A chemist determines the fraction of magnesium that burns in air to make Mg3N2 by adding the ash for — Laboratory Chemistry Question
Question
A chemist determines the fraction of magnesium that burns in air to make Mg3N2 by adding the ash formed from a known mass of Mg ribbon into water, distilling the mixture into a known excess of hydrochloric acid, and back-titrating the excess HCl with NaOH to a methyl orange endpoint. Which error will cause the calculated fraction of magnesium nitride to be too high?
A.
The distillate is collected in a flask by itself and subsequently added to the HCl.
B.
Phenolphthalein is used as an indicator in place of methyl orange.
C.
The potassium hydrogen phthalate used to standardize the NaOH had absorbed some moisture from the air.
D.✓ Correct
When the HCl solution was drawn into the volumetric pipet used to dispense it, a large bubble was present.
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