HYDROG1 \ |. 27 



"I .\ IK 'I thai is, a hj drochloric acid -■ 

 of the molecular weighl «>r hydrochl cid in 



liter of water. At this dilution HC1 is 91 p< 



t!i«' II ion concenl rati ,r <*,, ,-is ir i itten 



or, in mathemal ical notal ion, 9.1 I' 1 



Mi thod of I' ■■■ I To '• "i'l the 



several figures t<> express C ... as has Keen done abo 



• In ! a scheme by which only one figuri l 



ignated by Ph, is Pound by subtracting from the i 



the figure standing behind I 11 the common logarithm • 



pressing the normality of the acid.* In a decinormal II" 



therefore, we must subtracl from the po 



which is .96 ascertained from logarithm tabl< 1 "I T 



another example: decinormal acetic acid is dissociate 



tent of 1.3 per cent; C H is therefore 0.0013 normal, or 1.3x1 



the logarithm of 1.3 is .11, P„ equals 3 .11, •■ 2 - 



The only objection to the use of tl onenl Ph aa 



the B-ion concentration is that it inc in magn 



becomes less; this is because the negati 

 garded. As stated above, it is usual t<» express tl 

 .is well as acids in terms of Ch, or Ph, becaus 

 concentration of II ions than of <'II ioi - A. 0.1 NaOB s 

 per cenl dissociated; therefore the "OH" ion is 



equivalents n|| per liter . and since the produd 1 Oil' 



concentrations must always equal 1" I 20 I 



the II ion increases in concentration, the "'11 i<»u m 

 crease. ESxpressed according t<> the above Bchemt SM \ KaOIl 



solution gives P H L3.06; thus, 0.084 B.4xl0 8 ; 

 and this subtracted from the power 2 1.08 P 14.14 



L3.06 as P H . ## 



similar]}. I\, of "'.1 \ Ml HO solution is 11.286 It* 

 1 } per cent ; therefore the solution contaii 

 HO i.e., M L0 P l 16 2 B54 P 14.1 



11.286.1 



'"It !■ 



ihai number 

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