Adding NaOH-sol'n to oxalic acid, C2H2O4, the colour (from colorless) has to become purple-blue at pH 8 to 10.
The indicator is used to measure the end point of titration. Methyl red and phenolphthalein are frequently used indicators in acid-base titration. Potassium permanganate can used as a self indicator in redox titrations where applicable.
Phenolphthalein is an acid base indicator - it does not show the end-point in a thiosulfate type titration. Starch gives a very sharp end-point from a blue-black to colorless end-point when titrating iodine with thiosulfate. Phenolphthalein would just not detect this change.
Type your answer here... Phenolphthaelin indicator changes its colour at 8.3 pH. But the end point of this reaction is at pH 7. In weak base Strong acid case the curve gives sharp change from 3.2 to 6.0 pH. Hence phenolphthalein indicator will not be advicable.
Change color
The function is to change color. This happens when all the H+ ( or H3O+) from the acid has been neutralized, an indicator in the sample will change
Phenolphtalein change colorless at pH < 8 to purple blue at pH > 8 to 10
The indicator is used to measure the end point of titration. Methyl red and phenolphthalein are frequently used indicators in acid-base titration. Potassium permanganate can used as a self indicator in redox titrations where applicable.
The easiest way is to add back some of the solution you were titrating. If phenolphthalein remains, it will react with the solution and change back to purple. Incidentally, phenolphthalein will always remain in the solution of the titration reaction - it changes color depending upon the pH of the solution, but the indicator itself is not affected by the titration reaction.
Phenolphthalein is an acid base indicator - it does not show the end-point in a thiosulfate type titration. Starch gives a very sharp end-point from a blue-black to colorless end-point when titrating iodine with thiosulfate. Phenolphthalein would just not detect this change.
Type your answer here... Phenolphthaelin indicator changes its colour at 8.3 pH. But the end point of this reaction is at pH 7. In weak base Strong acid case the curve gives sharp change from 3.2 to 6.0 pH. Hence phenolphthalein indicator will not be advicable.
Phenolphthalein is an indicator that undergoes a colour change from colourless to pink that begins at a pH of 8.0. So in the titration your performing the phenolphthalein will start to change colour at the point when the moles of acid equal the moles of base. Although this colour change occurs at a pH of 8.0 and not at a pH of 7.0 phenolphthalein is commonly used because of the distinctive colour change that occurs. Phenolphthalein is colourless in acids and pink/purple in base. It also turns orange in very strong acids.
Change color
Phenolphthalein changes from colorless to red in the range of pH = 8.0 to 9.6
You think probable to phenolphthalein used as a pH indicator.
The color does not change unless an indicator such as litmus or phenolphthalein is being used. If litmus the color change is blue to red If phenolphthalein the change is red to colorless
The function is to change color. This happens when all the H+ ( or H3O+) from the acid has been neutralized, an indicator in the sample will change
change in pH, changes the colour (of the indicator)