Titration

Tags

Chem/Reaction

Cegep/2

Word count

189 words

Reading time

2 minutes

Delivery of a measured volume of a solution of known concentration (titrant) into a solution being analyzed (analyte)

[!abstract]+ Equivalence point
Instant during titration where neutralisation of analyte is complete
Syn. stochiometric point

[!abstract] End point
Instant where the indicator changes colour

Examples

A student carries out an experiment to standardize (determine the exact concentration of) a sodium hydroxide solution. To do this, the student weighs out a 1.3009-g sample of potassium hydrogen phthalate (KHC8H4O4, often abbreviated KHP). KHP (molar mass 204.22 g/mol) has one acidic hydrogen. The student dissolves the KHP in distilled water, adds phenolphthalein as an indicator, and titrates the resulting solution with the sodium hydroxide solution to the phenolphthalein endpoint. The difference between the final and initial burette readings indicates that 41.20 mL of the sodium hydroxide solution is required to react exactly with the 1.3009 g KHP. Calculate the concentration of the sodium hydroxide solution.

Ions: $\mathrm{K}{\phantom{A}}^{+}\mathrm{HC}{\phantom{A}}_8\mathrm{H}{\phantom{A}}_4\mathrm{O}{\phantom{A}}_4{\phantom{A}}^{-}\mathrm{Na}{\phantom{A}}^{+}\mathrm{OH}{\phantom{A}}^{-}$
N.I.E: $\mathrm{HC}{\phantom{A}}_8\mathrm{H}{\phantom{A}}_4\mathrm{O}{\phantom{A}}_4{\phantom{A}}^{-}{\phantom{A}}_{(\mathrm{aq})}+\mathrm{OH}{\phantom{A}}^{-}{\phantom{A}}_{(\mathrm{aq})}⟶\mathrm{H}{\phantom{A}}_2\mathrm{O}{\phantom{A}}_{(\mathrm{l})}+\mathrm{C}{\phantom{A}}_8\mathrm{H}{\phantom{A}}_4\mathrm{O}{\phantom{A}}_4{\phantom{A}}^{2-}$

$$1.3009\mathrm{g}\cdot \frac{1\mathrm{mol}\mathrm{H}{\phantom{\mathrm{A}}}^{+}}{204.22\mathrm{g}}\cdot \frac{1\mathrm{mol}\mathrm{NaOH}}{1\mathrm{mol}\mathrm{H}{\phantom{\mathrm{A}}}^{+}}\cdot \frac{1}{41.20\mathrm{mL}}\cdot \frac{1000\mathrm{mL}}{1\mathrm{L}}=0.1546\mathrm{M}$$

Contributors

Ajitani Hifumi

Changelog

Last edited about 2 hours ago

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