Question

Complete and balance each acid-base reaction. a. \(\mathrm{H}_{3} \mathrm{PO}_{4}(a q)+\mathrm{NaOH}(a q) \rightarrow\) Contains three acidic hydrogens b. \(\mathrm{H}_{2} \mathrm{SO}_{4}(a q)+\mathrm{Al}(\mathrm{OH})_{3}(s) \rightarrow\) Contains two acidic hydrogens c. \(\mathrm{H}_{2} \operatorname{Se}(a q)+\mathrm{Ba}(\mathrm{OH})_{2}(a q) \rightarrow\) Contains two acidic hydrogens d. \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(a q)+\mathrm{NaOH}(a q) \rightarrow\) Contains two acidic hydrogens

Short answer

The short version of the answers for each acid-base reaction are as follows: a. \(H_{3}PO_{4}(aq) + 3NaOH(aq) \rightarrow Na_{3}PO_{4}(aq) + 3H_{2}O(l)\) b. \(3H_{2}SO_{4}(aq) + 2Al(OH)_{3}(s) \rightarrow Al_{2}(SO_{4})_{3}(aq) + 6H_{2}O(l)\) c. \(H_{2}Se(aq) + Ba(OH)_{2}(aq) \rightarrow BaSe(s) + 2H_{2}O(l)\) d. \(H_{2}C_{2}O_{4}(aq) + 2NaOH(aq) \rightarrow Na_{2}C_{2}O_{4}(aq) + 2H_{2}O(l)\)

Step-by-step solution

Identify the products

In an acid-base reaction, the products are usually a salt and water. In this case, the salt would be sodium phosphate, Na₃PO₄, and water H₂O. Step 2: Balance the equation

Balance the equation

The balanced equation for this reaction is: \[H_{3}PO_{4}(aq) + 3NaOH(aq) \rightarrow Na_{3}PO_{4}(aq) + 3H_{2}O(l)\] b. \(H_{2}SO_{4}(aq) + Al(OH)_{3}(s)\) Step 1: Identify the products

Identify the products

In this case, the products would be aluminum sulfate, Al₂(SO₄)₃, and water H2O. Step 2: Balance the equation

Balance the equation

The balanced equation for this reaction is: \[3H_{2}SO_{4}(aq) + 2Al(OH)_{3}(s) \rightarrow Al_{2}(SO_{4})_{3}(aq) + 6H_{2}O(l)\] c. \(H_{2}Se(aq) + Ba(OH)_{2}(aq)\) Step 1: Identify the products

Identify the products

Here, the products would be barium selenide, BaSe, and water H2O. Step 2: Balance the equation

Balance the equation

The balanced equation for this reaction is: \[H_{2}Se(aq) + Ba(OH)_{2}(aq) \rightarrow BaSe(s) + 2H_{2}O(l)\] d. \(H_{2}C_{2}O_{4}(aq) + NaOH(aq)\) Step 1: Identify the products

Identify the products

In this example, the products are sodium oxalate, Na₂C₂O₄, and water H₂O. Step 2: Balance the equation

Balance the equation

The balanced equation for this reaction is: \[H_{2}C_{2}O_{4}(aq) + 2NaOH(aq) \rightarrow Na_{2}C_{2}O_{4}(aq) + 2H_{2}O(l)\]

Key concepts

Chemical Equations

Chemical equations are a powerful way to express chemical reactions, showing the substances involved and their transformations. In an equation, reactants appear on the left side and products on the right, separated by an arrow. The reactants are the starting substances, while the products are the newly formed compounds after the reaction. These equations symbolize each substance using its chemical formula, providing a clear and concise way to represent complex transformations.

Writing a chemical equation involves identifying the substances involved and their phase of matter (solid, liquid, gas, or aqueous), indicated by symbols (s, l, g, aq). For acid-base reactions, the reactants often include an acid and a base, which react to produce a salt and water.

• Example: In the reaction of hydrogen phosphate (H₃PO₄) with sodium hydroxide (NaOH), sodium phosphate (Na₃PO₄) and water are formed.

Understanding chemical equations enables us to visualize the changes that occur during a reaction, providing a foundation to further explore and manipulate chemical processes.

Balancing Reactions

Balancing chemical reactions is a crucial step to ensure that the law of conservation of mass holds true. This law states that matter cannot be created or destroyed in a closed system. Therefore, the number of each type of atom on the reactant side must equal the number on the product side. Balancing involves adjusting the coefficients, which are the numbers placed before compounds in an equation, to make both sides equal.

Here’s a straightforward method for balancing:

• Write the unbalanced chemical equation.
• Count the number of each type of atom on both sides of the equation.
• Adjust the coefficients to have the same number of each atom on both sides.
• Ensure that the smallest whole numbers are used for coefficients.

For instance, in the reaction between sulfuric acid (H₂SO₄) and aluminum hydroxide (Al(OH)₃), we balance by adding coefficients: 3H₂SO₄ reacts with 2Al(OH)₃ to form Al₂(SO₄)₃ and 6H₂O. This adjustment balances the equation because the atoms of each element match on both sides.

Neutralization Reactions

Neutralization reactions are a type of acid-base reaction where an acid reacts with a base to produce water and a salt. Such reactions are important in many contexts, including chemical manufacturing and biological systems.

In a neutralization reaction, the acidic hydrogen ions (H⁺) from the acid combine with the hydroxide ions (OH⁻) from the base to form water (H₂O). The remaining ions from both the acid and base form a salt.

• Example: In the reaction between hydrocyanic acid (H₂Se) and barium hydroxide (Ba(OH)₂), the products are water and barium selenide (BaSe).

This type of reaction is exothermic, meaning it releases heat. Neutralization not only helps in neutralizing acidity or basicity but also provides insights into reaction stoichiometry and energy changes during chemical reactions.