Question

Predict the products of each reaction and write balanced complete ionic and net ionic equations for each. If no reaction occurs, write NO REACTION. (a) \(\mathrm{BaS}(a q)+\mathrm{NH}_{4} \mathrm{Cl}(a q) \longrightarrow\) (b) \(\mathrm{NaC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}(a q)+\mathrm{KCl}(a q)\) (c) \(\mathrm{KHSO}_{3}(a q)+\mathrm{HNO}_{3}(a q)\) (d) \(\mathrm{MnCl}_{3}(a q)+\mathrm{K}_{3} \mathrm{PO}_{4}(a q) \longrightarrow\)

Short answer

(a) Net ionic: \(\mathrm{S}^{2-}(aq) + 2\mathrm{NH}_4^{+}(aq) \longrightarrow 2\mathrm{NH}_3(g) + \mathrm{H}_2\mathrm{S}(g)\). (b) NO REACTION. (c) Net ionic: \(\mathrm{HSO}_3^{-}(aq) + \mathrm{H}^{+}(aq) \longrightarrow \mathrm{SO}_2(g) + \mathrm{H}_2\mathrm{O}(l)\). (d) Net ionic: \(\mathrm{Mn}^{3+}(aq) + \mathrm{PO}_4^{3-}(aq) \longrightarrow \mathrm{MnPO}_4(s)\).

Step-by-step solution

Predict the products of the first reaction (a)

In the reaction between barium sulfide (BaS) and ammonium chloride (NH4Cl), a double displacement reaction occurs, provided the reactants are in aqueous solution. The possible products are barium chloride (BaCl2) and ammonium sulfide (NH4)2S. However, since ammonium sulfide is unstable, it tends to decompose into NH3 and H2S.

Write the balanced complete ionic equation for reaction (a)

The complete ionic equation for reaction (a) is: \(\mathrm{Ba}^{2+}(aq) + \mathrm{S}^{2-}(aq) + 2\mathrm{NH}_4^{+}(aq) + 2\mathrm{Cl}^{-}(aq) \longrightarrow \mathrm{Ba}^{2+}(aq) + 2\mathrm{Cl}^{-}(aq) + 2\mathrm{NH}_3(g) + \mathrm{H}_2\mathrm{S}(g)\). This shows all species that are present in the solution as ions, except for the gases produced.

Write the net ionic equation for reaction (a)

The net ionic equation for reaction (a) shows only the species that undergo a chemical change: \(\mathrm{S}^{2-}(aq) + 2\mathrm{NH}_4^{+}(aq) \longrightarrow 2\mathrm{NH}_3(g) + \mathrm{H}_2\mathrm{S}(g)\). Barium and chloride ions are spectator ions and are not included in the net ionic equation.

Predict the products of the second reaction (b)

For reaction (b), sodium acetate (NaC2H3O2) reacts with potassium chloride (KCl), both of which are soluble in water and none of them form a precipitate or decompose, so no reaction takes place. Therefore, the products are the same as the reactants.

State no reaction for (b)

Since no reaction takes place for reaction (b), we write: NO REACTION.

Predict the products of the third reaction (c)

For reaction (c), potassium hydrogen sulfite (KHSO3) reacts with nitric acid (HNO3). This is an acid-base reaction where the hydrogen sulfite ion is the base and nitric acid is the acid. The products are potassium nitrate (KNO3) and sulfuric acid (H2SO4), but the latter may decompose to give SO2 and water.

Write the balanced complete ionic and net ionic equations for (c)

The complete ionic equation for (c) is: \(\mathrm{K}^{+}(aq) + \mathrm{HSO}_3^{-}(aq) + \mathrm{H}^{+}(aq) + \mathrm{NO}_3^{-}(aq) \longrightarrow \mathrm{K}^{+}(aq) + \mathrm{NO}_3^{-}(aq) + \mathrm{SO}_2(g) + \mathrm{H}_2\mathrm{O}(l)\). The net ionic equation is: \(\mathrm{HSO}_3^{-}(aq) + \mathrm{H}^{+}(aq) \longrightarrow \mathrm{SO}_2(g) + \mathrm{H}_2\mathrm{O}(l)\).

Predict the products of the fourth reaction (d)

Reaction (d) involves manganese(III) chloride (MnCl3) reacting with potassium phosphate (K3PO4). This will result in the formation of a precipitate, which is manganese(III) phosphate (MnPO4), while the potassium and chloride ions will remain in solution.

Write the balanced complete ionic and net ionic equations for (d)

The complete ionic equation for (d) is: \(\mathrm{Mn}^{3+}(aq) + 3\mathrm{Cl}^{-}(aq) + 3\mathrm{K}^{+}(aq) + \mathrm{PO}_4^{3-}(aq) \longrightarrow \mathrm{MnPO}_4(s) + 3\mathrm{Cl}^{-}(aq) + 3\mathrm{K}^{+}(aq)\). The net ionic equation is: \(\mathrm{Mn}^{3+}(aq) + \mathrm{PO}_4^{3-}(aq) \longrightarrow \mathrm{MnPO}_4(s)\).

Key concepts

Double Displacement Reaction

Chemical reactions are like dances between atoms where they exchange partners. A double displacement reaction, also known as a metathesis reaction, is a type of dance where two compounds swap parts, resulting in the formation of two new compounds.

Imagine two couples, where partners switch to form new pairs. Similarly, in our textbook example (a), barium sulfide (BaS) and ammonium chloride (NH4Cl) are the two couples. Barium (Ba2+) pairs up with chloride (Cl-), while the ammonium (NH4+) gets together with sulfide (S2-). However, due to the instability of ammonium sulfide, it breaks down, which is like one couple deciding not to dance after all. In (d), manganese(III) chloride (MnCl3) exchanges parts with potassium phosphate (K3PO4), forming a solid partnership while the potassium (K+) and chloride (Cl-) ions are like wallflowers watching the dance.

Complete Ionic Equation

A story has many characters, and in chemistry, they come in the form of ions. A complete ionic equation provides a detailed narrative by showing all the characters (ions) present in a solution when a reaction takes place.

In example (a), every ion in the solution gets a role, even those that don't change partners, like barium and chloride ions. These ions are like extras in a film – they appear on screen but don't affect the plot. On the other hand, in the example of reaction (c), the complete ionic equation includes every ion from both potassium hydrogen sulfite (KHSO3) and nitric acid (HNO3), revealing what each is up to during the acid-base reaction.

Net Ionic Equation

If the complete ionic equation is the full story, the net ionic equation is the highlight reel. It cuts out the extras and focuses on the ions that undergo a chemical change – they're the lead actors.

For reaction (a), only sulfide (S2-) and ammonium (NH4+) make it to the net equation because they're the ones that truly change, forming new substances (NH3 and H2S). Similarly, in reaction (c), the net ionic equation only showcases the acid-base interaction between HSO3- and H+ because that's where the action is. Reaction (d) also has its highlights, with manganese (Mn3+) and phosphate (PO43-) being the main characters that come together to form a solid manganese(III) phosphate.

Spectator Ions

Not everyone gets to be the star of the show. In chemical reactions, spectator ions are like the crowd at a sporting event – they're present, but they don't participate. They watch the action without getting involved.

Spectator ions remain unchanged and appear on both sides of the reaction equation. In example (a), barium (Ba2+) and chloride (Cl-) ions are spectators. They're listed in the complete ionic equation, but since they don't undergo a chemical change, they're left out of the net ionic equation. It's important to identify these ions, so you know what's really driving the chemical storyline.

Precipitation Reaction

Imagine a cloud-heavy sky suddenly sending down a sheet of rain. In chemistry, a precipitation reaction is somewhat similar. When solutions containing certain ions are mixed, an insoluble substance, called a precipitate, can form and 'fall' out of the solution, just like rain from clouds.

Example (d) gives us a front-row seat to this phenomenon. Manganese(III) chloride and potassium phosphate mix, and like magic, solid manganese(III) phosphate (MnPO4) forms and separates from the solution. The other ions in the mix, potassium and chloride, stay dissolved – they're like spectators holding their umbrellas, unbothered by the rain of precipitate.

Acid-Base Reaction

Now think of an acid-base reaction as a polite exchange at a dinner party where a proton (H+) is passed between a guest (acid) and a host (base). The acid donates the proton, while the base accepts it. This elegant handover often produces water (H2O) and can result in the formation of a salt.

Reaction (c) showcases this genteel affair, with nitric acid (HNO3) offering a proton to potassium hydrogen sulfite (KHSO3), which graciously accepts. As they mingle, sulfur dioxide (SO2) and water are created, akin to the conversation and connections formed at our metaphorical party. The result? A transformed solution and a spectacular example of chemistry in action.