JAMB - Chemistry (2017 - No. 40)
In the laboratory preparation of trioxonitrate (V) acid the nitrogen(iv) oxide formed as a by-product is removed by
further heating
adding concentrated H2SO4
cooling the acid solution with cold water
bubbling air through the acid solution
Explication
Bubbling of air through the acid solution removes deposited oxides of nitrogen.
Nitric acid is prepared in the laboratory by heating a nitrate salt with the concentrated acid.
NaNO3 + H2SO4 → NaHSO4 + HNO3
Vapours of nitric acid are condensed to a brown liquid in a receiver cooled under cold water. "Dissolved oxides of nitrogen" e.g NO2 are removed by redistillation or blowing a current of carbondioxide or dry air through the warm acid
Nitric acid is prepared in the laboratory by heating a nitrate salt with the concentrated acid.
NaNO3 + H2SO4 → NaHSO4 + HNO3
Vapours of nitric acid are condensed to a brown liquid in a receiver cooled under cold water. "Dissolved oxides of nitrogen" e.g NO2 are removed by redistillation or blowing a current of carbondioxide or dry air through the warm acid