A student prepares nitrogen dioxide gas (NO2\text{NO}_2NO2) in a school laboratory by reacting copper turnings with concentrated nitric acid (HNO3\text{HNO}_3HNO3) inside a fume cupboard.
The unbalanced chemical equation for this reaction is:
aCu(s)+bHNO3(aq)→cCu(NO3)2(aq)+dNO2(g)+eH2O(l) a\text{Cu}(s) + b\text{HNO}_3(aq) \rightarrow c\text{Cu(NO}_3)_2(aq) + d\text{NO}_2(g) + e\text{H}_2\text{O}(l) aCu(s)+bHNO3(aq)→cCu(NO3)2(aq)+dNO2(g)+eH2O(l)Which of the following rows correctly identifies the stoichiometric coefficients b b\,b and d d\,d in the balanced equation, and the key hazard classifications associated with concentrated nitric acid and nitrogen dioxide gas?
Coefficients: b=2,d=2b = 2, d = 2b=2,d=2
Concentrated HNO3\text{HNO}_3HNO3 hazards: Corrosive, Flammable
NO2\text{NO}_2NO2 hazards: Toxic, Hazardous to the environment
Coefficients: b=4,d=2b = 4, d = 2b=4,d=2
Concentrated HNO3\text{HNO}_3HNO3 hazards: Corrosive, Oxidising
NO2\text{NO}_2NO2 hazards: Toxic, Corrosive
Coefficients: b=4,d=2b = 4, d = 2b=4,d=2
Concentrated HNO3\text{HNO}_3HNO3 hazards: Flammable, Harmful
NO2\text{NO}_2NO2 hazards: Explosive, Toxic
Coefficients: b=2,d=1b = 2, d = 1b=2,d=1
Concentrated HNO3\text{HNO}_3HNO3 hazards: Corrosive, Oxidising
NO2\text{NO}_2NO2 hazards: Flammable, Harmful