Purpose: To find the pH and the concentration of the candy’s acid (citric acid).


  1. Measure ~5g of the candy powder (5.02g)
  2. Grind it with a mortar and pestle (4.88g)                     
  3. Add 50mLs of water to our candy powder and fill the burette with NaOH 
  4. Stir the solution until it’s fully mixed. 
  5. Take 10mLs of our solution out, put in small beaker and add 2-3 drops of phph. 
  6. Add NaOH (base) until clear/green solution (acid) turns pink and create table to put the information in.
  7. Repeat steps 4-5 three times but if the values are more than 0.5mL off from each other, do one more test and use average volume of the three trials for the calculations.

Materials :

  • more than 5g of acidic candy
  • scale
  • mortar and pestle
  • erlenmeyer flask
  • 50ml water
  • graduated cylinder
  • small beaker
  • burette
  • ring stand mixer
  • 50ml NaOH
  • phenolphthalein



M1V1 (NaOH) = M2V2 (C6H8O7)

(0.1M)(0.0026L) = M2(0.01L)

M2 = 0.026M

pH = -log(0.026) = 1.59

Our candy’s citric acid had a concentration of 0.026M and a pH of 1.6



Some errors that could’ve been made were through the transfer of the candy powder to the different containers because some could’ve been lost and that could have resulted in the calculations being off.