Multiple choice Soda ash is Na2HCO3 Na2CO3. H2O NaOH Na2CO3 Reveal answer Fill a bubble to check yourself D Correct answer Explanation Soda ash is the common name for anhydrous sodium carbonate, Na2CO3. Option A is baking soda (sodium bicarbonate), option B is washing crystals (hydrated sodium carbonate), and option C is caustic soda (sodium hydroxide).