Question

Write net ionic equations for the reactions that take place when aqueous solutions of each pair of substances is mixed. a. sodium cyanide and nitric acid b. ammonium chloride and sodium hydroxide c. sodium cyanide and ammonium hydroxide d. potassium hydrogen sulfate and lithium acetate e. sodium hypochlorite and ammonia

Short answer

a. CN^- + H^+ → HCNb. NH4^+ + OH^- → H2O + NH3c. Reaction does not proceed (no net ionic equation).d. Reaction does not proceed (no net ionic equation).e. OCl^- + NH3 + H2O → NH2Cl + OH^-

Step-by-step solution

Write the balanced molecular equation for sodium cyanide and nitric acid

First, write down the molecular equation: NaCN(aq) + HNO3(aq) → NaNO3(aq) + HCN(aq). Next, balance the equation. It is already balanced as written.

Write the net ionic equation for the reaction of sodium cyanide and nitric acid

Identify the ions that change during the reaction. Sodium and nitrate ions are spectator ions and do not participate in the reaction. The net ionic equation is: CN^-(aq) + H^+(aq) → HCN(aq).

Write the balanced molecular equation for ammonium chloride and sodium hydroxide

First, write down the molecular equation: NH4Cl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) + NH3(g). Balance the equation if needed. The equation is already balanced.

Write the net ionic equation for the reaction of ammonium chloride and sodium hydroxide

Identify the changing species, the sodium and chloride ions are spectator ions. The net ionic equation is: NH4^+(aq) + OH^-(aq) → H2O(l) + NH3(g).

Write the balanced molecular equation for sodium cyanide and ammonium hydroxide

First, write the molecular equation: NaCN(aq) + NH4OH(aq) → NaOH(aq) + NH4CN(aq). Balance the equation if needed, it is already balanced.

Write the net ionic equation for the reaction of sodium cyanide and ammonium hydroxide

As all species are present as ions in solution, and there is no formation of a precipitate, gas, or weak electrolyte from strong electrolytes, no reaction occurs. Therefore, no net ionic equation is written; all species are spectators.

Write the balanced molecular equation for potassium hydrogen sulfate and lithium acetate

Write the molecular equation: KHSO4(aq) + LiC2H3O2(aq) → LiHSO4(aq) + KC2H3O2(aq). Balance the equation if needed. It is already balanced.

Write the net ionic equation for the reaction of potassium hydrogen sulfate and lithium acetate

All ions remain in solution and there is no formation of a precipitate, gas, or weak electrolyte from strong electrolytes, so no reaction takes place. All species are spectator ions and hence no net ionic equation is given.

Write the balanced molecular equation for sodium hypochlorite and ammonia

First, write down the molecular equation: NaOCl(aq) + 2NH3(aq) → NaOH(aq) + NH2Cl(aq) + H2O(l). The equation should be balanced with respect to the number of atoms and charges.

Write the net ionic equation for the reaction of sodium hypochlorite and ammonia

Sodium ions are spectator ions. The net ionic equation is: OCl^-(aq) + NH3(aq) + H2O(l) → NH2Cl(aq) + OH^-(aq).

Key concepts

Chemical Reactions

Understanding chemical reactions is fundamental in chemistry. Reactions occur when substances interact to form new compounds, often accompanied by energy change. Most reactions happen in a sequence of smaller steps, not just one sudden change. A key aspect is identifying the reactants, which are the starting substances, and the products, the new substances formed.
In the case of net ionic equations, we focus on the ions in an aqueous solution that actively participate in the chemical reaction. For example, when sodium cyanide reacts with nitric acid, the products are sodium nitrate and hydrogen cyanide. By writing a net ionic equation, we isolate the essence of the chemical reaction, omitting the spectator ions.

Aqueous Solutions

Aqueous solutions are created when substances dissolve in water. These solutions can conduct electricity if they contain ions, which can then engage in chemical reactions. When writing chemical equations for reactions in aqueous solutions, it's crucial to understand solubility rules, as these determine which compounds dissolve and which form precipitates.
Substances in aqueous solutions break down into ions. For instance, sodium hydroxide (NaOH) dissolves in water to form sodium ions (Na^+) and hydroxide ions (OH^-). These ions sometimes recombine to form new substances or act as catalysts, promoting reactions without being consumed.

Spectator Ions

Spectator ions, as the name suggests, are the ions in a chemical reaction that do not participate in forming the products. They are 'spectators' to the reaction, remaining unchanged from reactants to products. Identifying spectator ions is a key step in simplifying chemical equations to their net ionic form.
For example, when mixing ammonium chloride and sodium hydroxide, the spectator ions are the sodium (Na^+) and chloride (Cl^-) ions. Understanding spectator ions helps us focus on the ions that directly take part in the reaction - this clarity is vital for learning chemical reactivity and for applications like titrations in analytical chemistry.

Balance Chemical Equations

Balancing chemical equations is the art of making sure that the number of atoms for each element is conserved through a reaction. It is based on the principle of conservation of mass. Each side of the reaction must have the same quantity of each type of atom. When you balance an equation, you ensure that the chemical equation is following the laws of chemistry.
In our textbook solutions, equations such as for the reaction of potassium hydrogen sulfate with lithium acetate are already balanced. Therefore, no additional steps were required for this part. Balancing equations is not just a formal requirement – it also reflects the stoichiometry of the reaction, which is necessary for predicting the quantities of reactants needed and products formed.