core practical 9: finding the Ka value for a weak acid

Question 1

method

Answer 1

• use volumetric pipette to trabsfer 25 cm3 of acid to a conical flask
• measure initial pH using a pH meter (calibrated using a buffer solution)
• add alkali in small amounts (2cm3) noting the volume added
• at each time, stire and measure pH
• repeat
• when closer to end point , use smaller intervals of 1 cm3
• add until alkali in excess
• sraw ph curve

Question 2

hep only applies for

Answer 2

weak acid strong base