[clout90265]

Today, I was titrating just for fun and pipetted five 25.00 milliliter samples of hydrochloric acid and transferred each sample to an Erlenmeyer flask, diluted it with distilled water, and added a few drops of phenolphthalein to each. Each sample was then titrated with a sodium hydroxide solution to the appearance of the first permanent faint pink color.

Out of my 5 samples, 4 of them were roughly 36.22ml of NaOh needed but the FIRST sample was 35.22ml
 ?!!!

What the heck did i do wrong? not rinse something? not enough indicator? too much water? misread?

Thanks in advance!


 

[mini]

the visual judgment of the analyst can account for an error usually