Complete and balance the following double replacement reactions. Equation 1: HBr + NaOH ? Equation 2: 2HCl + Mg(OH)2 ?
The Correct Answer and Explanation is :
For the provided double replacement reactions:
Equation 1: HBr + NaOH
Hydrobromic acid (HBr) reacts with sodium hydroxide (NaOH) in a typical acid-base reaction. The hydrogen ion (H⁺) from HBr swaps places with the sodium ion (Na⁺) from NaOH. The sodium ion pairs with the bromide ion (Br⁻) to form sodium bromide (NaBr), and the hydrogen ion combines with the hydroxide ion (OH⁻) to produce water (H₂O). The balanced chemical equation for this reaction is:
[ \text{HBr} + \text{NaOH} \rightarrow \text{NaBr} + \text{H}_2\text{O} ]
Equation 2: 2HCl + Mg(OH)2
Hydrochloric acid (HCl) reacts with magnesium hydroxide (Mg(OH)₂). Here, two chloride ions (Cl⁻) from two molecules of HCl combine with magnesium ion (Mg²⁺) from Mg(OH)₂, and the hydrogen ions from HCl react with the hydroxide ions from Mg(OH)₂ to form water. This reaction balances as follows:
[ 2\text{HCl} + \text{Mg(OH)}_2 \rightarrow \text{MgCl}_2 + 2\text{H}_2\text{O} ]
Explanation
Double replacement reactions involve two ionic compounds where the cations and anions swap partners. These reactions are common in solutions and typically result in the formation of a precipitate, a gas, or water. In both reactions mentioned, the products include water, highlighting the neutralization reaction between an acid and a base. Sodium bromide and magnesium chloride are the resultant ionic salts, which remain dissolved in the aqueous solution. These reactions demonstrate important acid-base neutralization principles, essential in various chemical and biological processes. The precise exchange of ions leads to new compound formations, pivotal in demonstrating the law of conservation of mass in chemistry.