
  CeOj. 
  

  

  

  cm^. 
  

  

  cnr^ 
  ' 
  

  

  cm^. 
  

  

  grm. 
  

  

  (1) 
  

  

  5-22 
  

  

  5-07 
  

  

  0-15 
  — 
  

  

  0-0026— 
  ^ 
  

  

  (2) 
  

  

  5-09 
  

  

  4-97 
  

  

  0-12 
  — 
  

  

  0-0021- 
  

  

  (3) 
  

  

  5-10 
  

  

  4-97 
  

  

  0-13 
  — 
  

  

  0-0022- 
  

  

  (4) 
  

  

  5-66 
  

  

  5-47 
  

  

  0-19- 
  

  

  0-0033- 
  

  

  (5) 
  

  

  5-10 
  

  

  4-97 
  

  

  0-13- 
  

  

  0-0022- 
  

  

  (6) 
  

  

  10-22 
  

  

  9 
  97 
  

  

  0-25 
  — 
  

  

  0-0043 
  — 
  

  

  (^) 
  

  

  10-21 
  

  

  9-97 
  

   With 
  Sodium 
  

  

  0-24 
  — 
  

   Thiosulphate. 
  

  

  0-0041- 
  ^ 
  

  

  (1) 
  

  

  5- 
  

  

  5-01 
  

  

  0-01 
  + 
  

  

  0-0002+ 
  'I 
  

  

  (2) 
  

  

  5- 
  

  

  4-99 
  

  

  0-01 
  — 
  

  

  0-0002 
  — 
  

  

  (3) 
  

  

  10- 
  

  

  10-02 
  

  

  0-02 
  + 
  

  

  0-0003 
  + 
  

  

  (4) 
  

  

  10-08 
  

  

  10-12 
  

  

  004 
  + 
  

  

  0-0007+ 
  J 
  

  

  The 
  action 
  of 
  arsenious 
  oxide 
  upon 
  Cerium 
  Dioxide 
  — 
  (with 
  

   Wm. 
  D. 
  Cutter). 
  

  

  The 
  fact 
  that 
  cerium 
  dioxide 
  is 
  reduced 
  by 
  hydriodic 
  acid 
  

   suggested 
  the 
  possibility 
  of 
  the 
  application 
  of 
  arsenious 
  acid 
  

   in 
  acid 
  solution 
  to 
  the 
  same 
  end 
  according 
  to 
  the 
  reaction 
  

  

  4CeO, 
  + 
  As,03 
  = 
  2Ce,03 
  + 
  AsA. 
  

   The 
  extreme 
  difficulty 
  with 
  which 
  the 
  ignited 
  cerium 
  dioxide 
  

   when 
  pure 
  dissolves 
  in 
  acids 
  has 
  already 
  been 
  mentioned, 
  and 
  

   for 
  this 
  reason 
  it 
  was 
  found 
  practically 
  impossible 
  to 
  obtain 
  

   any 
  results 
  by 
  this 
  method. 
  Weighed 
  portions 
  of 
  the 
  dioxide 
  

   were 
  placed 
  in 
  Erlenmeyer 
  beakers 
  with 
  an 
  excess 
  of 
  a 
  solution 
  

   of 
  arsenious 
  oxide 
  yV 
  ^' 
  10'°"' 
  of 
  (1 
  — 
  1) 
  sulphuric 
  acid 
  were 
  

   added, 
  and 
  the 
  boiling 
  continued 
  until 
  the 
  fuming 
  point 
  of 
  the 
  

   acid 
  was 
  reached 
  ; 
  but 
  even 
  at 
  this 
  point 
  only 
  a 
  partial 
  solution 
  

   of 
  the 
  dioxide 
  had 
  taken 
  place. 
  

  

  