# Which method has the highest yield of calcium sulfate?

I'm not sure which of following two methods will give better yields for $$\ce{CaSO4}$$:

A. Add dilute $$\ce{HNO3}$$ to $$\ce{CaCO3}$$, followed by dilute $$\ce{H2SO4}$$; or

B. Titrate aqeuous calcium hydroxide with dilute sulfuric acid.

I'm leaning towards Method B since it is easier to point out when the reaction is complete, and the yield would thus be close to 100%.

For Method A, however, any excess $$\ce{CaCO3}$$ would react with $$\ce{H2SO4}$$ and any excess $$\ce{Ca(NO3)2}$$ might undergo a displacement reaction where $$\ce{NO3-}$$ ions are displaced by $$\ce{SO4^2-}$$.

• A if yield is based on precipitation (compare calcium sulphate and hydroxide solubilities), B if on evaporation. Jun 6, 2021 at 17:05
• Consider that in A. you add an extra species that is not needed in the end, and in B., the only product besides gypsum is water. Jun 6, 2021 at 20:12
• Are you going to evaporate the leftover solution? Jun 11, 2021 at 13:58