﻿Gooch 
  and 
  Walke?* 
  — 
  Analysis 
  of 
  Iodides. 
  

  

  297 
  

  

  normal 
  arsenious 
  acid 
  was 
  introduced 
  from 
  a 
  burette 
  to 
  the 
  

   bleaching 
  point, 
  5 
  cm3 
  of 
  starch 
  emulsion 
  were 
  added, 
  and 
  the 
  

   solution 
  was 
  titrated 
  back 
  with 
  decinormal 
  iodine 
  (usually 
  only 
  

   a 
  few 
  drops) 
  to 
  coloration. 
  

  

  

  

  

  Table 
  U. 
  

  

  

  

  

  

  Effect 
  of 
  Diluti 
  

  

  on. 
  

  

  

  

  

  

  

  Approximate 
  

  

  Volume 
  

  

  

  

  

  

  volume 
  upon 
  

  

  H 
  a 
  S0 
  4 
  (1:3) 
  

  

  

  KI 
  taken. 
  

  

  KI 
  found. 
  

  

  Error. 
  

  

  addition 
  of 
  H 
  2 
  S0 
  4 
  . 
  

  

  used. 
  

  

  

  grin. 
  

  

  grm. 
  

  

  grm. 
  

  

  cm 
  3 
  

  

  cm 
  3 
  

  

  0) 
  

  

  0-0772 
  

  

  0768 
  

  

  0-0004 
  — 
  

  

  150 
  

  

  5 
  

  

  (2) 
  

  

  0-0772 
  

  

  0-0765 
  

  

  0-0007 
  — 
  

  

  (< 
  

  

  (C 
  

  

  (3) 
  

  

  0-1544 
  

  

  0-1546 
  

  

  0-0002 
  + 
  

  

  « 
  

  

  a 
  

  

  (4) 
  

  

  0-1544 
  

  

  0-1541 
  

  

  0003 
  — 
  

  

  « 
  

  

  u 
  

  

  (5) 
  

  

  0-3087 
  

  

  0-3090 
  

  

  0-0003 
  + 
  

  

  M 
  

  

  a 
  

  

  (6) 
  

  

  0-3087 
  

  

  0-3088 
  

  

  0-0001 
  + 
  

  

  a 
  

  

  a 
  

  

  (<) 
  

  

  0-3859 
  

  

  0-3864 
  

  

  0-0005 
  + 
  

  

  u 
  

  

  a 
  

  

  (8) 
  

  

  0-3859 
  

  

  0-3860 
  

  

  o-oooi 
  + 
  

  

  a 
  

  

  (i 
  

  

  (9) 
  

  

  0-0772 
  

  

  0-0754 
  

  

  0-0018 
  — 
  

  

  300 
  

  

  5 
  

  

  (10) 
  

  

  0-0772 
  

  

  0-0757 
  

  

  0*0015 
  — 
  

  

  a 
  

  

  a 
  

  

  (11) 
  

  

  0-1543 
  

  

  0-1532 
  

  

  o-ooii 
  — 
  

  

  a 
  

  

  a 
  

  

  (12) 
  

  

  0-1544 
  

  

  0-1524 
  

  

  0-0020 
  — 
  

  

  u 
  

  

  (i 
  

  

  (13) 
  

  

  0-0772 
  

  

  0-0744 
  

  

  0-0028 
  — 
  

  

  500 
  

  

  5 
  

  

  (14) 
  

  

  0-0772 
  

  

  0-0737 
  

  

  0-0035 
  — 
  

  

  tt 
  

  

  u 
  

  

  (15) 
  

  

  01544 
  

  

  0-1521 
  

  

  0-0023 
  — 
  

  

  u 
  

  

  it 
  

  

  (16) 
  

  

  0-1544 
  

  

  0-i512 
  

  

  0-0032 
  — 
  

  

  (< 
  

  

  u 
  

  

  (17) 
  

  

  0-3859 
  

  

  03827 
  

  

  0-0032 
  — 
  

  

  (i 
  

  

  u 
  

  

  (18) 
  

  

  0-3859 
  

  

  0-3831 
  

  

  0-0028- 
  

  

  a 
  

  

  u 
  

  

  (19) 
  

  

  0-0772 
  

  

  0-0744 
  

  

  0-0028 
  — 
  

  

  500 
  

  

  10 
  

  

  (20) 
  

  

  0-0772 
  

  

  0-0757 
  

  

  0-0015- 
  

  

  u 
  

  

  a 
  

  

  (21) 
  

  

  0-3859 
  

  

  0-3828 
  

  

  0-0031 
  — 
  

  

  a 
  

  

  u 
  

  

  (22) 
  

  

  0-3859 
  

  

  0-3827 
  

  

  0-0032 
  — 
  

  

  « 
  

  

  ft 
  

  

  Blank 
  tests 
  made 
  upon 
  a 
  solution 
  obtained 
  by 
  mixing 
  the 
  

   maximum 
  amount 
  of 
  the 
  iodate 
  with 
  5 
  cmS 
  of 
  dilute 
  sulphuric 
  

   acid 
  (1:3), 
  neutralizing 
  as 
  usual 
  with 
  potassium 
  bicarbonate, 
  

   adding 
  the 
  iodide 
  from 
  the 
  trap 
  and 
  5 
  cm3 
  of 
  starch 
  emulsion, 
  

   showed 
  that 
  a 
  single 
  drop 
  of 
  iodine 
  was 
  invariably 
  sufficient 
  to 
  

   bring 
  out 
  the 
  starch 
  blue. 
  Occasionally 
  it 
  was 
  found 
  that 
  the 
  

   mixture, 
  particularly 
  when 
  chlorides 
  or 
  bromides 
  were 
  present, 
  

   of 
  itself 
  developed 
  a 
  trace 
  of 
  color, 
  but 
  by 
  no 
  means 
  a 
  read- 
  

   ing 
  tint. 
  A 
  correction 
  of 
  the 
  one 
  drop 
  of 
  iodine 
  necessary 
  

   to 
  bring 
  out 
  the 
  color 
  reaction 
  in 
  the 
  blanks, 
  was 
  applied 
  uni- 
  

   formly 
  in 
  the 
  analytical 
  process. 
  

  

  