Required practical 1 -Titration

Question 1

How do you reduce uncertainty when using burette

Answer 1

Use a larger mass of solid OR more dilute acid

So a larger titre will be needed OR larger volume of HCL is read

Question 2

Describe the method, including apparatus and practical details, that the student should use to
prepare the solution.

Answer 2

STAGE 1
weigh mass of bottle containing solid
pour solid into beaker ,reweigh bottle
record difference in mass

STAGE 2
Add distilled water
stir with glass rod
until all solid is dissolved

STAGE3

Question 3

Describe the general method of titration

Answer 3

rinse equipment (burette with acid, pipette with alkali, conical flask with distilled water)
•pipette 25 cm3 of alkali into conical flask
•touch surface of alkali with pipette ( to ensure correct amount is added) •adds acid solution from burette
•make sure the jet space in the burette is filled with acid
•add a few drops of indicator and refer to colour change at end point
•use a white tile underneath the flask to help observe the colour change
•add acid to alkali whilst swirling the mixture and add acid drop wise at end point •note burette reading before and after addition of acid
•repeats titration until at least 2 concordant results are obtained- two readings within 0.1 of each other

Question 4

what indicators should be used if HCL or NAOH are used

State colour change at end point

Answer 4

HCL-methyl orange. yellow–>red
End point:orange

NAOH-phenolphthalein. pink–>colourless
Endpoint:colourless