Confirmation of errors regarding rinsing in Nitrogen/Fertiliser experiment

[VCEMan94]

Just need someone to confirm whether im right for this
(The prac is using back titration to find the amount of Nitrogen in Fertiliser)

How would the following affect your experiment:
Burette, pipette and conical flask are rinsed with the wrong solution i.e water

Burette - HCl will be diluted, thus it will appear that more will be needed to achieve equivalence point. This will mean that you will get a smaller amount for the NaOH reacting initially and subsequently the amount of NH4+. This will mean that you will have an overestimation of the amount of Nitrogen.

Pipette - NaOH will be diluted, thus it will appear that less HCl will be needed to achieve equivalence point. This will mean that you will get a larger amount for the NaOH reacting initially and subsequently the amount of NH4+. This will mean that you will have an underestimation of the amount of Nitrogen.

Conical Flask - No effect as the mass of the fertilizer as been weighed already, so the concentration will be same when you measure out 250mL. The water is used to dissolve the fertilizer sample anyway. NaOH already has fixed number of moles?

[VCE247]

Burette and pipette seem right
explanation seems obvious for burette, pipette with water would mean a diluted initial NaOH, which would mean that all the following results would be smaller, and you would get an underestimation

not sure about conical flask since it contains both the fertilizer solution and NaOh

probably should get one of the chem pros on here to confirm what ive said though

[man0005]

VCE247 seems right...would like to know about the conical flask though as well
hopefully someone helps soon D: sac tomorrow D:

[VCEMan94]

hmm anyone have any idea on the conical flasks?

[Water]

Conical Flask will have no effect , as the solutions will still have the same amount of mole, with the same amount of titre required.

[VCEMan94]

were the others correct as well?

[Water]

Looks right to me, by your end answers of over and underestimation xD.