﻿of 
  Mercury 
  as 
  Mercurous 
  Oxalate. 
  

  

  403 
  

  

  To 
  determine 
  the 
  amount 
  of 
  nitric 
  acid 
  that 
  may 
  be 
  present 
  

  

  in 
  the 
  titration 
  of 
  an 
  oxalate, 
  10 
  cm3 
  of 
  — 
  ammonium 
  oxalate 
  

  

  10 
  

  

  were 
  titrated 
  with 
  permanganate 
  at 
  a 
  dilation 
  of 
  100 
  cm3 
  with 
  

   sulphuric 
  acid 
  at 
  80° 
  C. 
  The 
  event 
  proved 
  that 
  10 
  cm3 
  of 
  nitric 
  

   acid, 
  sp. 
  gr. 
  1*15, 
  may 
  be 
  present 
  without 
  appearance 
  of 
  inter- 
  

   fering 
  action. 
  The 
  maximum 
  amount 
  of 
  nitric 
  acid 
  which 
  may 
  

   be 
  present 
  without 
  action 
  upon 
  the 
  mercurous 
  salt 
  was 
  deter- 
  

   mined 
  as 
  shown 
  in 
  the 
  following 
  experiments. 
  

  

  Excess 
  of 
  

  

  Hg 
  

  

  taken 
  as 
  

   Hg 
  2 
  (X0 
  3 
  ) 
  2 
  

   gras. 
  

  

  0-1122 
  

  

  f" 
  

   I 
  u 
  

  

  <« 
  

  

  I 
  

  

  I" 
  

  

  ammonium 
  

  

  

  

  

  

  oxalate 
  

  

  

  

  

  

  approximately 
  

  

  HN0 
  3 
  

  

  Volume 
  

  

  Hg 
  

  

  

  n 
  

  

  Sp. 
  gr. 
  1-15 
  

  

  at 
  

  

  found 
  

  

  

  — 
  cm 
  3 
  

   10 
  

  

  cm 
  3 
  

  

  precipitation 
  

  

  gms. 
  

  

  Error. 
  

  

  1'64 
  

  

  10 
  

  

  100 
  

  

  0-1087 
  

  

  — 
  0-0035 
  

  

  2*62 
  

  

  6 
  

  

  u 
  

  

  01098 
  

  

  — 
  0-0024 
  

  

  ]-59 
  

  

  6 
  

  

  u 
  

  

  0-1096 
  

  

  — 
  0-0026 
  

  

  1*53 
  

  

  5 
  

  

  a 
  

  

  0-1109 
  

  

  — 
  0-0013 
  

  

  1-40 
  

  

  5 
  

  

  a 
  

  

  0-1134 
  

  

  + 
  0-0012 
  

  

  1-50 
  

  

  5 
  

  

  a 
  

  

  0-1115 
  

  

  — 
  0-0007 
  

  

  1-70 
  

  

  4 
  

  

  u 
  

  

  0-1116 
  

  

  — 
  0-0006 
  

  

  1-59 
  

  

  8 
  

  

  200 
  

  

  0-1096 
  

  

  — 
  0-0036 
  

  

  6*62 
  

  

  8 
  

  

  u 
  

  

  0-1111 
  

  

  —o-ooii 
  

  

  7-72 
  

  

  8 
  

  

  u 
  

  

  0*1108 
  

  

  — 
  0-0014 
  

  

  2-59 
  

  

  5 
  

  

  It 
  

  

  0-1107 
  

  

  — 
  0-0015 
  

  

  2-07 
  

  

  5 
  

  

  ii 
  

  

  0-1003 
  

  

  — 
  0-0007 
  

  

  ( 
  " 
  

  

  ( 
  o-ioio 
  

  

  Working 
  under 
  the 
  conditions 
  stated 
  in 
  the 
  above 
  table, 
  it 
  is 
  plain 
  

   that 
  5 
  cm3 
  of 
  nitric 
  acid, 
  sp. 
  gr. 
  1*15, 
  may 
  be 
  used 
  before 
  its 
  solvent 
  

   action 
  is 
  sufficient 
  to 
  interfere 
  with 
  the 
  accuracy 
  of 
  the 
  process. 
  

   To 
  determine 
  the 
  amount 
  of 
  mercuric 
  salt 
  that 
  would 
  be 
  

   held 
  up 
  by 
  5 
  cm3 
  of 
  nitric 
  acid, 
  sp. 
  gr. 
  1*15, 
  the 
  following 
  experi- 
  

   ments 
  were 
  made. 
  

  

  Hg 
  

  

  

  Ammoninm 
  

  

  

  

  taken 
  as 
  

  

  HN0 
  3 
  

  

  i 
  , 
  n 
  

  

  

  

  Hg 
  2 
  (XO,) 
  9 
  

  

  Sp.gr. 
  115 
  

  

  oxalate 
  — 
  

  

  Volume 
  

  

  

  gms. 
  

  

  cm 
  3 
  

  

  cm 
  3 
  in 
  excess 
  

  

  cm 
  3 
  

  

  Time 
  before 
  precipitation. 
  

  

  0-0335 
  

  

  4 
  

  

  0-75 
  

  

  100 
  

  

  5 
  hours. 
  

  

  0-0095 
  

  

  4 
  

  

  1-00 
  

  

  100 
  

  

  No. 
  ppt. 
  20 
  hours 
  

  

  0-0143 
  

  

  5 
  

  

  6-5 
  

  

  100 
  

  

  u 
  

  

  0238 
  

  

  5 
  

  

  1-5 
  

  

  100 
  

  

  Slight 
  ppt. 
  20 
  hours 
  

  

  0-0238 
  

  

  5 
  

  

  5*5 
  

  

  100 
  

  

  25 
  minutes. 
  

  

  Five 
  cm 
  3 
  of 
  dilute 
  nitric 
  acid 
  (sp. 
  gr. 
  1*15) 
  will 
  prevent 
  the 
  pre- 
  

   cipitation 
  of 
  small 
  amounts 
  of 
  mercuric 
  salt, 
  10-20 
  mgms. 
  

   calculated 
  as 
  mercury, 
  depending 
  upon 
  the 
  amount 
  of 
  ammo- 
  

   nium 
  oxalate 
  present 
  in 
  excess. 
  This 
  amount 
  of 
  nitric 
  acid 
  

   has 
  no 
  apparent 
  solvent 
  action 
  on 
  a 
  precipitate 
  of 
  mercurous 
  

   oxalate 
  under 
  conditions 
  already 
  stated 
  and 
  does 
  not 
  interfere 
  

  

  