Understanding the Reaction

The reaction you're describing is a double displacement reaction where sodium chromate (Na₂CrO₄) reacts with a source of chloride ions (like HCl) to produce sodium chloride (NaCl) and chromic acid (H₂CrO₄):

2 Na₂CrO₄ + 4 HCl → 4 NaCl + 2 H₂CrO₄

Stoichiometry

The balanced chemical equation tells us the mole ratios of the reactants and products:

* 2 moles of Na₂CrO₄ react to produce 4 moles of NaCl

Calculation

Since you have 2 moles of Na₂CrO₄, you can use the mole ratio to find the moles of NaCl formed:

(2 moles Na₂CrO₄) * (4 moles NaCl / 2 moles Na₂CrO₄) = 4 moles NaCl

Answer:

A total of 4 moles of NaCl will be formed when 2 moles of Na₂CrO₄ react completely.