﻿Peters 
  — 
  Separation 
  and 
  Determination 
  of 
  Mercury. 
  401 
  

  

  A 
  kt. 
  XXXIX. 
  — 
  The 
  Separation 
  and 
  Determination 
  of 
  Mer- 
  

   cury 
  as 
  Mercurous 
  Oxalate 
  ; 
  by 
  C. 
  A. 
  Peters. 
  

  

  [Contributions 
  from 
  the 
  Kent 
  Chemical 
  Laboratory 
  of 
  Yale 
  University 
  — 
  XCI 
  V.] 
  

  

  It 
  is 
  stated 
  in 
  the 
  literature* 
  that 
  oxalic 
  acid, 
  neutral 
  and 
  

   acid 
  oxalates 
  of 
  the 
  alkalies, 
  precipitate 
  mercurous 
  salts, 
  and 
  

   that 
  oxalic 
  acid 
  and 
  the 
  double 
  oxalates 
  of 
  potassium 
  produce 
  

   no 
  precipitate 
  with 
  mercuric 
  chloride 
  solution. 
  Starting 
  with 
  

   these 
  facts, 
  the 
  attempt 
  was 
  made 
  to 
  estimate 
  mercurous 
  salts 
  : 
  

   volu 
  metrically, 
  by 
  precipitating 
  with 
  ammonium 
  oxalate 
  and 
  

   determining 
  the 
  oxalic 
  acid 
  by 
  potassium 
  permanganate 
  ; 
  and 
  

   gravimetrically 
  by 
  direct 
  weighing 
  of 
  the 
  precipitate. 
  

  

  The 
  Volumetric 
  Estimation. 
  

  

  The 
  mercurous 
  nitrate 
  solution 
  used 
  was 
  standardized 
  by 
  the 
  

   battery, 
  and 
  contained 
  about 
  12 
  gins, 
  of 
  metallic 
  mercury 
  to 
  

   the 
  liter. 
  To 
  obviate 
  the 
  tendency 
  of 
  the 
  mercury 
  salt 
  to 
  

   break 
  down 
  and 
  form 
  basic 
  saltsf 
  upon 
  the 
  addition 
  of 
  a 
  large 
  

   amount 
  of 
  water 
  if 
  no 
  nitric 
  acid 
  is 
  added, 
  the 
  solution 
  was 
  

   prepared 
  in 
  the 
  following 
  manner. 
  About 
  20 
  gms. 
  of 
  mercu- 
  

   rous 
  nitrate 
  were 
  ground 
  in 
  a 
  mortar, 
  transferred 
  to 
  a 
  flask, 
  

   and 
  200-300 
  cm3 
  water 
  added. 
  After 
  shaking 
  well, 
  the 
  solu- 
  

   tion 
  was 
  filtered 
  and 
  the 
  filtrate 
  diluted 
  to 
  one 
  liter. 
  Five 
  cm 
  3 
  

   of 
  this 
  solution 
  when 
  precipitated 
  with 
  a 
  sodium 
  chloride 
  

   solution 
  gave 
  a 
  filtrate 
  from 
  which 
  only 
  a 
  very 
  slight 
  darken- 
  

   ing 
  in 
  color 
  could 
  be 
  obtained, 
  even 
  upon 
  several 
  hours 
  

   standing, 
  when 
  treated 
  with 
  hydrogen 
  sulphide, 
  thus 
  showing 
  

   the 
  absence 
  of 
  a 
  mercuric 
  salt. 
  

  

  A 
  solution 
  made 
  in 
  the 
  above 
  manner 
  had 
  not 
  changed 
  its 
  

   standard 
  after 
  a 
  period 
  of 
  eight 
  weeks. 
  The 
  potassium 
  per- 
  

  

  Yl 
  

  

  manganate 
  solution 
  (approximately 
  — 
  ) 
  was 
  standardized 
  against 
  

  

  lead 
  oxalate. 
  

  

  It 
  was 
  first 
  attempted 
  to 
  estimate 
  the 
  mercurous 
  salts 
  as 
  

   follows. 
  The 
  mercurous 
  oxalate 
  was 
  precipitated 
  cold 
  by 
  

   means 
  of 
  ammonium 
  oxalate, 
  stirred 
  well, 
  and 
  allowed 
  to 
  

   settle, 
  the 
  completion 
  of 
  the 
  precipitation 
  being 
  determined 
  

   by 
  addition 
  of 
  more 
  ammonium 
  oxalate. 
  The 
  precipitate 
  was 
  

   collected 
  on 
  asbestos, 
  washed 
  once 
  or 
  twice 
  with 
  cold 
  water, 
  

   and 
  (still 
  in 
  the 
  crucible) 
  treated 
  in 
  a 
  beaker 
  with 
  5 
  cm3 
  of 
  

   strong 
  hydrochloric 
  acid. 
  To 
  the 
  solution 
  diluted 
  to 
  100-200 
  cm3 
  

   1 
  gin. 
  of 
  a 
  manganous 
  salt 
  was 
  added, 
  and 
  the 
  oxalic 
  

   acid 
  was 
  titrated 
  with 
  permanganate 
  at 
  the 
  ordinary 
  tem- 
  

   perature 
  of 
  the 
  room. 
  The 
  end 
  color 
  was 
  not 
  stable 
  and 
  

   was 
  hard 
  to 
  determine. 
  Three 
  experiments, 
  using 
  0-1217 
  of 
  

  

  *Rose 
  unci 
  Finkener. 
  Handbuch 
  der 
  Analytischen 
  Chemie, 
  i, 
  319. 
  

   f 
  Graham 
  Otto, 
  Handbuch, 
  iii, 
  1102. 
  

  

  