Question

why cant we used baking soda directly? why do we need to add tartaric acid to it?

Answer 1

If baking soda is used directly then the dish being prepared (e.g. cake) will turn bitter. Tartaric acid is used to neutralise the effect of sodium carbonate..
NaHCO3 + H+(from any acid) -----> CO2 + H2O + Sodium salt of that acid...

Hope it helps...
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