Titrating Carbonates with Alternative Indicator

The titration of carbonates (typically sodium carbonate) involves a weak base vs a strong acid (hydrochloric acid 0.1N). Color change results are quite subjective if you just use a simple methyl orange, as the color change is very gradual. A good alternative is mixed methyl orange-xylene cyanole FF.

This alternative will give a sharper color change within a narrower pH scale, and the color will change from grey to violet with a minimal addition of titrant hydrochloric acid. Exaxol has this indicator available here, for your convenience.