CHLC'EIC  ACID.  HCIO3.  Syn.  Hypee-
oxymueiat'io  acid  ;  AOIDITM  CHLO"BICiriI,
L.  An  acid  discovered  by  Chenevix,  but
first  obtained  in  a  separate  form  by  Gay-
Lussac.
CHLC'EIDE  (-)d).  Syn.  CHLo"BUEETt;
Chloei'dum,  L.  a  chemical  compound  of
chlorine  with  a  metal  or  other  basic  radical,
e.g.  NaCl,  chloride  of  sodium  j  C2H5CI,  chloride
of  ethyl.
Prep.  The  majority  of  the  metallic  chlorides
may  be  made  by  simply  dissolving  the  metal
or  its  carbonate,  oxide,  or  hydrate,  in  hydro-
chloric acid  (previously  diluted  with  about
twice  its  weight  of  water),  and  evaporating
and  crystallising  the  solution  in  the  usual
manner.  Zinc,  cadmium,  iron,  nickel,  cobalt,
and  tin,  dissolve  readily  in  hydrochloric  acid ;
copper  only  in  strong  boiling  acid ;  silver,
mercury,  and  gold,  not  at  all.  The  insoluble
chlorides,  as  those  of  silver  and  mercury,  may
be  readily  prepared  bv  precipitating  any  of
their  corresponding  soluble  salts  with  hydro-
chloric acid,  or  a  soluble  chloride,  such  as
common  salt.  Anhydrous  chlorides  are  gene-
rally prepared  by  the  direct  action  of  chlorine
on  the  bases.
Char.,  Tests,  S;e.  Most  of  the  metallic
chlorides  ai'e  soluble  in  water.  Many  fuse
when  heated,  and  volatilise  unchanged,  but
others  are  completely  or  partially  decomposed
at  a  red  heat.  All,  with  the  exception  of  those
of  the  alkali  and  earth  metals,  are  decomposed
at  a  red  heat  in  a  current  of  hydrogen.  They
are  recognised  by  the  following  reactions  : — 1.
