Acid-Base Indicators
- Page ID
- 11840
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)
( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\id}{\mathrm{id}}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\kernel}{\mathrm{null}\,}\)
\( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\)
\( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\)
\( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)
\( \newcommand{\vectorA}[1]{\vec{#1}} % arrow\)
\( \newcommand{\vectorAt}[1]{\vec{\text{#1}}} % arrow\)
\( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vectorC}[1]{\textbf{#1}} \)
\( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)
\( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)
\( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)The quantities listed in the "Preparation" column ought to be considered to be only good approximations. The audience of users, the decision whether to determine a titration error for a particular color change and the experimental environment must be considered when deciding what quantity is best to use.
| Indicator | pH Change | Color Change | Preparation |
|---|---|---|---|
| Methyl Violet | 0.0 - 1.6 | yel to bl | 0.01- 0.05 % in water |
| Crystal Violet | 0.0 - 1.8 | yel to bl | 0.02% in water |
| Ethyl Violet | 0.0 - 2.4 | yel to bl | 0.1 g in 50 ml of MeOH + 50 ml of water |
| Malachite Green | 0.2 - 1.8 | yel to bl grn | water |
| Methyl Green | 0.2 - 1.8 | yel to bl | 0.1% in water |
| 2 - (p - dimethylaminophenylazo)pyridine | 0.2 - 1.8, 4.4 - 5.6 | yel to bl, red to yel | 0.1 % in ETOH |
| o - Cresolsulfonephthalein (Cresol Red) | 0.4 - 1.8, 7.0 - 8.8 | yel to red, yel to red | 0.1 g in 26.2 ml 0.01M NaOH + 223.8 ml water |
| Quinaldine Red | 1.0 - 2.2 | col to red | 1 % in ETOH |
| p - (p - dimethylaminophenylazo) - benzoic acid, Na - salt (Paramethyl Red) | 1.0 - 3.0 | red to yel | ETOH |
| m - (p - anilnophenylazo)benzene sulfonic acid, Na - salt (Metanil Yellow) | 1.2 - 2.4 | red to yel | 0.01% in water |
| 4 - Phenylazodiphenylamine | 1.2 - 2.6 | red to yel | 0.01 g in 1 ml 1M HCI + 50 ml ETOH + 49 ml water |
| Thymolsulfonephthalein (Thymol Blue) | 1.2 - 2.8, 8.0 - 9.6 | red to yel, yel to bl | 0.1 g in 21.5 ml 0.01 M NaOH + 229.5 mL water |
| m - Cresolsulfonephthalein (Metacresol Purple) | 1.2 - 2.8, 7.4 - 9.0 | red to yel, yel to purp | 0.1 g in 26.2 ml 0.01M NaOH + 223.8 ml water |
| p - (p - anilinophenylazo)benzenesulfonic acid, Na - salt (Orange IV) | 1.4 - 2.8 | red to yel | 0.01 % in water |
| 4 - o - Tolylazo - o - toluidine | 1.4 - 2.8 | or to yel | water |
| Erythrosine, disodium salt | 2.2 - 3.6 | or,to red | 0.1% in water |
| Benzopurpurine 48 | 2.2 - 4.2 | vt to red | 0. 1 170 in water |
| N,N - dimethyl - p - (m - tolylazo)aniline | 2.6 - 4.8 | red to yel | 0.1% in water |
| 4,4' - Bix(2 - amino - l - naphthylazo)2,2' - stil - benedisulfonic acid | 3.0 - 4.0 | purp to red | 0.1 g in 5.9 ml 0.05 M NaOH + 94.1 ml water |
| Tetrabromophenolphthaleinethyl ester, K - salt | 3.0 - 4.2 | yel to bl | 0.1 % in ETOH |
| 3',3",5',5" - tetrabromophenol - sulfonephthalein (Bromophenol Blue) | 3.0 - 4.6 | yel to bl | 0.1 g in 14.9 ml 0.01M NaOH + 235.1 ml water |
| 2,4 - Dinitrophenol | 2.8 - 4.0 | colorless to yel | saturated water solution |
| N,N - Dimethyl - p - phenylazoaniline (p - Dimethylaminoazobenzene) | 2.8 - 4.4 | red to yel | 0.1 g in 90 ml in ETOH + 10 ml water |
| Congo Red | 3.0 - 5.0 | blue to red | 0.1% in water |
| Methyl Orange - Xylene Cyanole solution | 3.2 - 4.2 | purp to grn | ready solution |
| Methyl Orange | 3.2 - 4.4 | red to yel | 0.01 % in water |
| Ethyl Orange | 3. 4 - 4. 8' | red to yel | 0.05 - 0.2% in water or aqueous ETOH |
| 4 - (4 - Dimethylamino - 1 - naphthylazo) - 3 - methoxybenzenesulfonic acid | 3.5 - 4.8 | vt to yel | 0.1% in 60% ETOH |
| 3',3",5',5" - Tetrabromo - m - cresol - sulfonephthalein (Bromocresol Green) | 3.8 - 5.4 | yel to blue | 0.1 g in 14.3 ml 0.01 M NaOH + 235.7 ml water |
| Resazurin | 3.8 - 6.4 | or to vt | water |
| 4 - Phenylazo - l - naphthylamine | 4.0 - 5.6 | red to yel | 0.1 % in ETOH |
| Ethyl Red | 4.0 - 5.8 | col to red | 0.1 g in 50 ml MEOH + 50 ml water |
| 2 - (p - Dimethylaminophenylazo) - pyridine | 0.2 - 1.8, 4.4 - 5.6 | yel to red, red to yel | 0.1 % in ETOH |
| 4 - (p - ethoxyphenylazo) - m - phenylene - diamine monohydrochloride | 4.4 - 5.8 | or to yel | 0.1% in water |
| Lacmoid | 4.4 - 6.2 | red to bl | 0.2% in ETOH |
| Alizarin Red S | 4.6 - 6.0 | yel to red | 0.2 g in 100 mL of 1.5% HCl |
| Methyl Red | 4.8 - 6.0 | red to yel | 0.02 g in 60 ml ETOH + 40 ml water |
| Propyl Red | 4.8 - 6.6 | red to yel | ETOH |
| 5',5" - Dibromo - o - cresolsulfone - phthalein (Bromocresol Purple) | 5.2 - 6.8 | yel to purp | 0.1 g in 18.5 ml 0.01M NaOH + 231.5 ml water |
| 3',3" - Dichlorophenolsulfonephthalein (Chlorophenol Red) | 5.2 - 6.8 | yel to red | 0.1 g in 23.6 ml 0.01 M NaOH + 226.4 ml water |
| p - Nitrophenol | 5.4 - 6.6 | col to yel | 0.1% in water |
| Alizarin | 5.6 - 7.2, 11.0 - 12.4 | yel to red, red to purp | 0.1 % in MEOH |
| 2 - (2,4 - Dinitrophenylazo) - l - naphthol - 3, 6 - disulfonic acid, di - Na salt | 6.0 - 7.0 | yel to bl | 0.1% in water |
| 3',3" - Dibromothymolsulfonephthalein (Bromothymol Blue) | 6.0 - 7.6 | yel to bl | 0.1 gin 16 ml 0.01 M NaOH + 234 ml water |
| 6,8 - Dinitro - 2,4 - (lH)quinazolinedione (m - Dinitrobenzoylene urea) | 6.4 - 8.0 | col to yel | 25 g in 115 ml M NaOH + 50 ml boiling water 0.292g of NaCl in 100 ml water |
| Brilliant Yellow | 6.6 - 7.8 | yel to or | 1 % in water |
| Phenolsulfonephthalein (Phenol Red) | 6.6 - 8.0 | yel to red | 0.1 gin 28.2 ml 0.01M NaOH + 221.8 ml water |
| Neutral Red | 6.8 - 8.0 | red to amb | 0.01 g in 50 ml ETOH + 50 ml water |
| m - Nitrophenol | 6.8 - 8.6 | col to yel | 0.3170 in water |
| o - Cresolsulfonephthalein (Cresol Red) | 0.0 - 1.0, 7.0 - 8.8 | red to yel, yel to red | 0.1 g in 26.2 ml 0.01 M NaOH + 223.8 ml water |
| Curcumin | 7.4 - 8.6, 10.2 - 11.8 | yel to red | ETOH |
| m - Cresolsulfonephthalein (Metacresol Purple) | 1.2 - 2.8, 7.4 - 9.0 | red to yel, yel to purp | 0.1 gin 26.2 ml 0.01M NaOH + 223.8 ml water |
| 4,4' - Bis(4 - amino - i - Daphthylazo) 2,2'stilbene disulfonic acid | 8.0 - 9.0 | bl to red | 0.1 gin 5.9 ml 0.05 M NaOH + 94.1 ml water |
| Thymolsulfonephthalein (Thymol Blue) | 1.2 - 2.8, 8.0 - 9.6 | red to yel | 0.1 g in 21.5 ml 0.01 M NaOH + 228.5 ml water |
| o - Cresolphthalein | 8.2 - 9.8 | col to red | 0.04% in ETOH |
| p - Naphtholbenzene | 8.2 - 10.0 | or to bl | I % in dil. alkali |
| Phenolphthalein | 8.2 - 10.0 | col to pink | 0.05 gin 50 mL ETOH + 50 mL water |
| Ethyl - bis (2.4 - dimethylphenyl)acetate | 8.4 - 9.6 | col to bl | saturated solution in 50% acetone alcohol |
| Thymolphthalein | 9.4 - 10.6 | col to bl | 0.04 g in 50 ml ETOH + 50 ml water |
| 5 - (p - Nitrophenylazo)salicylic acid, Na - salt (Alizarin Yellow R) | 10.1 - 12.0 | yel to red | 0.01 % in water |
| p - (2,4 - Dihydroxyphenylazo)benzene - sulfonic acid, Na - salt | 11.4 - 12.6 | yel to or | 0.1 % in water |
| 5,5' - Indigodisulfonic acid, di - Na - salt | 11.4 - 13.0 | bl to yel | water |
| 2,4,6 - Trinitrotoluene | 11.5 - 13.0 | co] to or | 0.1 - 0.5% in ETOH |
| 1,3,5 - Trinitrobenzene | 12.0 - 14.0 | col to or | 0.1 - 0.5% in ETOH |
| Clayton Yellow | 12.2 - 13.2 | yel to amb | 0.1% in water |