242  Observations  on  Decomposing  Chloroform.{Am^*;^vm- 
also  reacts,  but  faintly.  Still  following  the  decomposition,  it  is 
found  that  both  reagents  continue  to  give  marked  reactions  until  a 
point  is  reached,  when  that  produced  by  zinc  iodide  and  starch  is 
observed  to  become  less  marked,  and  finally  to  disappear  altogether, 
while  the  reaction  with  baryta  water  may  still  be  obtained.  A 
small  quantity  of  deep  straw-colored  liquid  is  also  observed  at  this 
stage  floating  on  the  surface  of  the  chloroform. 
At  this  point  there  remains  a  considerable  quantity  of  unde- 
composed  chloroform,  which  may,  either  before  or  after  separating 
the  decomposition  products,  be  again  put  into  an  active  state  of 
decomposition  by  simply  removing  the  stopper  from  the  bottle  for 
a  few  seconds,  replacing  it,  and  again  exposing  it  to  sunlight,  when 
reactions  similar  to  those  already  described  with  zinc  iodide  and 
starch  are  obtained.  This  result  has  been  reproduced  several  times 
with  about  a  dozen  different  samples  of  chloroform. 
Results  such  as  I  have  described  could  not  have  been  obtained  if 
Professor  Ramsay  is  correct  in  saying  that  carbonyl  chloride  and 
hydrochloric  acid  are  the  only  products  obtained  from  chloroform 
decomposing  in  the  presence  of  air. 
The  following  equations  supply  a  probable  explanation  of  the 
changes  observed,  although  they  do  not  explain  all  the  results 
obtained.  No  evidence  of  the  presence  of  carbon  tetrachloride 
having  been  found  in  the  products  is  certainly  a  weak  point,  but  it 
is  well  known  that  chlorine  and  chloroform,  when  brought  into 
contact,  produce  it,  and  it  will  be  seen  from  the  equations  that  the 
conditions  necessary  for  its  production  exist  in  the  early  stages  of 
decomposition. 
4CHCI3  -f  302  =  4C0C12  -f  2H20  +  2C12 
2COCl2  +  2H20  =  2C02  +  4HCI 
2CHCI3  -f  2C12  =  2CC14  +  2HCI 
6CHCI3  -f  302  =  2C0C12  +  2CC14  +  2C02-{-  6HC1 
In  support  of  this  view,  chlorine,  water  and  carbonyl  chloride  are 
found  in  the  early  stages,  the  chlorine  being  first  recognized,  and 
disappearing  with  the  water  at  a  more  advanced  stage,  and  in  the 
carbonyl  chloride  reaction  being  invariably  obtained,  not  only  in 
the  early  but  also  in  the  most  advanced  stage  met  with. 
The  time  required,  the  small  quantities  of  products  obtained  after 
waiting  for  months,  and  the  difficulties  to  be  faced  in  a  work's 
