How many atoms of the element with atomic number 11 are in the reactants of the given formula? 2 NaCl + H2SO4 → 2 HCl + Na2SO4

The number of Na atoms in the reactants = 2

Every chemical reaction involves compounds that can act as reactants or products

The reactants will react to produce products

The reactants are usually written on the left side of the reaction, while the products on the right side of the reaction

Reaction

2 NaCl + H₂SO₄ → 2 HCl + Na₂SO₄

The element with atomic number 11  = Na(Natrium)

The number of atoms of the element that reacts or is produced can be seen from the reaction coefficient and the number of atoms in the compound

Na in NaCl = 1 atom

From equation, cofficient for NaCl = 2, so number of atoms of Na=2 x 1 = 2