The amount of sodium hydrogen carbonate, `NaHCO_(3)`, in an antacid tablet is to be determined by dissolving the tablet in water and titrating the resulting solution with hydrochloric acid. Which indicator is the most appropriate for this titration ?
`{:("Acid", " "K_(a)),(H_(2)CO_(3),2.5xx10^(-4)),(HCO^(-3),2.5xx10^(-8)):}`
A. methyl orange, `pK_(In)=3.7`
B. bromothymol blue, `pK_(In)=7.0`
C. phenolphthalein,`pK_(In)=9.3`
D. alizarin yellow `pK_(In)=12.5`
