Question

If electricity of sufficient voltage is passed into a solution of potassium iodide in water, a reaction takes place in which elemental hydrogen gas and elemental iodine are produced, leaving a solution of potassium hydroxide. Write the unbalanced equation for this process.

Short answer

The unbalanced equation for the reaction is: \( KI + H_2O \to H_2 + I_2 + KOH \)

Step-by-step solution

Identify the reactants and products

In the given problem, the reactants are potassium iodide (KI) and water (H₂O). When electricity is passed through the solution, it produces elemental hydrogen gas (H₂), elemental iodine (I₂), and leaves a solution of potassium hydroxide (KOH).

Write the unbalanced equation

Now that we know the reactants and products of the reaction, we can write the unbalanced equation: KI + H₂O -> H₂ + I₂ + KOH This is the unbalanced equation for the given process.

Key concepts

Electrochemical Reactions

Electrochemical reactions involve the movement of electrons between species at an interface, often between electrodes and a solution. These reactions are key in converting chemical energy into electrical energy, and vice versa. In the case of potassium iodide in water, we apply electricity to drive the reaction, a process known as electrolysis. During electrolysis, electrical energy causes a non-spontaneous chemical reaction to occur.
Here's a quick breakdown of electrolysis in this context:

• Electrons flow from the anode (positive electrode) to the cathode (negative electrode).
• Potassium iodide (KI) splits into potassium ions (K⁺) and iodide ions (I⁻).
• Iodide ions lose electrons (oxidation) to form iodine (I₂) at the anode.
• Water splits at the cathode to form hydrogen gas (H₂) and hydroxide ions (OH⁻).

The overall effect is the decomposition of compounds using electric current, which illustrates the fascinating world of electrochemical reactions.

Balancing Equations

Balancing chemical equations is crucial because it maintains the law of conservation of mass, which states that mass cannot be created or destroyed in a chemical reaction. When we write a chemical equation, it must reflect the same number of atoms for each element on both sides of the equation.
The unbalanced equation from the exercise is:

• KI + H₂O → H₂ + I₂ + KOH

Start balancing by matching the count of each type of atom on both sides.

• Balance iodine first, as both reactants and products include I₂, which needs to be doubled to match I₂.
• Adjust coefficients to equalize hydrogen from water (H₂O) splitting into H₂ and forming KOH.
• Potassium must be balanced by ensuring it matches in both KI and KOH.

With these steps, you can achieve a balanced equation, ensuring equal atom counts across the reaction.

Inorganic Chemistry

Inorganic chemistry focuses on compounds that typically do not involve carbon-hydrogen bonds, which are characteristic of organic chemistry. Instead, it deals with a diverse range of substances, including metals, minerals, and organometallic compounds. The reaction involving potassium iodide is a classic example of an inorganic chemical reaction.
Key features of inorganic reactions often include:

• They involve ionic compounds, like KI.
• Reactions can include redox processes, where oxidation and reduction occur simultaneously.
• These reactions frequently occur under specific conditions, such as the application of electricity for electrolysis.

In the exercise, potassium iodide (KI) and water undergo transformation through the movement of electrons, leading to new inorganic products, like elemental iodine and potassium hydroxide. Inorganic chemistry enables us to harness the unique properties of these elements and reactions for various applications, from energy storage to material synthesis.