ࡱ > D F C h bjbj . cch $ $ k k k k k $ 4 Z \ \ \ \ \ \ $ k k k k k Z Z IK j F 0 U! R $ U! U! k ` Z @ 4 4 h v p U! $ 1 : TOPIC 12 ANSWERS TO EXERCISES Topic 12 Exercise 1 1. a) acid b) both c) acid d) both e) base f) base g) both h) both i) both j) both k) both 2. a) H2O b) HClO4 c) HSO4- d) H3O+ 3. a) HCO3- (acid) and CO32- (base), H2O (base) and H3O+ (acid) b) HCO3- (base) and CO2 + H2O (acid), H3O+ (acid) and H2O (base) c) H2SO4 (acid) and HSO4- (base), HNO3 (base) and NO2+ + H2O (acid) d) HSO4- (acid) and SO42- (base), OH- (base) and H2O (acid) Topic 12 Exercise 2 1. a) 3.00 b) 11.30 c) 2.60 d) 4.89 e) 1.65 f) 12.60 2. a) 1.0 x 10-3 moldm-3 b) 6.3 x 10-3 moldm-3 c) 1.0 x 10-3 moldm-3 3. 2.0 x 10-5 moldm-3 4. 76 Topic 12 Exercise 3 1. a) resists large pH change on addition of small amounts of acid or alkali b) 4.60 c) CH3CH2COOH + OH- ( CH3CH2COO- + H2O CH3CH2COO- + H+ ( CH3CH2COOH d) 4.84 e) 4.30 f) 12.30 g) the buffer solution restricts the pH change to 0.24 units, but the water changes its pH by 5.30 units (from 7 to 12.3). 2. a) 2.85 b) 3.33 g c) 4.41 d) 4.77 3. 8.65 4. salt: acid ratio 1.58:1 5. a) 10.21 b) 10.01 c) 10.54 d) 13.00 e) buffering capacity has been exceeded, so cannot resist change in pH. Topic 12 Exercise 4 1. a) i) 2.37 ii) 3.27 iii) 3.74 iv) 4.22 v) 11.85 b) c) the salt produced is sodium methaoate, and the methanoate ion is basic: HCOO- + H2O ( HCOOH + OH- 2. a) 1.70 b) 12.30 3. a) b) c) d) 4. a) methyl red, as it will change colour completely within the pH range (4 7), over which the equivalence point occurs b) both, as they will both change colour completely within the pH range (4 10), over which the equivalence point occurs c) phenolphthalein, as it will change colour completely within the pH range (7 10), over which the equivalence point occurs d) neither, as there is no sharp pH change at the equivalence point of this titration, so indicators will not change colour sharply ' 3 4 7 b $ % & ' 4 5 ? üñ hT H*mHsHh* H*mHsHh* mHsH h* h* H*mHsHh* h* mHsH h* h* h* h* mH sH h0b h* 5mH sH h@q 5mH sH hD0 5mH sH h* 5mH sH h_I 5mH sH 3 3 4 c > U k q r gdT `gdT `gd* gd* $a$gd* $a$gdD0 ? C D F G V W X d e s t u y z & ( 4 6 < > ? J L R T U ` b h j k r z мפפפפלפלה h_I 5mHsHh* mHsH hT mHsH hT hT mHsH h0b hT 5 h_I 5hT hT hT H*hT hT H*hT h* hT H*mHsHhT H*mHsHh* hT H*mHsHhT h* mHsH3z u v w h} hT j h} h} UhwJ hT h h0b hZ% 5 h_I 5h} hZ% j h: h: h: H*h: h: H*h: hT hT hT hT mHsH h0b hT 5mHsH 9 $ @ , u w 0 1 F G T Z e ^`gdX ^`gdwJ gd: 0^`0gd: gd* " # . / 0 1 T U X Y Z d e f g h k l m . V g h ⺳Ө h hI^ h_I h* j[ h h Uh j hX h UhT h* hT h} hX h} j hX hX UhX jN hX hX Uh} hT j hwJ h} H*hwJ h} H* e m n d f g h gd 0^`0gd ^`gd 0^`0gd gd* , 1h/ =!"#$% N D d !cc 0 # A " l$k1c D @= l$k1c! < ,"S }; l xZ}LU˅V䀠nlSUh!h6'b]ѹf,>*JlƜq}0?y\s?ku> TIJ[ {HtY W@#q0ETl~ְ]PH QQ.GHC= E$R,d m3\0fԳ=}벟 MQ}:###p;SQRXQSYE^FVX +{ީ_0(lGer[,ƈ_ݍ٣#BgźZܯZor+?eg2HPaWrjW)?z}\NXμ9l9Wڶ?t@,FlEqcNuxP͖C5 )䁎Ё.O[Ⱦw]:WP+]>UɵQj*]Qq9Ɔ{ ad?d7=z?9죯7OZ`E---"!UX?x,DIo ,,!dY$ŢHR+W}wX;_՟^_!Ț Q=:?Jۅ`gix_b];5Sh j /" "U+r|T4D~Fh\1gߡ;4pjO}:LpKDi^%.*s ָ5t67Pa$ċ5 p= _]6{x~pA>(p,laep8 yb=}u}+e=\ ]P%:mQ^'Chhq&g>Jp朝wQm(/^E1[cSl]Y-V+b%e]6`(7q4>OqG]U7m]uۑR%n妦Jʖj|3[LcgZ 9/@x<gs0pEo8G9_,Ge#sip wwQDF0Děs+TpM< ZJl"Mc258%v5b/j퍐7K+ps >B<ox"gr|gYy%f|:'oDf6]aܨ:!Ɛ&f- A:_Mh]o?PVߧh.Mwke2Ewfx~7{BcH`9){k( XtSp[9To}>*+Ot<_= Q{ $s{;scm|%E>#N⧇vď}K)gpK=e7#<=6KyXޘOUS,ݼW.yv?oo#+a ^{L7CMDz5Phݻ}!}lM3=z#K9L}y*p>U8},V+y.F?x6 D d ! 0 # A " Wj}X @= Wj}X < ,"S }; T xYolTEyrR@`H