You have acid reflux and you take teaspoon of sodium bicarbonate. Assuming that one gram of sodium bicarbonate made it down into your stomach, how many moles of acid could it neutralize?

2NaHCO3 + 2HCl ==> 2H2O + 2CO2 + 2NaCl

Convert 1 g NaHCO3 to moles. moles = grams/molar mass

Using the coefficients in the balanced equation, convert moles NaHCO3 to moles HCl. And you have your answer. You can convert this to grams HCl by multiplying moles x molar mass = grams HCl.