Magnesium hydroxide, the active ingredient in milk of magnesia, neutralizes stomach acid, primarily hcl, according to the reaction mg(oh)2(aq)+2hcl(aq)→2h2o(l)+mgcl2( aq) what mass of hcl, in grams, is neutralized by a dose of milk of magnesia containing 3.26 g of mg(oh)2? express the mass in grams to three significant figures.

4.08 grams of HCl are neutralized by a dose of milk of magnesia containing 3.26 g of Mg(OH)₂.

Let's consider the neutralization reaction between HCl and Mg(OH)₂.

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

First, we will convert 3.26 g of Mg(OH)₂ to moles using its molar mass (58.32 g/mol).

The molar ratio of Mg(OH)₂ to HCl is 1:2. The moles of HCl that react with 0.0559 moles of Mg(OH)₂ are:

Finally, we will convert 0.112 moles of HCl to grams using its molar mass (36.46 g/mol).

4.08 grams of HCl are neutralized by a dose of milk of magnesia containing 3.26 g of Mg(OH)₂.

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Explanation:

For reaction stoichiometry problems like this, convert given data to moles and set up a ratio expression that relates to the balanced equation. That is ...

Given Rxn =>      Mg(OH)₂ + 2HCl => 2H₂O + MgCl₂

Given mass =>      3.26g = (3.26g)/(58g/mol) = 0.056 mole Mg(OH)₂

If from equation  1 mole Mg(OH)₂ reacts with 2 moles HCl

then,            0.056 mole Mg(OH)₂ reacts with x moles HCl

Setting up ratio and proportion expression ...

=> (1 mole Mg(OH)₂) /(0.056 mole Mg(OH)₂) = (2 moles HCl)/x

=> x = [2(0.056)/(1)] mole HCl neutralized = 0.112mole HCl (36g/mol)

= 4.05 grams of HCl neutralized.