nada

Indicadores ácido - base

070_NaturalIndica.mov

pH

7

8,5

9,4

9,8

12

fenolftaleína (8,3 - 10,0)

Indicador
Amarillo

Amarillo de alizarina-R

Violeta
Azul

IncoloroTimolftaleína
Fenolftaleína

Incoloro

Azul de timol
(rango básico)

Amarillo

Rojo

Amarillo

Rojo de fenol
Azul de bromotimol

Rojo

Naranja de metilo
Azul de bromofenol
Azulde timol
Rojo
(rango ácido)
Amarillo

Violeta de metilo

Azul
Rojo

Amarillo

Rojo de metilo
Verde de bromocresol

Rojo

Amarillo

Rojo de clorofenol

Amarillo

AzulAzul-violeta

Amarillo
Amarillo
Violeta

Amarillo

Amarillo-naranja

Rojo

Azul

NH4Cl

NaCl

NaAc

azul de bromotimol (6,0 – 7,6)
Hidrólisis
NaCl → Na+ + Cl2 H2O ⇔ H3O+ + HOHCl → H++ Cl-

NaOH → Na+ + HOpH = 7

NaAc → Na+ + Ac2 H2O ⇔ H3O+ + HOHAc + H2O ⇔ H3O+ + Ac-

Ka

[H O ][Ac ]
=
3

+

−

[HAc]

[HAc][HO - ]
Kh =
[Ac- ]

Ac- + H2O ⇔ HAc + HOpH > 7

2H2O ⇔

H3O+

+

K w = [H 3O + ][HO − ]

HO-

K=

Ac- + H3O+ ⇔ HAc + H2O

[HAc][HO - ] K w
Kh =
=
Ka
[Ac ]

Ac- + H2O ⇔ HAc + HO-

Kh =

[HAc]
1
=
[Ac− ][H 3O + ] K a

KwKa

NH4Cl → NH4+ + Cl2 H2O ⇔ H3O+ + HONH3 + H2O ⇔ NH4+ + HO-

[NH ][HO ]
=
+

Kb

4

−

[NH 3 ]

[NH 3 ][H 3O + ]
Kh =
[NH + ]
4

NH4+ + H2O ⇔ NH3 + H3O+
pH < 7

K w = [H 3O+ ][HO − ]

2 H2O ⇔ H3O+ + HO-

K=

NH4+ + HO- ⇔ NH3 + H2O

[NH 3 ][H 3O + ] K w
Kh =
=
+
Kb
[NH 4 ]

NH4+ + H2O ⇔ NH3 + H3O+

Kh =

[NH 3 ]
1
=
[NH + ][HO − ] K b
4

Kw
KbNH4NO2 → NH4+ + NO2NH4+ + H2O ⇔ NH3 + H3O+

b
Kh

[NH 3 ][H 3O + ] K w
=
=
+
Kb
[NH 4 ]

NO2- + H2O ⇔ HNO2 + HO-

a
Kh

[HNO 2 ][HO − ] K w
=
=
−
Ka
[NO 2 ]

Kb = 1.8 x 10-5Ka = 4.5 x 10-4
pH < 7

NH4CN → NH4+ + CNNH4+ + H2O ⇔ NH3 + H3O+
CN- + H2O ⇔ HCN + HOKb = 1.8 x 10-5

b
Kh

a
Kh

[NH 3 ][H 3O + ] K w
=
=
+
Kb
[NH 4 ]

[HCN][HO − ] K w
=...