Titration Guide

What is the purpose of a titration?

to determine the unknown concentration of a solution by reacting it with a solution of known concentration

What type of reaction is commonly used in titrations?

acid-base neutralisation reaction

What is the role of an indicator in titration?

to show when the endpoint has been reached through a colour change

What apparatus is used to accurately deliver the titrant?

a burette

What apparatus is used to measure an exact volume into the conical flask?

a pipette

Why must the burette be rinsed with the solution being used?

To avoid dilution and contamination of the solution

Why must the pipette be rinsed with the solution being measured?

to prevent dilution of the solution

Why should the funnel be removed from the burette before titration?

extra drops may enter the burette and alter the titre

Why are air bubbles removed from the burette tip?

Air bubbles cause inaccurate volume measurements

How should burette readings be recorded?

to 2 d.p and nearest 0.05mL

What is the meniscus?

the curved surface of liquid in glassware

How should the meniscus be read?

at eye level from the bottom of the curve

Why is a white tile placed under the flask?

to observe the indicator colour change more clearly

What is the purpose of a rough titration?

to estimate the approximate endpoint

Why is the conical flask continuously swirled during titration?

To ensure the solutions mix completely

When should solution be added drop-by-drop?

near the endpoint

What is the endpoint in a titration?

the point where the indicator permanently changes colour

What colour change does the phenolphthalein show in titrations?

pink to colourless or colourless to pink

What is a titre?

The volume delivered from the burette during a titration

What is the formula for titre?

Titre = Final burette reading - initial burette reading

What are concordant titres?

Titres that are very close in value, usually within ±0.10–0.20 mL

Why are concordant titres important?

they indicate reliable and precise results

Which titres are used to calculate the average titre?

only condordant titres

Why must volumes be converted to litres in calculations?

Because concentration units use molL^-1

What is the formula for calculating moles in titration?

n=cV

What does “n” represent in the formula n = cV

number of moles

What does the “c” represent in the formula n = cV?

concentration in molL^-1

What does “V” represent in the formula n = cV?

volume in litres

Why must a balanced chemical equation be used?

to determine the mole ratio between reactants

What is a mole ratio?

the ratio of coefficients in a balanced equation

What formula is used to calculate concentration?

c = n/V

Why are significant figures important in titration calculations?

they reflect the precision of measurements

What is a random error in titration?

an unpredictable variation affecting precision

example of a random error in titration

inconsistent endpoint judgement

What is a systematic error in titration?

a consistent error causing measurement to shift in one direction

example of systematic error

air bubbles in the burette tip

How does overshooting the endpoint affect titres?

it increases titre volume

Why are the flask walls washed down with distilled water during titration?

to ensure all reactants enter the solution

Why is distilled water added to the conical flask acceptable?

it does not change the number of moles present

What improves the accuracy of the titration results>

careful drowse addition near the endpoint and obtaining concordant titres