141 



frequently f'i>rnif(I in other reactions, many of which we shall meet 

 with in the further course .if this work. It is. for instance, formed 

 by i lie action of water on suljiliur chlom It-, phosphorus chloride, anti- 

 ni ni y clili >ride, A:C. 



////'//"'7, '"i'r- >"-i>/ is a roll >urless u'a- havinu' a pungent suffocating 

 odour and an acid taste. This ^as fume- in ail 1 and attract-- moisture. 

 1 1"' -a use it forms ya pour contain in;: a compound of hydrochloric acid and 

 svatrr. 1 1 ydrochloric acid is lioiietied by cold, and under a pressure of 

 in atmosphere- into a colourless li.juid of .-p. ur. (H.MJS at d , :i ' boiling 

 point ">"' and absolute boiling point -f ~)'2. \\'c ha\r already seen 

 i ( 'hap. l.i t Itat 1 i\'d rod iloric acid comliines \'erv ener^vt icallv ///'/// ?/v///-/'. 

 and in >o doinu' c\ol\csa considei'able ainoiint of heat. 'J'he solution 

 saturateil in tin- cold attains a density 1 "2-\. On heatiiiLT such a solu- 

 tion containing ahoiit -I-"' ]>arts of acid per \()() parts, the hydrochloric 

 acid ua- i> expelled with only a slight admixture of aijueou^ \a])otir. 

 r.u' it is inipossilile to entirely separate the \\hole of the hydrochloric 

 acid tVoin the water liv thi> niean>, as could be done in the case of an 

 'a nn non iacal Dilution. The t emperal ure reijiiired foi 1 1 he e\ olut ion of the 

 L;';I- rises and reaches 1 lU 111, and after this remains constant that 

 i<. a >olution having a constant boiling point is obtained (p. !S), wliich. 

 howe\'er. doc> not ( Roscoe and I )ittmar) present a constant composition 

 under ditl'ei-eni pre^ures. because the hydrate is decomposed in distil- 

 lation, as is >een from the del erm in at ions of its \ a pour dens it v ( I Jineau ). 

 ) udu'ii r_: from the fact.- ( 1 i that \\ it 1 1 decrease* of the pressure under which 

 t he di-t illat ion proceed- the solution of constant boiling point ajiproaches 

 to a couipo-it ion of '2~> ]i.c. of hydrochloric acid. :i ' ('2) that bv passing a 

 -t ream of dr\- ;dr t hrouu'h a -olut ion of hydrochloric acid t here is obtained 

 in the residue a -olut ion which a!-o approaches to I 1 -' 1 p.c. of acid, more 

 nearl\' a- the t emj ,era t u re fa 1 ls. :! '' ( .'i i t hat man v of t he propert ies of solu- 

 1 ion - of hydrochloric acid varv dist i net I v according as t hey contain more 

 or Ies- than L'.'I p.c. of h\ drochloric acid (for instance, antimonious 

 -ulphide -i \ e- h\ droLTen sn !phide \\ it h a st roi i^er acid, but i- not acted 

 (in by a weaker solution, al.-o a stronger solution fume> in the air, 

 ,vc. ,, and ( I i that t he com} osil ion H ( '],G H .,( ) correspond.- with L'.ViM p.c. 



I' ilil-.-rl ;irl i. II. ,i \s,. ,ll;ill ;i 1 1 rl'\\ ; I H I - ( I. -( 'I'll ir . 



-H ti:.' i r. ..I i.Min.i liy.lniclil..rii- sicid at tl O'lHlM, at 

 .!. ( 'li.ij.i, ill. N,,),. :; i . 



I >;'::. - r ;il .1 HV- III . nl l]ir'f ;i t n K ,-, ,1 |i ]( - till' -' "111 tli H I 



