Avtoprotolız. Sýtektik kórsetkish

Ońtústik Qazaqstan obylysy
Shardara aýdany
№ 16 kolej stýdenti   
Oryndaǵan: F-40 top stýdenti Ámir Nurjan Anarbekuly

 

Avtoprotolız reaksıasy barysynda birtúrli eritkish molekýlalarynyń biri protonyn berip, ekinshisi ony qosyp alyp tepe-teńdik ornaıtyndyǵyn addyńǵy taqyryptan habardar boldyq, ıaǵnı:

H₂O+H₂O ⇔H₃O⁺+OH^-

NH₃+NH₃ ⇔ NH⁺₄+NH^-₂

CH₃OH+CH₃OH ⇔CH₃OH₂⁺ CH₃O^-

Jalpy jaǵdaı úshin:

HSolv+HSolv ⇔H₂Solv⁺+Solv^-

Tepe-tendikti sandyq tuǵyda sıpattaý úshin tepe-teńdik konstanta órnegin jazalyq:    

K=[H₃O⁺]*[OH^-]/[H₂O]*[H₂O]

K=[H₂Solv⁺]*[Solv^-]/[HSolv]*[HSolv]

Dıssosıasıalanýǵa eritkish molekýlasynyń óte az bóligi ushyraıtyn bolǵandyqtan onyń konsentrasıasyn turaqty dep qabyldaımyz da, tepe-teńdik konstantasyna kóbeıtip jiberemiz:

K*[H₂O]²=K_w=[H₃O⁺]*[OH^-]

K*[HSolv]=K_HSolv=[H₂Solv⁺]*[Solv^-]

Teńdeýlerdiń birinshisi kádimgi ózimizge tanys sýdyń ıondyq kóbeıtindisi. Ekinshi teńdeý de eritkishtiń nemese lıonı - lıat ıondarynyń kóbeıtindisi jáne K_HSolv - shamasy avtoprotolız konstantasy dep atalady.

Bólme temperatýrasy (~25°S) jaǵdaıynda sýdyń ıondyq kóbeıtindisiniń máni 1*10^-14 -ke teń, ıaǵnı

K_w=[H₃O⁺]*[OH^-]=1*10^-14

Teńdikten [H₃O⁺]=[OH^-]  jaǵdaıynda [H⁺] shamasyn anyqtalyq:

Jazylý qarapaıym bolý úshin jáne ózimizge burynnan kóztanys H₃O⁺ ornyna H⁺-ti paıdalansaq [H⁺]=10^-7mol/l

Qoldanýǵa yńǵaıly bolý úshin ondyq logarıfm júıesin paıdalanyp -lg[H⁺] ≈ pH, al -lg[OH^-] ≈ pOH  dep belgilep, bulardy sýtektik jáne negizdik kórsetkish dep ataıdy. Sýdaǵy eritindiler úshin onyń rN mánine qaraı ortany beıtarap, qyshqyldy jáne negizdik dep úshke bóledi.

1. [N⁺] = [ON^-] = 10^-7 mol/l, rN = 7, orta beıtarap.

2. [N⁺] > [ON^-]; [N⁺] >10^-7 mol/l, rN < 7 qyshqyldy orta.

3. [N⁺] < [ON^-]; [N⁺] <10^-7  mol/l, rN > 7 siltili orta.

Eger,  pH+pOH=14 ekendigin eskersek kez-kelgen sýdaǵy eritindi úshin sýtektik kórsetkish máni tómendegishe anyqtalady:

pH=14-pOH

Aıtqandarymyzdy jalpy eritkishter men sý úshin jazatyn bolsaq tómendegideı órnek alamyz:

Eritkish sý                                                   Amfıprotondy eritkish

H₂O ⇔ H⁺+OH^-                                                       HSolv ⇔ H⁺+Solv^-  

nemese                                                       nemese

2H₂O ⇔ H₃O⁺+OH^-                                                   2HSolv ⇔ H₂Solv⁺+Solv^- 

K_w=[N⁺] *[ON^-]                                            K_HSolv=[N] *[Solv^-]

nemese                                                       nemese

K_w=[N₃O⁺] *[ON^-]                                       K_HSolv=[N₂Solv⁺] *[Solv^-]

pK_w=pH+pOH                                             pK_HSolv=pH+pSolv

[N⁺]=[ON^-]                                                   [N]=[Solv^-]

pH=1/2pK_w     <— Beıtarap orta—>              pH=1/2pK_HSolv

[N⁺]>[ON^-]                                                     [N]>[Solv^-]

pH<7          <— Qyshqyldyq orta —>             pH<pSolv

[N⁺]<[ON^-]                                                     [N]<[Solv^-]

pH>7          <— Siltilik orta —>                    pH>pSolv

Qyshqyldyq ortany kórsetetin shkala sý úshin 0 men 14 aralyǵynda jatsa, ózge eritkish úshin "0" den pK_HSolv aralyǵn alady. Amfıprotondy keıbir eritkishterdiń avtoprotolızi 1 - kestede keltirilgen

Amfıprotondy eritkishterdiń avtoprotolızi

Eritkish HSolv	Lıonı H2Solv+	Lıat Solv-	KHSolv	pH shkalasy	Beıtarap orta máni pH=1/2 pKHSolv
H2O	H3O+	OH-	10-14	0-14,0	7
H2SO4	H3SO+4	HSO-4	10-3,6	0-3,6	1,8
HCOOH	HCOOH+2	HCOO-	10-6,7	0-6,7	3,35
CH3COOH	CH3COOH	CH3COO-	10-14,4	0-14,4	7,2
CH3OH	CH3OH+2	CH3O-	10-17,3	0-17,3	8,65
C2H5OH	C2H5OH+2	C2H5O-	10-19	0-19,0	9,5
NH3	NH+4	NH-2	10-22	0-22	11,0
CH3-CN	CH3CNH+	CH3CN-	10-19,5	0-19,5	9,75

Demek, kez-kelgen eritkish úshin, orta qyshqyldyǵy nemese siltiligin lıonı nemese lıat ıondarynyń konsentrasıasymen (aktıvtiligimen) sıpattaýǵa bolady. Qoldanýda yńǵaıly bolý úshin, kádimgi ózimizge tanys pH jáne pOH sıaqty  pH jáne p[Solv^-] mánderin paıdalanady.   Mundaǵy pH jáne pOH  - sýtektik jáne negizdik kórsetkish bolyp atalatyndyqtan jalpy jaǵdaı úshin, p[Solv^-]-te negizdik kórsetkish bolyp atalady.

Esimizge túsirelik!

Sý úshik, K_w=[H⁺]* [OH^-];   pK_w=pH+pOH;

Eritkish úshin, K_HSolv=[H]* [Solv^-];  p K_HSolv=pH+pSolv; .

Eger,  pH=0 bolsa, onda pOH=pK_w jáne p[Solv^-]=p K_HSolv  Al, pOH=0 bolsa, onda pH=pK_w jáne pH=pK_HSolv.

Demek, eritkish qyshqyldyǵyn sıpattaıtn sýtektik kórsetkish "0" den pK_HSolv (sý úshin 0 den 14-ke deıin) deıingi aralyqta jatady.

Mundaǵy K_HSolv - kádimgi sýdyń ıondy kóbeıtindisi K_H2O ispettes eritkishtiń ıondyq kóbeıtindisi nemese avtoprotolız konstantasy dep atalady.

Eritkishterde pH máni temperatýraǵa da kóp baılanysty. Mysaly, temperatýraǵa qaraı sý úshin pK_w  máni tómendegishe ózgeredi.

1°S         0          22         50           80          100

pK_w       14,82    14,00    13,26      12,60      12,26

Eger bólme temperatýrasynda beıtarap orta úshin  pH-máni 7,00 bolsa, 100°S úshin bul mán 6,13 -ti quraıdy.

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