HCl is produced in the stomach which can be neutrabised by \(\mathrm{Mg}(\mathrm{OH})_{2}\) in the form of milk of mugnesia. How much \(\mathrm{Mg}(\mathrm{OH})_{2}\) is required to neutralise one mole of stomach acid? (a) \(29.16 \mathrm{~g}\) (b) \(34.3 \mathrm{~g}\) (c) \(58.33 \mathrm{~g}\) (d) \(68.66 \mathrm{~g}\)

Understanding chemical reactions is crucial when analyzing processes like neutralizing stomach acid. A chemical reaction involves the conversion of one or more substances into new substances with different properties. In the case of neutralizing stomach acid, the reaction occurs between hydrochloric acid (HCl), which is produced in the stomach, and magnesium hydroxide (\r\(\mathrm{Mg(OH)_2}\)), often found in antacids such as milk of magnesia.

In this specific reaction, hydrochloric acid and magnesium hydroxide combine to form magnesium chloride (\r\(\mathrm{MgCl_2}\)) and water (H2O). The balanced chemical equation clearly shows a 1:1 ratio between the reactants HCl and \r\(\mathrm{Mg(OH)_2}\). This ratio is essential to stoichiometry, as it allows us to calculate the exact amount of antacid needed to neutralize a given amount of stomach acid.

Molar mass calculation is another fundamental concept in chemistry crucial for solving stoichiometry problems. The molar mass of a substance is the mass of one mole of that substance, typically expressed in grams per mole (\r\(\text{g/mol}\)). It is equivalent to the sum of the atomic masses of all the atoms in a molecule of the substance.

For magnesium hydroxide, \r\(\mathrm{Mg(OH)_2}\), this involves adding together the atomic masses of magnesium (\r\(\mathrm{Mg}\)), oxygen (\r\(\mathrm{O}\)), and hydrogen (\r\(\mathrm{H}\)). By knowing the molar mass of \r\(\mathrm{Mg(OH)_2}\), we can convert moles to grams, which is a more practical unit of measure when neutralizing substances like stomach acid.

Stoichiometry is the section of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. In simpler terms, it tells you how much of each reactant you need to completely react with other reactants and how much of each product will be produced.

In the neutralization example, stoichiometry determines the precise amount of magnesium hydroxide to react with a specific amount of hydrochloric acid. Since the balanced chemical equation shows a 1:1 molar ratio between HCl and \r\(\mathrm{Mg(OH)_2}\), one mole of stomach acid will require one mole of magnesium hydroxide to neutralize it entirely. The stoichiometric calculations lead us to conclude that 58.319 grams of \r\(\mathrm{Mg(OH)_2}\) are needed to neutralize one mole of HCl, making the correct choice answer (c) 58.33 g.