They both are indicators used to determine endpoint (equivalence points).
However, to aid in your knowledge, choice of indicators depends on the nature of titrant and titrate i.e. strong acid vs weak base, weak acid vs strong base etc.
now come to your question phenolphthalien is ideally used in where strong base is used and it gives the light pink color which becomes darker on further addition of base. (in acidic conditions it is colourless)
On the other hand methyl orange is used when strong acid is used and it turns from orange to yellow.
They both are indicators used to determine endpoint (equivalence points).
However, to aid in your knowledge, choice of indicators depends on the nature of titrant and titrate i.e. strong acid vs weak base, weak acid vs strong base etc.
now come to your question phenolphthalien is ideally used in where strong base is used and it gives the light pink color which becomes darker on further addition of base. (in acidic conditions it is colourless)
On the other hand methyl orange is used when strong acid is used and it turns from orange to yellow.
In terms of the pH color change, phenolphthalein turns from colorless to pink at pH 8.2, while methyl orange changes at about pH 4. In a titration with standard base, the accuracy of the determination will be affected if the wrong indicator is used. For example, weak acids like acetic or tartaric should be titrated with phenolphthalein as the indicator, because at methyl orange’s endpoint at pH 4 these acids are not completely titrated yet. In a procedure to assay sodium carbonate, on the other hand, the titration is done by adding excess HCl, then titrating the remaining HCl to a methyl orange endpoint (all HCl will have been titrated at pH 4), because the CO2 released would make the endpoint unreadable at pH 8.2.
In terms of the pH color change, phenolphthalein turns from colorless to pink at pH 8.2, while methyl orange changes at about pH 4. In a titration with standard base, the accuracy of the determination will be affected if the wrong indicator is used. For example, weak acids like acetic or tartaric should be titrated with phenolphthalein as the indicator, because at methyl orange’s endpoint at pH 4 these acids are not completely titrated yet. In a procedure to assay sodium carbonate, on the other hand, the titration is done by adding excess HCl, then titrating the remaining HCl to a methyl orange endpoint (all HCl will have been titrated at pH 4), because the CO2 released would make the endpoint unreadable at pH 8.2.
Methyl orange is a better indicator for the titration of HCl with Na2CO3. It has yellow colour in the basic medium and red colour in acid medium. The CO2 evolved may change the pH of methyl red.
Methyl orange is a better indicator for the titration of HCl with Na2CO3. It has yellow colour in the basic medium and red colour in acid medium. The CO2 evolved may change the pH of methyl red.
Indicator choice is based on the pH of the equivalence point for the acid-base titration you are doing. You should choose an indicator that changes colour at or near the equivvalence point. The titration curve is steep then, and you will get a good end point.
Phenolphthalein changes colour at a pH above 7. So it is quite good as an indicator for titrations of strong acids with strong bases. It is also suitable for titrations of weak acids and strong bases, which have an equivalence point at a pH above 7.
It is not a good choice for a titration between a strong acid and a weak base, as the equivalence point is below a pH of 7. Methyl orange changes colour at a suitable pH.
Indicator choice is based on the pH of the equivalence point for the acid-base titration you are doing. You should choose an indicator that changes colour at or near the equivvalence point. The titration curve is steep then, and you will get a good end point.
Phenolphthalein changes colour at a pH above 7. So it is quite good as an indicator for titrations of strong acids with strong bases. It is also suitable for titrations of weak acids and strong bases, which have an equivalence point at a pH above 7.
It is not a good choice for a titration between a strong acid and a weak base, as the equivalence point is below a pH of 7. Methyl orange changes colour at a suitable pH.
Methyl orange is used as an indicator with acid, the color of the solution turns red. When methyl orange is used as an indicator with base, the color of the solution turns yellow.
As dilute hydrochloric is acidic in nature, when methyl orange is added to it, the color of the solution turns red.
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.
.
After adding methyl orange to HCl, your solution will kinda look like this ↓↓↓
Methyl orange is used as an indicator with acid, the color of the solution turns red. When methyl orange is used as an indicator with base, the color of the solution turns yellow.
As dilute hydrochloric is acidic in nature, when methyl orange is added to it, the color of the solution turns red.
.
.
.
After adding methyl orange to HCl, your solution will kinda look like this ↓↓↓
There are 2 theories of indicators which explain colour change .
1)Ostwald's Theory
According to this theory: (a) The colour change is due to ionisation of the acid-base indicator. The unionised form has different colour than the ionised form. (b) The ionisation of the indicator is largely affected in acids and bases as it is either a weak acid or a weak base.
In short it said that every indicator is itself a weak acid or weak base and thus colour change could be explained by the ionization equation of the indicator taking in consideration the common ion effect which is a consequence of Le Chatlier's Principle .
The Drawback of this theory : It failed to explain the structural changes .
2)The Modern Benzenoid Theory
It says that indicators exist in interconvertible forms - Benzenoid and Quinonoid . One form predominates in one medium and other in the other medium .
Quinonoid form is more deeper in colour than Benzenoid form .
In case of Methyl Orange it exists in Quinonoid form in Acidic medium , showing red colour and Benzenoid form in basic medium showing yellow colour.
There are 2 theories of indicators which explain colour change .
1)Ostwald's Theory
According to this theory: (a) The colour change is due to ionisation of the acid-base indicator. The unionised form has different colour than the ionised form. (b) The ionisation of the indicator is largely affected in acids and bases as it is either a weak acid or a weak base.
In short it said that every indicator is itself a weak acid or weak base and thus colour change could be explained by the ionization equation of the indicator taking in consideration the common ion effect which is a consequence of Le Chatlier's Principle .
The Drawback of this theory : It failed to explain the structural changes .
2)The Modern Benzenoid Theory
It says that indicators exist in interconvertible forms - Benzenoid and Quinonoid . One form predominates in one medium and other in the other medium .
Quinonoid form is more deeper in colour than Benzenoid form .
In case of Methyl Orange it exists in Quinonoid form in Acidic medium , showing red colour and Benzenoid form in basic medium showing yellow colour.
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They both are indicators used to determine endpoint (equivalence points).
However, to aid in your knowledge, choice of indicators depends on the nature of titrant and titrate i.e. strong acid vs weak base, weak acid vs strong base etc.
now come to your question phenolphthalien is ideally used in where strong base is used and it gives the light pink color which becomes darker on further addition of base. (in acidic conditions it is colourless)
On the other hand methyl orange is used when strong acid is used and it turns from orange to yellow.
for your further reading please check acid-base indicators ..
Thanks.
They both are indicators used to determine endpoint (equivalence points).
However, to aid in your knowledge, choice of indicators depends on the nature of titrant and titrate i.e. strong acid vs weak base, weak acid vs strong base etc.
now come to your question phenolphthalien is ideally used in where strong base is used and it gives the light pink color which becomes darker on further addition of base. (in acidic conditions it is colourless)
On the other hand methyl orange is used when strong acid is used and it turns from orange to yellow.
for your further reading please check acid-base indicators ..
Thanks.
More
VOTE
In terms of the pH color change, phenolphthalein turns from colorless to pink at pH 8.2, while methyl orange changes at about pH 4. In a titration with standard base, the accuracy of the determination will be affected if the wrong indicator is used. For example, weak acids like acetic or tartaric should be titrated with phenolphthalein as the indicator, because at methyl orange’s endpoint at pH 4 these acids are not completely titrated yet. In a procedure to assay sodium carbonate, on the other hand, the titration is done by adding excess HCl, then titrating the remaining HCl to a methyl orange endpoint (all HCl will have been titrated at pH 4), because the CO2 released would make the endpoint unreadable at pH 8.2.
In terms of the pH color change, phenolphthalein turns from colorless to pink at pH 8.2, while methyl orange changes at about pH 4. In a titration with standard base, the accuracy of the determination will be affected if the wrong indicator is used. For example, weak acids like acetic or tartaric should be titrated with phenolphthalein as the indicator, because at methyl orange’s endpoint at pH 4 these acids are not completely titrated yet. In a procedure to assay sodium carbonate, on the other hand, the titration is done by adding excess HCl, then titrating the remaining HCl to a methyl orange endpoint (all HCl will have been titrated at pH 4), because the CO2 released would make the endpoint unreadable at pH 8.2.
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Methyl orange is a better indicator for the titration of HCl with Na2CO3. It has yellow colour in the basic medium and red colour in acid medium. The CO2 evolved may change the pH of methyl red.
Methyl orange is a better indicator for the titration of HCl with Na2CO3. It has yellow colour in the basic medium and red colour in acid medium. The CO2 evolved may change the pH of methyl red.
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Litmus paper methyl orange and phenolphthalein are used as a pH indicator. Below are the result that we get.
In acid
Litmus Paper - Red
Methyl Orange - Red
Phenolphthalein - Colourless
In base
Litmus Paper - Blue
Methyl Orange - Yellow
Phenolphthalein - Light Pink
Neutral
Litmus Paper - No Change
Methyl Orange - Orange
Phenolphthalein - Colourless
Litmus paper methyl orange and phenolphthalein are used as a pH indicator. Below are the result that we get.
In acid
Litmus Paper - Red
Methyl Orange - Red
Phenolphthalein - Colourless
In base
Litmus Paper - Blue
Methyl Orange - Yellow
Phenolphthalein - Light Pink
Neutral
Litmus Paper - No Change
Methyl Orange - Orange
Phenolphthalein - Colourless
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VOTE
Indicator choice is based on the pH of the equivalence point for the acid-base titration you are doing. You should choose an indicator that changes colour at or near the equivvalence point. The titration curve is steep then, and you will get a good end point.
Phenolphthalein changes colour at a pH above 7. So it is quite good as an indicator for titrations of strong acids with strong bases. It is also suitable for titrations of weak acids and strong bases, which have an equivalence point at a pH above 7.
It is not a good choice for a titration between a strong acid and a weak base, as the equivalence point is below a pH of 7. Methyl orange changes colour at a suitable pH.
Indicator choice is based on the pH of the equivalence point for the acid-base titration you are doing. You should choose an indicator that changes colour at or near the equivvalence point. The titration curve is steep then, and you will get a good end point.
Phenolphthalein changes colour at a pH above 7. So it is quite good as an indicator for titrations of strong acids with strong bases. It is also suitable for titrations of weak acids and strong bases, which have an equivalence point at a pH above 7.
It is not a good choice for a titration between a strong acid and a weak base, as the equivalence point is below a pH of 7. Methyl orange changes colour at a suitable pH.
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VOTE
Methyl orange is used as an indicator with acid, the color of the solution turns red. When methyl orange is used as an indicator with base, the color of the solution turns yellow.
As dilute hydrochloric is acidic in nature, when methyl orange is added to it, the color of the solution turns red.
.
.
.
After adding methyl orange to HCl, your solution will kinda look like this ↓↓↓
Methyl orange is used as an indicator with acid, the color of the solution turns red. When methyl orange is used as an indicator with base, the color of the solution turns yellow.
As dilute hydrochloric is acidic in nature, when methyl orange is added to it, the color of the solution turns red.
.
.
.
After adding methyl orange to HCl, your solution will kinda look like this ↓↓↓
More
VOTE
There are 2 theories of indicators which explain colour change .
1)Ostwald's Theory
According to this theory: (a) The colour change is due to ionisation of the acid-base indicator. The unionised form has different colour than the ionised form. (b) The ionisation of the indicator is largely affected in acids and bases as it is either a weak acid or a weak base.
In short it said that every indicator is itself a weak acid or weak base and thus colour change could be explained by the ionization equation of the indicator taking in consideration the common ion effect which is a consequence of Le Chatlier's Principle .
The Drawback of this theory : It failed to explain the structural changes .
2)The Modern Benzenoid Theory
It says that indicators exist in interconvertible forms - Benzenoid and Quinonoid . One form predominates in one medium and other in the other medium .
Quinonoid form is more deeper in colour than Benzenoid form .
In case of Methyl Orange it exists in Quinonoid form in Acidic medium , showing red colour and Benzenoid form in basic medium showing yellow colour.
There are 2 theories of indicators which explain colour change .
1)Ostwald's Theory
According to this theory: (a) The colour change is due to ionisation of the acid-base indicator. The unionised form has different colour than the ionised form. (b) The ionisation of the indicator is largely affected in acids and bases as it is either a weak acid or a weak base.
In short it said that every indicator is itself a weak acid or weak base and thus colour change could be explained by the ionization equation of the indicator taking in consideration the common ion effect which is a consequence of Le Chatlier's Principle .
The Drawback of this theory : It failed to explain the structural changes .
2)The Modern Benzenoid Theory
It says that indicators exist in interconvertible forms - Benzenoid and Quinonoid . One form predominates in one medium and other in the other medium .
Quinonoid form is more deeper in colour than Benzenoid form .
In case of Methyl Orange it exists in Quinonoid form in Acidic medium , showing red colour and Benzenoid form in basic medium showing yellow colour.
More
VOTE
The chemical formula of methyl orange is C14H14N3SO3Na. Its structure is given below:
The chemical formula of methyl orange is C14H14N3SO3Na. Its structure is given below:
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