What happens when HCl is titrated with NaOH?
During the course of the titration, the titrant (NaOH) is added slowly to the unknown solution. As it is added, the HCl is slowly reacted away. The point at which exactly enough titrant (NaOH) has been added to react with all of the analyte (HCl) is called the equivalence point.
Which indicator is used in the titration of NaOH and HCl?
phenolphthalein
For a weak acid vs strong alkali titration, phenolphthalein is the most suitable indicator. This is so because the last drop of added alkali brings the pH of the solution in the range in which phenolphthalein shows sharp colour change.
Why does HCl turn pink when NaOH is added?
If hydrogen ions (H+, as found in an acid) were added to the pink solution, the equilibrium would switch, and the solution would be colorless. Adding hydroxide ions (OH-, as found in bases) will change the phenolphthalein into its ion and turn the solution pink.
What is observed when sodium hydroxide is added to hydrochloric acid and phenolphthalein?
On adding nearly 5 mL sodium hydroxide solution to the mixture of hydrochloric acid and phenolphthalein solution, the colour of the mixture changes to pink. On addition of hydrochloric acid solution to the pink solution, the colour starts fading gradually and finally the solution becomes colourless.
How is titration performed?
A titration is a technique where a solution of known concentration is used to determine the concentration of an unknown solution. Typically, the titrant (the know solution) is added from a buret to a known quantity of the analyte (the unknown solution) until the reaction is complete.
Why do we use NaOH in titration?
Sodium hydroxide is used in titration if the unknown sample solution is acidic because bases are used to neutralize acids.
Which indicator is best for titration?
indicator phenolphthalein
The indicator phenolphthalein, whose range spans from pH 8 to 10, therefore makes a good choice for this type of titration. If you don’t know the pH change around the equivalence point of your titration, consult a general chemistry textbook.
Why does the pink color disappear in a titration?
The pink colour disappears in the titration because it is an indication that the reaction is reaching its endpoint and the reaction between the titrant and the sample are complete.
Why does the indicator change color in titration?
The color change of a pH indicator is caused by the dissociation of the H+ ion from the indicator itself. Recall that pH indicators are not only natural dyes but also weak acids. The dissociation of the weak acid indicator causes the solution to change color.
How does NaOH react with phenolphthalein?
Explanation: When the sodium hydroxide, which is a base, is mixed with phenolphthalein, it turns pink. When the base is neutralized by the acid, citric acid, which is present in lemons, the pink solution turns colorless.
What would be the colour of NaOH solution when phenolphthalein is added?
– NaOH (sodium hydroxide) is a base, phenolphthalein is added and the base turns pink in colour. After titrating out the base by any acid (drop by drop from the burette) the base gets colourless again.