scholarly journals Mathematical Interpretation of Initial Curve of Acid-Base Titration between Strong Base and Weak Acid: Taking NaOH and HAc as an Example

Daxue Huaxue ◽  
2020 ◽  
Vol 0 (0) ◽  
pp. 3-0
Author(s):  
Shuzhe Sun ◽  
Zehao Zhang ◽  
Bin Zhang
Keyword(s):  
Weak Acid ◽  
Initial Curve ◽  
Acid Base ◽  
Strong Base ◽  
Acid Base Titration ◽  
Mathematical Interpretation

ETHANOLIC EXTRACT OF ARISTOLOCHIA BRACTEOLATA FLOWER AS A NATURAL INDICATOR FOR ACID-BASE TITRATION

INDIAN DRUGS ◽  
2019 ◽  
Vol 56 (03) ◽  
pp. 77-79
Author(s):  
G Vambhurkar ◽  
A. Jagtap ◽  
A. Gavade ◽  
M Kengar ◽  
M Bhutkar ◽  
...  
Keyword(s):  
Ethanolic Extract ◽  
Strong Acid ◽  
Weak Acid ◽  
Weak Base ◽  
Acid Base ◽  
Ph Indicator ◽  
Strong Base ◽  
Color Changes ◽  
Synthetic Indicators ◽  
Acid Base Titration

In acid-base titration or acid-base neutralization reaction the change in color due to change pH of the solution is caused due to a third substance which is termed as acid-base indicator or pH indicator. Every indicator shows different range of colors at different pH ranges. Synthetic indicators have been widely employed as indicators in acid-base titrations; however, due to environmental pollution, availability and cost, natural compounds are best alternates. Natural pigments in plants are highly colored substances and may show sharp color changes with variation in pH. In the present study an attempt has been made to extract natural indicator from flower of Aristolochia bracteolate. The equivalence points of the titrations namely strong acid-strong base, strong acid-weak base, weak acid-strong base and weak acid weak base titrations, using flower extract of A. bracteolate were coincident with the equivalence points obtained by the synthetic indicator phenolpthalein. From the results of the study, it may be concluded that ethanolic extract of A. bracteolate flower as an indicator for acid-base titration could be effectively employed as a substitute to the synthetic acid-base indicators.

scholarly journals GREEN CHEMISTRY: ROSELLE’S COROLLA EXTRACT AS A SUBSTITUTE FOR HAZARDOUS INTERNAL INDICATORS IN VOLUMETRIC ANALYSIS

2019 ◽  
Vol 7 (9) ◽  
pp. 118-122
Author(s):  
R. F. Pagariya
Keyword(s):  
Strong Acid ◽  
Weak Acid ◽  
Basic Solution ◽  
Phenol Red ◽  
Weak Base ◽  
Acid Base ◽  
Ph Indicator ◽  
Strong Base ◽  
Synthetic Indicators ◽  
Acid Base Titration

Indicators used in acid-base titration show well marked changes of colour in certain intervals of pH. Most of these indicators are organic dyes and are of synthetic origin. Today synthetic indicators are the choice of neutralization titrations. But due to environmental pollution, availability and cost, the search for natural compounds as an acid-base indicator was started. The present work highlights the use of the ethanolic extract of the corolla of Roselle (Hibiscus sabdariffa) as a pH indicator in strong acid-strong base, strong acid weak base, weak acid strong base and weak acid-weak base titrations. This natural indicator is easy to extract as well as easily available. The results showed that the Roselle’s corolla indicator gave red color in acidic solution, while green in basic solution. The comparison indicators used in this research were phenolphthalein, methyl red and phenol red. Hopeful results were obtained when it was compared against standard synthetic indicators. The equivalence points obtained match with the equivalence points obtained by standard indicators. Therefore this natural indicator is found to be useful, economical, simple, precise and eco-friendly for acid base titration.

scholarly journals Flower Extracts of Cage Plants (Canavalia virosa) as an Indicator of Acid Base

2020 ◽  
Vol 9 (4) ◽  
pp. 191-198
Author(s):  
Andi M. Rendi ◽  
Supriadi Supriadi ◽  
Suherman Suherman
Keyword(s):  
Strong Acid ◽  
Weak Acid ◽  
Acid Base ◽  
Buffer Solution ◽  
Strong Base ◽  
Flower Extract ◽  
Acid Titration ◽  
Acid Base Titration ◽  
Plant Flower ◽  
Light Green

Cage plants (Canavalia virosa) are classified as nuts. This study aims to prove the flowers of the cage plants as acid-base indicators and determine the type of acid-base titration that is suitable for indicators of cage plants. The flowers of the cage plants were macerated with ethanol. Extras were tested as indicators in acid-base solutions, buffer solutions, and compared with phenolphthalein and methyl orange for acid-base titration, namely: strong acid with a strong base, a weak acid with a strong base, and weak base with strong acid. The results obtained in this study, namely: flower extracts of cage plants in strong red acid, in weak acid pink, in strong green bases, and weak bases in light green. In a buffer solution of pH 1 to pH 11, the flower extract of the cage plants gives 4 color groups, namely: a buffer solution with pH 1 colored red, pH 3 colored pink, pH 5 to pH 9 being light green, and pH 11 being dark blue. Cage plant flower extract can be used as an indicator of acid-base, cage plant flower extract can be used on strong-base strong acid titration, strong weak-acid base, and weak-strong base acid titration.

Henderson Hasselbalch Relationship and Weak Acid Titration

2019 ◽  
Author(s):  
Marc Blétry
Keyword(s):  
Theoretical Framework ◽  
Weak Acid ◽  
Acid Base ◽  
Sensitive Technique ◽  
Chemistry Students ◽  
Advanced Students ◽  
Acid Titration ◽  
Acid Base Titration ◽  
Analytical Expressions

Henderson-Hasselbalch relation is generally the simplified theoretical framework used to introduce students to acid-base titration. However, it is not always valid and its limitations should be made clear to chemistry students. The appropriate parameter to evaluate its validity is K a /C 0 , in connection with Ostwald dilution law. For more advanced students, it is possible to deduce analytical expressions that always fit accurately acid-base titrations and allow an evaluation of Henderson Hasselbalch relation. Gran plot appears as a particularly sensitive technique to the breakdown of Henderson Hasselbalch relation.

scholarly journals Utilization of Extract of Sambang Getih Leaves (Hemigraphis colorata. Hall. F) as a Acid-Base Indicator

2020 ◽  
Vol 9 (1) ◽  
pp. 7-15
Author(s):  
Eksari Ekasari ◽  
Purnama Ningsih
Keyword(s):  
Leaf Extract ◽  
Strong Acid ◽  
Weak Base ◽  
Acid Base ◽  
Strong Base ◽  
Unique Color ◽  
Acid Base Titration ◽  
Naoh Solution ◽  
Ph Range ◽  
Color Pigment

Getih sambang leaves (Hemigraphis Colorata. Hall. F) are plants that have a distinctive and unique color, namely the upper surface of the leaf is green and the bottom of the leaf is burgundy where sambang leaves contain anthocyanin compounds. Anthocyanin is the color pigment in plants that forms the basis of the use of natural indicators. This study aims to prove whether getih cucumber leaves can be used as an acid-base indicator, to determine the type of acid-base titration that is suitable for indicators of getih cucumber leaves, and to find out what the pH-changing color route of getih cucumber leaves is. The method used is extraction, namely maceration. Wee leaves are macerated by using methanol as a solvent for 24 hours. The extract was previously tested using HCl solution and NaOH solution as a test to prove the presence of anthocyanin. The results obtained in this study, getih sambang leaf extract can be used as an indicator of acid base, and also the type of acid-base titration that is suitable for use in the indicator of getih leaf extract extract precisely on the titration of strong-base strong acid, and strong weak base-acid It is best used as a substitute for the phenolphthalein indicator. In titration of strong and weak acids and bases, it is good to be used as a substitute for the indicator of methyl orange. The pH range obtained from the getih sambang leaf extract is pH 4-7 (red-purple).

Equivalence Points and Inflexion Points in Acid-Base Titration Curves

1963 ◽  
Vol 16 (5) ◽  
pp. 759 ◽  
Author(s):  
RH Stokes
Keyword(s):  
Strong Acid ◽  
Ionization Constants ◽  
Weak Acids ◽  
Acid Base ◽  
Strong Base ◽  
Titration Curves ◽  
Acid Base Titration

General equations are derived for the relation between pH and stoichiometric degree of neutralization in the titration of monoprotic and diprotic weak acids (or bases) with strong acid or strong base. From these equations the number and position of inflexion points in the curves is derived, and their relation to the equivalence points is shown. Methods for determining ionization constants from inflexion points are discussed.

The Acid–Base Titration of a Very Weak Acid: Boric Acid

2012 ◽  
Vol 89 (6) ◽  
pp. 767-770 ◽  
Author(s):  
M. Celeste C. Azevedo ◽  
Ana M. V. Cavaleiro
Keyword(s):  
Boric Acid ◽  
Weak Acid ◽  
Acid Base ◽  
Acid Base Titration

scholarly journals Indikator Asam-Basa dari Bunga Dadap Merah (Erythrina crista-galliL.)

2017 ◽  
Vol 5 (1) ◽  
pp. 29
Author(s):  
Rahmawati Rahmawati ◽  
Siti Nuryanti ◽  
Ratman Ratman
Keyword(s):  
Colour Change ◽  
Strong Acid ◽  
Weak Acid ◽  
Weak Base ◽  
Acid Base ◽  
Buffer Solution ◽  
Strong Base ◽  
Flower Extract ◽  
Red Color ◽  
Dark Green

Dadap red (erythrina crista-galli L.) is belonged to the legumes (fabaceaea) family which, is one of the flowering shade plants that often used as an ornamental plant. This plant has a bright red flower, a taproot with root nodule bacteria nitrogen fixation and compound leaf consists three strands on each stem. This research is climed to proves that the extract of dadap red flower can be used as acid-base indicators. Dadap red flowers was macerated using methanol then filtered. The filtrate was ready to use as an acid-base indicator. The extract is tested in an acid-base, buffer solutions, and was compared with phenolphthalein for a strong acid with a strong base while a methyl orange a weak base with a strong acid. Based on the result, indicator of dadap red flower extrat in the strong acid was red colour, while in the weak acid was pink, and also in the strong base was dark green and in the weak base was purple. Furthermore, in the buffer solution, the indicator of dadap red flower extract gave four groups of colour change, namely red color at pH 1 to pH 6, colorless at pH 7 to pH 9, brown at pH 10 and blue at pH 11 to pH 12. Additionally, to attain the end point of titration, the indicators of dadap red flower extract gives a similar results with the comparison indicators. The results showed that the indicator of dadap red flower extracts can be used as an alternative indicator.

Henderson Hasselbalch Relationship and Weak Acid Titration

2019 ◽  
Author(s):  
Marc Blétry
Keyword(s):  
Theoretical Framework ◽  
Weak Acid ◽  
Acid Base ◽  
Sensitive Technique ◽  
Chemistry Students ◽  
Advanced Students ◽  
Acid Titration ◽  
Acid Base Titration ◽  
Analytical Expressions

Henderson-Hasselbalch relation is generally the simplified theoretical framework used to introduce students to acid-base titration. However, it is not always valid and its limitations should be made clear to chemistry students. The appropriate parameter to evaluate its validity is K a /C 0 , in connection with Ostwald dilution law. For more advanced students, it is possible to deduce analytical expressions that always fit accurately acid-base titrations and allow an evaluation of Henderson Hasselbalch relation. Gran plot appears as a particularly sensitive technique to the breakdown of Henderson Hasselbalch relation.

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