Question

Milk of magnesia, which is an aqueous suspension of magnesium hydroxide, is used as an antacid in the reaction below. How many molecules of HCl would have to be present to form 75.82 g of MgCl2?

Answer 1

To find the number of HCl molecules needed to form 75.82 g of MgCl2, calculate the moles of MgCL2 from its mass, use the stoichiometry of the balanced equation to find the moles of HCl required, and multiply by Avogadro's number to get the number of molecules. Correct option is

Step-by-step explanation:

To determine how many molecules of HCl would have to be present to form 75.82 g of MgCl2, we first need to write the balanced chemical equation for the neutralization reaction involving magnesium hydroxide (Mg(OH)2) and hydrochloric acid (HCl) to produce magnesium chloride (MgCl2) and water (H2O).

Mg(OH)2(s) + 2HCl(aq) → MgCl2(aq) + 2H2O(l)

The molar mass of MgCl2 is approximately 95.21 grams per mole. Using this and the mass of MgCl2 provided, we calculate the number of moles of MgCl2.

The stoichiometry of the reaction indicates that two moles of HCl react with one mole of Mg(OH)2, accordingly, two moles of HCl are required for each mole of MgCl2 produced. To find the number of molecules, we multiply the moles of HCl by Avogadro's number (6.022 x 10^23 molecules per mole).