Hcl And Naoh Neutralization Reaction

vii.18: Titration Experiment

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Titration Experiment

In the neutralization of hydrochloric acid by sodium hydroxide, the mole ratio of acid to base is ane:1.

\[\ce{HCl} \left( aq \right) + \ce{NaOH} \left( aq \right) \rightarrow \ce{NaCl} \left( aq \right) + \ce{H_2O} \left( l \right)\]

I mole of \(\ce{HCl}\) would be fully neutralized by i mole of \(\ce{NaOH}\). If instead the hydrochloric acrid was reacted with barium hydroxide, the mole ratio would be two:1.

\[2 \ce{HCl} \left( aq \right) + \ce{Ba(OH)_2} \left( aq \right) \rightarrow \ce{BaCl_2} \left( aq \right) + 2 \ce{H_2O} \left( fifty \right)\]

Now 2 moles of \(\ce{HCl}\) would exist required to neutralize one mole of \(\ce{Ba(OH)_2}\). The mole ratio ensures that the number of moles of \(\ce{H^+}\) ions supplied by the acrid is equal to the number of \(\ce{OH^-}\) ions supplied by the base. This must be the case for neutralization to occur. The equivalence bespeak is the bespeak in a neutralization reaction where the number of moles of hydrogen ions is equal to the number of moles of hydroxide ions.

In the laboratory, it is useful to have an experiment where the unknown concentration of an acrid or a base tin be determined. This tin can be accomplished by performing a controlled neutralization reaction. A titration is an experiment where a volume of a solution of known concentration is added to a volume of another solution in gild to determine its concentration. Many titrations are acid-base neutralization reactions, though other types of titrations can besides be performed.

In gild to perform an acid-base titration, the chemist must accept a way to visually discover that the neutralization reaction has occurred. An indicator is a substance that has a distinctly different color when in an acidic or basic solution. A commonly used indicator for strong acid-strong base titrations is phenolphthalein. Solutions in which a few drops of phenolphthalein have been added turn from colorless to vivid pinkish as the solution turns from acidic to basic. The steps in a titration reaction are outlined below.

A measured volume of an acid of unknown concentration is added to an Erlenmeyer flask.
Several drops of an indicator are added to the acid and mixed by swirling the flask.
A buret is filled with the base of operations solution of known molarity.
The stopcock of the buret is opened and base is slowly added to the acid while the flask is constantly swirled to ensure mixing. The stopcock is closed at the exact point which the indicator but changes color.

The standard solution is the solution in a titration whose concentration is known. In the titration described in a higher place the base solution is the standard solution. It is very of import in a titration to add the solution from the buret slowly so that the point at which the indicator changes color tin can be found accurately. The end indicate of a titration is the signal at which the indicator changes colour. When phenolphthalein is the indicator, the end betoken will exist signified by a faint pink colour.

CK12 Screenshot 21-17-1.png — Figure \(\PageIndex{1}\): Phenolphthalein in basic solution. (CC By-NC; CK-12)

Summary

Definitions are given for equivalence point, titration, and indicator.
The process for carrying out a titration is described.

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