﻿220 
  Gooch 
  and 
  Smith 
  — 
  Method 
  for 
  the 
  

  

  sodium 
  hydrate, 
  treated 
  with 
  an 
  excess 
  of 
  sodium 
  hydrogen 
  

   carbonate 
  amounting 
  to 
  20 
  cm. 
  3 
  of 
  the 
  saturated 
  solution, 
  

   cooled, 
  and 
  titrated 
  in 
  presence 
  of 
  starch 
  by 
  the 
  standard 
  

   iodine. 
  This 
  final 
  titration 
  gives, 
  of 
  course, 
  the 
  entire 
  amount 
  

   of 
  antimony 
  present. 
  The 
  difference 
  between 
  the 
  indications 
  

   of 
  the 
  two 
  titrations 
  is 
  the 
  measure 
  of 
  the 
  antimony 
  in 
  the 
  

   higher 
  condition 
  of 
  oxidation. 
  The 
  method 
  as 
  outlined 
  is 
  

   accurate 
  and 
  rapid, 
  and 
  so 
  simple 
  as 
  regards 
  manipulation 
  that 
  

   a 
  number 
  of 
  determinations 
  can 
  be 
  carried 
  through 
  simultane- 
  

   ously 
  with 
  the 
  use 
  of 
  ordinary 
  apparatus. 
  

  

  Art. 
  XX. 
  — 
  A 
  Method 
  for 
  the 
  Estimation 
  of 
  Chlorates; 
  

   by 
  F. 
  A. 
  Gooch 
  and 
  C. 
  G-. 
  Smith. 
  

  

  [Contributions 
  from 
  the 
  Kent 
  Chemical 
  Laboratory 
  of 
  Yale 
  College. 
  — 
  VII.] 
  

  

  It 
  has 
  been 
  shown 
  in 
  recent 
  work 
  in 
  this 
  laboratory* 
  that 
  

   under 
  conditions 
  properly 
  controlled, 
  arsenic 
  acid 
  in 
  excess 
  is 
  

   capable 
  of 
  expelling 
  the 
  iodine 
  from 
  hydriodic 
  acid 
  at 
  the 
  boil- 
  

   ing 
  temperature 
  of 
  the 
  solution, 
  being 
  itself 
  reduced 
  corres- 
  

   pondingly 
  according 
  to 
  the 
  equation 
  

  

  H 
  3 
  As0 
  4 
  + 
  2H-I 
  = 
  H 
  3 
  As0 
  3 
  + 
  H 
  2 
  + 
  I-I. 
  

  

  On 
  cooling 
  the 
  liquid 
  remaining 
  after 
  such 
  treatment, 
  and 
  

   neutralizing, 
  the 
  arsenious 
  oxide 
  produced 
  in 
  the 
  reaction 
  may 
  

   be 
  reoxidized 
  iodometrically 
  in 
  the 
  usual 
  manner, 
  the 
  iodine 
  

   added 
  to 
  accomplish 
  this 
  purpose 
  being 
  the 
  exact 
  measure 
  of 
  

   the 
  iodine 
  originally 
  present 
  as 
  hydriodic 
  acid 
  and 
  expelled 
  

   from 
  the 
  acid 
  solution 
  during 
  the 
  process 
  of 
  boiling. 
  

  

  If 
  other 
  sufficiently 
  energetic 
  and 
  easily 
  decomposable 
  ox- 
  

   idizing 
  agents 
  are 
  present 
  at 
  the 
  same 
  time 
  with 
  the 
  arsenic 
  

   acid, 
  it 
  would 
  be 
  natural 
  to 
  suppose 
  that 
  these 
  substances 
  will 
  

   act 
  similarly 
  upon 
  the 
  hydriodic 
  acid, 
  and, 
  furthermore, 
  that 
  

   the 
  oxidizing 
  power 
  of 
  the 
  arsenic 
  acid 
  will 
  not 
  be 
  called 
  into 
  

   play 
  until 
  that 
  of 
  the 
  more 
  unstable 
  oxidizers 
  has 
  been 
  ex- 
  

   hausted. 
  Chloric 
  acid, 
  for 
  example, 
  acts 
  with 
  great 
  ease 
  upon 
  

   hydriodic 
  acid, 
  and 
  it 
  would 
  be 
  natural 
  to 
  suppose 
  that 
  in 
  a 
  

   mixture 
  of 
  chloric, 
  hydriodic 
  and 
  arsenic 
  acids 
  the 
  mutual 
  

   action 
  of 
  the 
  chloric 
  and 
  hydriodic 
  acids 
  will 
  be 
  manifest 
  first 
  

   and 
  will 
  go 
  on 
  steadily 
  to 
  completion, 
  and 
  that 
  when 
  this 
  effect 
  

   is 
  accomplished, 
  and 
  then 
  only, 
  the 
  action 
  of 
  the 
  arsenic 
  acid 
  

   in 
  liberating 
  iodine 
  from 
  the 
  residual 
  hydriodic 
  acid 
  and 
  in 
  

   registering 
  by 
  its 
  own 
  reduction 
  the 
  amount 
  of 
  iodine 
  thus 
  set 
  

   free 
  will 
  appear. 
  It 
  should 
  be 
  possible, 
  therefore, 
  if 
  this 
  

   theory 
  of 
  the 
  reaction 
  between 
  these 
  substances 
  is 
  correct, 
  to 
  

   found 
  upon 
  the 
  method 
  referred 
  to 
  for 
  the 
  estimation 
  of 
  iodine 
  

  

  * 
  Gooch 
  and 
  Browning; 
  this 
  Journal, 
  xxxix, 
  p. 
  188. 
  

  

  