2.2. CC dung dch chun (C)

 

Quy nh chung

Dung dch chun l dung dch c nng chnh xc bit trc dng trong phn tch nh lng th tch.

Nng ca dung dch chun thng c biu th bng:

Nng ng lng gam (N): S ng lng gam ca cht tan trong 1000 ml dung dch.

Nng mol (M): S mol ca cht tan trong 1000 ml dung dch.

T s gia nng thc v nng l thuyt l h s hiu chnh K, khng c nm ngoi gii hn 1,00 0,10. Nn dng cc dung dch chun vi K trong khong 0,970 - 1,030. Nng dung dch chun c xc nh vi s ln chun thch hp v lch chun tng i ca cc kt qu thu c khng c qu 0,2%.

Phng php chung pha ch cc dung dch chun

Đối với mỗi loại dung dịch chuẩn độ, phương php pha chế v chuẩn ho những dung dịch ở cc nồng độ hay được sử dụng nhất sẽ được m tả dưới đy. Cc dung dịch đậm đặc hơn được pha chế v chuẩn ho bằng cch tăng lượng thuốc thử ln tương ứng. Cc dung dịch nước c nồng độ long hơn được điều chế bằng cch pha long chnh xc một dung dịch đậm đặc hơn với nước khng c carbon dioxyd (TT). Hệ số hiệu chỉnh của những dung dịch ny chnh l hệ số hiệu chỉnh của dung dịch đ dng để pha long. Cc dung dịch nước c nồng độ mol nhỏ hơn 0,1 M phải được pha chế với nước khng c carbon dioxyd (TT).

Khi pha chế cc dung dịch km bền vững như kali permanganat, natri thiosulfat, phải dng nước mới đun si để nguội. Đối với dung dịch chuẩn độ được dng trong định lượng m điểm tương đương được xc định bằng phương php điện ho th kỹ thuật xc định điểm tương đương ny cũng phải được dng trong chuẩn ho dung dịch đ

Tt c cc dung dch chun phi c pha ch, chun ho v s dng nhit 25 0C. Nu nhit khi nh lng khc vi nhit lc chun ho th th tch dung dch chun s c hiu chnh li.

Di y l phng php pha ch v chun ho cc dung dch chun c dng trong Dc in:

Pha ch t cht chun gc

Cn chnh xc mt lng cht chun gc tng ng vi lng cht l thuyt tnh theo nng v th tch dung dch chun cn pha, ho tan trong dung mi ch dn va th tch.

Pha gn ng ri chun ho bng cht chun gc hoc bng dung dch chun c h s K bit

Cht chun gc: Cc ho cht loi tinh khit phn tch di y, sau khi lm kh trong nhng iu kin ch dn, c dng lm cht chun gc xc nh K ca dung dch chun :

Acid benzoic (C7H6O2): 24 gi trong bnh ht m cha silicagel khan.

Acid sulfanilic (C6H7NO3S): Sy 100 105 0C n khi lng khng i.

Arsen trioxyd (As2O3): 24 gi trong bnh ht m cha silicagel khan.

Kali bromat (KBrO3): Sy 180 0C n khi lng khng i.

Kali dicromat (K2Cr2O7): Sy 150 0C n khi lng khng i.

 

Kali hydrophtalat (C8H5O4K): Sy 110 0C n khi lng khng i.

Kali iodat (KIO3): Sy 130 0C n khi lng khng i.

Km ht (Zn): S dng loi c hm lng Zn khng t hn 99,9%.

Natri carbonat khan (Na2CO3): Sy kh 270 300 0C n khi lng khng i.

Natri clorid (NaCl): Nung 300 0C n khi lng khng i.

Cch xc nh K:

Chun ho bng cht chun gc: Cn chnh xc mt lng cht chun gc, ho tan trong dung mi ch dn, chun bng dung dch chun mi pha, tnh K theo cng thc:

a

K = (1)

T.V

 

Trong :

a: Lng cht chun gc cn (g).

T: chun l thuyt ca cht chun gc (g/ml).

V: S ml dung dch chun dng.

Chun ho bng dung dch chun c h s K0 bit.

Trong trng hp ny, K c tnh theo cng thc:

 

V0.K0.Co

K = (2)

V. C

Trong :

C0: Nng l thuyt ca dung dch chun dng chun ho.

K0: H s hiu chnh ca dung dch chun dng chun ho.

V0: S ml dung dch chun dng chun ho dng.

C: Nng l thuyt ca dung dch chun cn pha.

V: S ml dung dch chun cn xc nh h s K dng.

Ch thch:

Nu K nm ngoi gii hn quy nh, cn pha long hay lm m c dung dch. Khi cn pha long, tch (K - 1) nhn vi 1000 l s ml dung mi cn thm vo 1000 ml dung dch. Trong trng hp cn lm m c, tch (1 - K) nhn vi s g ho cht cn ly pha 1000 ml dung dch l s g ho cht phi thm vo 1000 ml dung dch. Sau khi thm dung mi hay ho cht, xc nh li K ca dung dch thu c.

Dng ng chun pha sn

ng chun pha sn (fixanal) cha lng ho cht hay dung dch ho cht pha thnh mt th tch dung dch chun quy nh. Dng dung mi pha ch theo ch dn ghi trn nhn ng, thu c dung dch chun c K = 1,000.

Cch pha ch mt s dung dch chun

Dung dch acid acetic 0,1 N

1 ml dung dch cha 0,00601 g acid acetic (C2H4O2).

iu ch: Ly 6,0 g acid acetic bng (TT) pha long vi nc va 1000 ml.

Chun : Ly 25,0 ml dung dch acid acetic iu ch, chun bng dung dch natri hydroxyd 0,1N (C), dng 0,5 ml dung dch phenolphtalein (TT) lm ch th.

H s hiu chnh c tnh theo cng thc (2).

Dung dch acid hydrocloric 1 N

1 ml dung dch cha 0,03646 g acid hydrocloric (HCl).

iu ch: Ly 85 ml acid hydrocloric m c (TT) pha long vi nc va 1000 ml.

Chun : Cn chnh xc khong 0,50 g cht chun gc natri carbonat, ho tan trong 50 ml nc, thm 2 git dung dch da cam methyl (TT). Chun bng dung dch acid hydrocloric iu ch cho n khi chuyn sang mu hng cam. un si 2 pht, ngui, chun tip n mu hng cam.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,053 g/ml.

Dung dch acid hydrocloric 0,5 N

1 ml dung dch cha 0,01823 g acid hydrocloric (HCl).

iu ch: Ly 42 ml acid hydrocloric m c (TT) pha long vi nc va 1000 ml.

Chun : Tin hnh nh m t trong Dung dch acid hydrocloric 1 N, dng khong 0,25 g (cn chnh xc) cht chun gc natri carbonat.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,0265 g/ml.

Dung dch acid hydrocloric 0,1N

1 ml dung dch cha 0,003646 g acid hydrocloric (HCl).

iu ch: Ly 8,5 ml acid hydrocloric m c (TT) pha long vi nc va 1000 ml.

Chun : Tin hnh nh m t trong Dung dch acid hydrocloric 1 N, dng khong 0,10 g (cn chnh xc) cht chun gc natri carbonat.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,0053 g/ml.

Dung dch acid hydrocloric 0,1 N trong methanol

1 ml dung dch cha 0,003646 g acid hydrocloric (HCl).

iu ch: Ly 8,5 ml acid hydrocloric m c (TT) pha long vi methanol (TT) va 1000 ml.

Chun : Tin hnh nh m t trong Dung dch acid hydrocloric 0,1 N.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,0053 g/ml.

Dung dch acid percloric 0,1 N

1 ml dung dch cha 0,01005 g acid percloric (HClO4).

iu ch: Ly 900 ml acid acetic bng (TT), thm 8,5 ml acid percloric (TT), trn u v thm 30 ml anhydrid acetic (TT). Thm acid acetic bng (TT) va

1000 ml. Lc u, yn 24 gi. Xc nh hm lng nc theo Ph lc 10.3 m khng thm methanol, v nu cn th iu chnh hm lng nc trong khong 0,1 - 0,2% bng anhydrid acetic hoc nc. Sau , yn 24 gi.

Chun : Cn chnh xc khong 0,35 g cht chun gc kali hydrophtalat, ho tan trong 50 ml acid acetic khan (TT) trong mt bnh nn c nt mi, un nng nh nu cn. Thm 0,05 ml dung dch tm tinh th (TT) v chun bng dung dch acid percloric iu ch cho n khi chuyn mu t tm sang xanh l.

Song song tin hnh mt mu trng.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,02042 g/ml.

Ghi nhit khi tin hnh chun ho. Nu nhit khi nh lng khc vi nhit lc chun ho dung dch, th tch dung dch chun acid percloric dng trong nh lng c hiu chnh theo cng thc sau:

VC = V[1 + 0,0011(t1 - t2)]

Trong :

t1 : Nhit khi chun ho.

t2 : Nhit khi nh lng.

V : Th tch dng khi nh lng.

VC : Th tch hiu chnh.

Cc dung dch acid percloric nng long hn c iu ch bng cch pha long dung dch acid percloric 0,1 N (C) vi acid acetic khan (TT).

Dung dch acid sulfuric 1 N

1 ml dung dch cha 0,04904 g acid sulfuric (H2SO4).

iu ch: Rt cn thn 30 ml acid sulfuric (TT) vo 200 ml nc, lc u, lm ngui n nhit phng v pha long vi nc va 1000 ml, trn u.

Chun : Tin hnh nh m t trong Dung dch acid hydrocloric 1 N.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,053 g/ml.

Dung dch acid sulfuric 0,5 N

1 ml dung dch cha 0,02452 g acid sulfuric (H2SO4).

iu ch: Rt cn thn 15 ml acid sulfuric (TT) vo 200 ml nc, lc u, lm ngui n nhit phng v pha long vi nc va 1000 ml, trn u.

Chun : Tin hnh nh m t trong Dung dch acid hydrocloric 0,5 N.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,0265 g/ml.

Dung dch acid sulfuric 0,1 N

1 ml dung dch cha 0,004904 g acid sulfuric (H2SO4).

iu ch: Pha long 100,0 ml dung dch acid sulfuric 1 N (C) vi nc va 1000 ml.

Chun : Tin hnh nh m t trong Dung dch acid hydrocloric 0,1 N.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,0053 g/ml.

Dung dch amoni ceri sulfat 0,1 M (Dung dch amoni v ceri sulfat 0,1 M)

1 ml dung dch cha 0,06326 g amoni ceri sulfat (2(NH4)2SO4. Ce(SO4)2. 2H2O).

iu ch: Ho tan 65,0 g amoni ceri sulfat (TT) trong hn hp 30 ml acid sulfuric (TT) v 500 ml nc, ngui v thm nc va 1000 ml.

Chun : Ly 25,0 ml dung dch amoni ceri sulfat iu ch, thm 2 g kali iodid (TT) v 150 ml nc. Chun ngay lp tc bng bng dung dch natri thiosulfat 0,1 N (C), dng dung dch h tinh bt (TT) lm ch th.

H s hiu chnh c tnh theo cng thc (2).

Bo qun trong l thu tinh nu, trnh nh sng.

Dung dch amoni sulfocyanid 0,1 N (Dung dch amoni thiocyanat 0,1 N)

1 ml dung dch cha 0,007612 g amoni sulfocyanid (NH4SCN).

iu ch: Ho tan 7,63 g amoni sulfocyanid (TT) trong nc va 1000 ml.

Chun : Ly 20,0 ml dung dch bc nitrat 0,1 N (C), thm 25 ml nc, 2 ml acid nitric 2 M (TT), 2 ml dung dch st (III) amoni sulfat (TT) v chun bng dung dch amoni sulfocyanid iu ch cho n mu hng cam.

H s hiu chnh c tnh theo cng thc (2).

Dung dch bc nitrat 0,1 N

1 ml dung dch cha 0,01699 g bc nitrat (AgNO3).

iu ch: Ho tan 17,5 g bc nitrat (TT) trong nc v pha long va 1000 ml.

Chun : Cn chnh xc khong 0,12 g cht chun gc natri clorid, ho tan trong 50 ml nc, thm vi git dung dch kali cromat (TT). Chun bng dung dch bc nitrat iu ch n khi xut hin ta mu nht.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,005844 g/ml.

Bo qun trong l thu tinh nu, trnh nh sng.

Dung dch bari clorid 0,1 M

1 ml dung dch cha 0,02443 g bari clorid (BaCl2.2H2O)

iu ch: Ho tan 24,4 g bari clorid (TT) trong nc va 1000 ml.

Chun : Ly 10,0 ml dung dch bari clorid iu ch, thm 60 ml nc, 3 ml dung dch amoniac 13,5 M (TT) v 0,5 - 1,0 mg ta phtalein (TT). Chun bng dung dch Trilon B 0,1 M (C). Khi dung dch bt u nht mu, thm 50 ml ethanol 96% (TT) v chun cho n khi mt mu tm xanh.

H s hiu chnh c tnh theo cng thc (2).

Dung dch brom 0,1 N

1 ml dung dch cha 0,00799 g brom (Br2).

iu ch: Ho tan 2,7835 g cht chun gc kali bromat v 13 g kali bromid (TT) trong nc va 1000 ml.

Bo qun dung dch trong l thu tinh nu, trnh nh sng.

Dung dch ceri sulfat 0,1 M

1 ml dung dch cha 0,04043 g ceri sulfat (Ce(SO4)2. 4H2O).

iu ch: Ho tan 40,4 g ceri sulfat (TT) trong hn hp gm 50 ml acid sulfuric (TT) v 500 ml nc, ngui v thm nc n va 1000 ml.

Chun : Tin hnh nh m t trong Dung dch amoni ceri sulfat 0,1 M, dng 25,0 ml dung dch ceri sulfat iu ch.

H s hiu chnh c tnh theo cng thc (2).

Bo qun trong l thu tinh nu, trnh nh sng.

Dung dch ch nitrat 0,1 M

1 ml dung dch cha 0,03312 g ch nitrat [Pb (NO3)2].

iu ch: Ho tan 33,0 g ch nitrat (TT) trong nc va 1000 ml.

Chun : Ly 20,0 ml dung dch ch nitrat iu ch, thm 300 ml nc v chun bng phng php chun complexon cho ch (Ph lc 10.5).

H s hiu chnh c tnh theo cng thc (2).

Dung dch ch nitrat 0,1 N (Dung dch ch nitrat 0,05 M)

1 ml dung dch cha 0,01656 g ch nitrat [Pb (NO3)2].

iu ch: Ho tan 16,6 g ch nitrat (TT) trong nc va 1000 ml.

Chun : Ly 50,0 ml dung dch ch nitrat iu ch, thm 300 ml nc v chun bng phng php chun complexon cho ch (Ph lc 10.5).

H s hiu chnh c tnh theo cng thc (2).

Dung dch iod 0,1 N

1 ml dung dch cha 0,01269 g iod (I2).

iu ch: Ho tan 20 g kali iodid (TT) trong 50 ml nc, thm 12,7 g iod (TT), lc cho tan v thm nc va 1000 ml.

Chun : Ly 25,0 ml dung dch iod iu ch, thm 1 ml dung dch acid acetic 2 M (TT) v 30 ml nc. Chun ngay lp tc bng dung dch natri thiosulfat 0,1 N (C), dng dung dch h tinh bt (TT) lm ch th.

H s hiu chnh c tnh theo cng thc (2).

Bo qun trong l thu tinh nu, trnh nh sng.

Dung dch kali bromat 0,1 N (Dung dch kali bromat 0,0167 M)

1 ml dung dch cha 0,002784 g kali bromat (KBrO3).

iu ch: Ho tan 2,7840 g cht chun gc kali bromat trong nc va 1000 ml.

Dung dch kali dicromat 0,1 N (Dung dch kali dicromat 0,0167 M)

1 ml dung dch cha 0,004903 g kali dicromat (K2Cr2O7).

iu ch: Ho tan 4,9033 g cht chun gc kali dicromat trong nc va 1000 ml.

Dung dch kali hydrophtalat 0,1 M

1 ml dung dch cha 0,02042 g kali hydrophtalat (C8H5O4K).

iu ch: Ho tan 20,42 g cht chun gc kali hydrophtalat trong khong 800 ml anhydrid acetic khan (TT), un trn cch thu cho ti khi tan hon ton, trnh m. Lm lnh ti 20 0C, thm anhydrid acetic khan (TT) va 1000 ml.

Dung dch kali hydroxyd 1 N

1 ml dung dch cha 0,05611 g kali hydroxyd (KOH).

iu ch: Ho tan 60 g kali hydroxyd (TT) trong nc khng c carbon dioxyd (TT) va 1000 ml.

Chun : Ly 25,0 ml dung dch acid hydrocloric 1 N (C) v chun bng dung dch kali hydroxyd iu ch, dng 0,5 ml dung dch phenolphtalein (TT) lm ch th.

H s hiu chnh c tnh theo cng thc (2).

Dung dch kali hydroxyd 0,1 N

1 ml dung dch cha 0,00561 g kali hydroxyd (KOH).

iu ch: Ho tan 6 g kali hydroxyd (TT) trong nc khng c carbon dioxyd (TT) va 1000 ml.

Chun : Tin hnh nh m t trong Dung dch kali hydroxyd 1 N, dng 25,0 ml dung dch acid hydrocloric 0,1 N (C).

H s hiu chnh c tnh theo cng thc (2).

Dung dch kali hydroxyd 0,5 N trong ethanol

1 ml dung dch cha 0,02805 g kali hydroxyd (KOH).

iu ch: Ho tan 30 g kali hydroxyd (TT) trong 50 ml nc v thm ethanol 96% khng c aldehyd (TT) va 1000 ml. yn 24 gi v gn nhanh phn dung dch trong sang l thu tinh mu.

Chun : Tin hnh nh m t trong Dung dch kali hydroxyd 1 N, dng 25,0 ml dung dch acid hydrocloric 0,5 N (C).

H s hiu chnh c tnh theo cng thc (2).

Bo qun trong l thu tinh nu, trnh nh sng.

Dung dch kali hydroxyd 0,1 N trong ethanol

1 ml dung dch cha 0,00561 g kali hydroxyd (KOH).

iu ch: Ho tan 6 g kali hydroxyd (TT) trong 50 ml nc v thm ethanol 96% khng c aldehyd (TT) va 1000 ml.

Chun : Tin hnh nh m t trong Dung dch kali hydroxyd 0,1 N.

H s hiu chnh c tnh theo cng thc (2).

Bo qun trong l thu tinh nu, trnh nh sng.

Dung dch kali iodat 0,05 M

1 ml dung dch cha 0,0107 g kali iodat (KIO3).

iu ch: Ho tan 10,700 g cht chun gc kali iodat trong nc va 1000 ml.

Dung dch kali iodat 0,1 N (Dung dch kali iodat 1/60 M)

1 ml dung dch cha 0,003567 g kali iodat (KIO3).

iu ch: Ho tan 3,5670 g cht chun gc kali iodat trong nc va 1000 ml.

Dung dch kali permanganat 0,1 N (Dung dch kali permanganat 0,02 M)

1 ml dung dch cha 0,00316 g kali permanganat (KMnO4).

iu ch: Ho tan 3,20 g kali permanganat (TT) trong 1000 ml nc, un nng trn cch thu 1 gi, ngui v lc qua phu thu tinh xp.

Chun : Ly 20,0 ml dung dch kali permanganat iu ch, thm 2 g kali iodid (TT) v 10 ml dung dch acid sulfuric long (TT). Chun bng dung dch natri thiosulfat 0,1 N (C), dng 1 ml dung dch h tinh bt (TT) lm ch th. Song song tin hnh mt mu trng.

H s hiu chnh tnh theo cng thc (2).

Bo qun trong l thy tinh nu, trnh nh sng.

Dung dch km clorid 0,05 M

1 ml dung dch cha 0,006815 g km clorid (ZnCl2).

iu ch: Ho tan 6,82 g km clorid (TT) trong nc. Nu cn, thm tng git dung dch acid hydrocloric 2 M (TT) cho n khi ht c v thm nc va 1000 ml.

Chun : Ly 20,0 ml dung dch km clorid iu ch, thm 5 ml dung dch acid acetic 2 M (TT) v chun bng phng php chun complexon cho km (Ph lc 10.5).

H s hiu chnh tnh theo cng thc (2).

Dung dch km sulfat 0,1 M

1 ml dung dch cha 0,02875 g km sulfat (ZnSO4.7H2O).

iu ch: Ho tan 29,0 g km sulfat (TT) trong nc va 1000 ml.

Chun : Ly 20,0 ml dung dch km sulfat iu ch, thm 5 ml dung dch acid acetic 2 M (TT) v chun bng phng php chun complexon cho km (Ph lc 10.5).

H s hiu chnh tnh theo cng thc (2).

Dung dch lithi methoxyd 0,1 M

1 ml dung dch cha 0,003797 g lithi methoxyd (CH3OLi).

iu ch: Ho tan tng lng nh 0,694 g lithi (TT) trong 150 ml methanol khan (TT), thm toluen (TT) va 1000 ml.

Xc nh chun ngay trc khi dng theo cch sau: Ly 10 ml

dimethylformamid (TT), thm 0,05 ml dung dch xanh thymol trong methanol (TT) v chun bng dung dch lithi methoxyd iu ch ti mu xanh lam. Ngay lp tc thm 0,2 g cht chun gc acid benzoic, lc cho tan hon ton v chun bng dung dch lithi methoxyd iu ch cho ti khi mu xanh lam xut hin tr li. Trnh carbon dioxyd t mi trng xung quanh trong sut qu trnh chun . S ml dung dch lithi methoxyd iu ch dng cho ln chun sau l th tch dung dch chun dng (V).

H s hiu chnh tnh theo cng thc (1), trong T = 0,01221 g/ml.

Nn bo qun trong l c gn buret t ng v thit b chng m, carbon dioxyd.

Dung dch magnesi clorid 0,1 M

1 ml dung dch cha 0,02033 g magnesi clorid (MgCl2.6H2O)

iu ch: Ho tan 20,33 g magnesi clorid (TT) trong nc va 1000 ml.

Chun : Ly chnh xc 25,0 ml dung dch magnesi clorid iu ch v chun bng phng php chun complexon cho magnesi (Ph lc 10.5).

H s hiu chnh tnh theo cng thc (2).

Dung dch magnesi sulfat 0,05 M

1 ml dung dch cha 0,01233 g magnesi sulfat (MgSO4.7H2O).

iu ch: Ho tan 12,5 g magnesi sulfat (TT) trong nc va 1000 ml.

Chun : Ly ng 25,0 ml dung dch magnesi sulfat iu ch v chun bng phng php complexon cho magnesi (Ph lc 10.5).

H s hiu chnh tnh theo cng thc (2).

Dung dch natri arsenit 0,1 M

1 ml dung dch cha 0,01299 g natri arsenit (NaAsO2).

iu ch: Ho tan 4,946 g cht chun gc arsen trioxyd trong hn hp gm 20 ml dung dch natri hydroxyd 10 M (TT) v 20 ml nc, pha long vi nc thnh 400 ml v thm dung dch acid hydrocloric 2 M (TT) cho n khi trung tnh vi giy qu. Ho tan 2 g natri hydrocarbonat (TT) trong dung dch thu c v thm nc va 500 ml.

Dung dch natri hydroxyd 1 N

1 ml dung dch cha 0,0400 g natri hydroxyd (NaOH).

iu ch: Ho tan 45,0 g natri hydroxyd (TT) trong 50 ml nc. y kn bnh bng nt cao su, yn qua m, gn phn dung dch trong trn v pha long vi nc khng c carbon dioxyd (TT) va 1000 ml.

Chun : Ly 20,0 ml dung dch natri hydroxyd iu ch, thm loi ch th s dng trong php nh lng m dung dch natri hydroxyd 1 N c s dng lm dung dch chun v chun bng dung dch acid hydrocloric 1 N (C).

H s hiu chnh tnh theo cng thc (2).

Dung dch natri hydroxyd 0,5 N

1 ml dung dch cha 0,0200 g natri hydroxyd (NaOH).

iu ch: Ho tan 25 g natri hydroxyd (TT) trong 25 ml nc v tin hnh nh m t trong Dung dch natri hydroxyd 1 N.

Chun : Tin hnh nh m t trong Dung dch natri hydroxyd 1 N, chun bng dung dch acid hydrocloric 0,5 N (C).

H s hiu chnh tnh theo cng thc (2).

Dung dch natri hydroxyd 0,1 N

1 ml dung dch cha 0,0040 g natri hydroxyd (NaOH).

iu ch: Ho tan 4,50 g natri hydroxyd (TT) trong 5 ml nc v tin hnh nh m t trong Dung dch natri hydroxyd 1 N.

Chun : Tin hnh nh m t trong Dung dch natri hydroxyd 1 N, chun bng dung dch acid hydrocloric 0,1 N (C).

H s hiu chnh tnh theo cng thc (2).

 

Dung dch natri hydroxyd 0,1N trong ethanol

1 ml dung dch cha 0,0040 g natri hydroxyd (NaOH)

iu ch: Thm 3,3 g dung dch natri hydroxyd 10 M (TT) vo 250 ml ethanol (TT).

Chun : Ho tan 0,2 g cht chun gc acid benzoic trong hn hp gm 10 ml ethanol 96% (TT) v 2 ml nc. Chun bng dung dch natri hydroxyd trong ethanol iu ch, dng 0,2 ml dung dch thymolphtalein (TT) lm ch th.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,01221 g/ml.

Dung dch natri methoxyd 0,1 M

1 ml dung dch cha 0,005402 g natri methoxyd (CH3ONa).

iu ch: Ly 175 ml methanol khan (TT), lm lnh trong nc v thm tng lng nh 2,5 g natri (TT) mi ct. Khi natri tan ht, thm toluen (TT) va n vch, lc u.

Xc nh chun ngay trc khi dng: Tin hnh nh m t trong Dung dch lithi methoxyd 0,1 N, chun bng dung dch natri methoxyd iu ch.

H s hiu chnh tnh theo cng thc (1), trong T = 0,01221 g/ml.

Nn bo qun trong l c gn buret t ng v thit b chng m, carbon dioxyd.

Dung dch natri nitrit 0,1 M

1 ml dung dch cha 0,0069 g natri nitrit (NaNO2).

iu ch: Ho tan 7,30 g natri nitrit (TT) trong nc va 1000 ml.

Xc nh chun ngay trc khi dng theo cch sau: Ho tan 0,3 g cht chun gc acid sulfanilic trong 50 ml dung dch acid hydrocloric 2 M (TT), thm 3 g kali bromid (TT), lm lnh trong nc v chun bng dung dch natri nitrit iu ch, xc nh im tng ng bng phng php chun o ampe (Ph lc 10.1).

H s hiu chnh c tnh theo cng thc (1), trong T = 0,01732 g/ml.

Bo qun trong l thu tinh nu, trnh nh sng.

Dung dch natri periodat 0,1 M

1 ml dung dch cha 0,02139 g natri periodat (NaIO4).

iu ch: Ho tan 21,4 g natri periodat (TT) trong khong 500 ml nc v thm nc va 1000 ml.

Chun : Ly 20,0 ml dung dch natri periodat iu ch cho vo bnh nn nt mi, thm 5 ml acid percloric (TT), y np bnh, lc. iu chnh ti pH 6,4 bng dung dch bo ho natri hydrocarbonat (TT), thm 10 ml dung dch kali iodid (TT), y np bnh, lc v yn 2 pht. Chun bng dung dch natri arsenit 0,1 M (C) cho n mu vng nht, thm 2 ml dung dch h tinh bt (TT) v chun chm cho ti mt mu hon ton.

H s hiu chnh tnh theo cng thc (2).

Dung dch natri thiosulfat 0,1 N

1 ml dung dch cha 0,02482 g natri thiosulfat (Na2S2O3.5H2O).

iu ch: Ho tan 25,0 g natri thiosulfat (TT) v 0,2 g natri carbonat (TT) trong nc khng c carbon dioxyd (TT) va 1000 ml.

Chun : Ly 20,0 ml dung dch kali bromat 0,1 N (C), thm 40 ml nc, 10 ml dung dch kali iodid (TT) v 5 ml dung dch acid hydrocloric 7 M (TT). Chun bng dung dch natri thiosulfat iu ch, dng 1 ml dung dch h tinh bt (TT) lm ch th.

H s hiu chnh tnh theo cng thc (2).

Dung dch tetrabutylamoni hydroxyd 0,1 M

1 ml dung dch cha 0,02595 g tetrabutylamoni hydroxyd (C16H37NO).

iu ch: Ho tan 40,0 g tetrabutylamoni iodid (TT) trong 90 ml methanol khan (TT), thm 20 g bc oxyd (TT) nghin mn v lc mnh trong 1 gi. Ly tm vi ml hn hp v th phn ng iodid ca dung dch trong trn. Nu phn ng dng tnh, thm 2 g bc oxyd (TT) v lc 30 pht. Lp li qui trnh ny cho n khi hn hp khng cn iodid. Lc hn hp qua phu lc thu tinh xp, ra bnh v phu lc 3 ln, mi ln vi 50 ml toluen (TT). Thm dch ra vo dch lc v thm toluen (TT) va 1000 ml. Cho lung kh nitrogen khng c carbon dioxyd sc 5 pht qua dung dch.

Xc nh chun ngay trc khi dng: Tin hnh nh m t trong Dung dch lithi methoxyd 0,1 N, chun bng dung dch tetrabutylamoni hydroxyd iu ch.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,01221 g/ml.

Nn bo qun trong l c gn buret t ng v thit b chng m, carbon dioxyd.

Dung dch thu ngn (II) nitrat 0,02 M

1 ml dung dch cha 0,006852 g thu ngn (II) nitrat (Hg(NO3)2.H2O).

iu ch: Ho tan 6,85 g thu ngn (II) nitrat (TT) trong 20 ml dung dch acid nitric 1 M (TT) v thm nc va 1000 ml.

Chun : Cn chnh xc khong 0,15 g cht chun gc natri clorid cho vo bnh nh mc 100 ml, thm 50 ml nc, lc cho tan hon ton v thm nc va 100 ml, lc u. Ly 10,0 ml dung dch thu c, thm 40 ml nc. Chun bng dung dch thu ngn nitrat iu ch, xc nh im tng ng bng phng php chun o in th (Ph lc 10.2), dng in cc ch th platin hoc thu ngn v in cc so snh thu ngn - thu ngn (I) sulfat.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,002338 g/ml.

Dung dch Trilon B 0,05 M (Dung dch natri edetat 0,05 M)

1 ml dung dch cha 0,01861 g Trilon B (C10H14N2O8Na2. 2H2O).

iu ch: Ho tan 18,8 g Trilon B (TT) trong nc va 1000 ml.

Chun : Cn chnh xc khong 1,64 g cht chun gc km ht, ho tan trong 20 ml dung dch acid sulfuric long (TT), thm nc va 500 ml. Ly 25,0 ml dung dch thu c, thm 5 ml dung dch m amoniac pH 10,0 (TT), khong 0,1 g hn hp ch th en eriocrom T (TT) v 70 ml nc. Chun bng dung dch Trilon B iu ch cho n khi chuyn mu sang xanh lam.

H s hiu chnh c tnh theo cng thc (1) trong T = 0,003269 g/ml.

Dung dch Trilon B 0,1 M (Dung dch natri edetat 0,1M)

1 ml dung dch cha 0,03722 g Trilon B (C10H14N2O8Na2. 2H2O).

iu ch: Ho tan 37,5 g Trilon B (TT) trong nc va 1000 ml.

Chun : Tin hnh nh m t trong Dung dch Trilon B 0,05 M.

H s hiu chnh c tnh theo cng thc (1), trong T = 0,00654 g/ml.