[sega18]

An unknown solid compound containing Pb2+ ion was mixed with 15 mL of 2.0 M HNO3. The
mixture bubbled profusely. After complete reaction, it was found that 0.020 moles of CO2 were
produced and the original solid was completely consumed.
a) What is the chemical formula of the unknown solid?
b) Write a balanced net ionic equation for this reaction.
c) Calculate the mass of the original unknown solid.


How am I supposed to know that the solid is Lead(II) Hydrogen Carbonate and not Lead(II) Carbonate?

[Arkcon]

As written, I don't see how.  They should have given you a mass of solid.

[Borek]

While I agree question is ambiguous, I doubt bicarbonate exists. pK_sp for PbCO₃ is around 13, so it would most likely precipitate from solutions containing Pb²⁺ and HCO₃^-.

[AWK]

Except carbonate, lead forms also a few basic carbonates that are insoluble in water. Hence mass of sample is needed.

http://en.wikipedia.org/wiki/Lead_carbonate