Titration of an Unknown Acid...

Question

What effect on the molar mass of the unknown acid would each of the following have... Would it make the calculated molar mass high, low, or would it have no effect?

1. Adding 5 drops of phenolphthalein instead of 1 drop... Answer: No effect.

2. Using a standard NaOH solution that has been left unstoppered for several days... Answer: Low

3. Failing to remove an air bubble in the tip of the burety containing the NaOH soltuion prior to titration... Answer: High

4. Failing to rinse down the unknown acid solution from the inside walls of the flask near the end of the titration... Answer: Low

5. Placing the unknown acid in a wet container prior to weighing it... Answer: High

Answer 1

These look ok to me except for #2. Rethink that one. For a monoprotic acid,
mL x M x millimolar mass = grams.