What are limitations of a conclusion? i am doing a science lab write-up and under the conclusion it asks for limitations of the conclusion. what does this mean?

Using a value of ksp = 1.8 x 10-2 for the reaction pbcl2 pb+2(aq) + 2cl -(aq). if the value of ksp was determined to be only 1.2 x 10-2: too much solid has dissolved. additional precipitate is forming. the solution is unsaturated. the ions are now combining to reduce their concentrations.

If 22.5 liters of oxygen reacted with excess of hydrogen, how many liters of water vapor could be produced?

Measurements that have similar values are: a. usually accurate b. sometimes accurate c. always accurate d. never accurate