Question

Complete this table for a solution: $$\begin{array}{c|c|c}\mathrm{pH} & {\left[\mathrm{H}^{+}\right]} & \text {Solution is } \\\\\hline<7 & & \\\\\hline & <1.0 \times 10^{-7} M & \\\\\hline & & \text { Neutral }\end{array}$$

Short answer

The completed table is as followed: \[\begin{array}{c|c|c}\text{pH} & \left[\mathrm{H}^{+}\right] & \text{Solution is} \\<7 & >1.0 \times 10^{-7} M & \text{Acidic} \ & <1.0 \times 10^{-7} M & \text{Basic} \ 7 & =1.0 \times 10^{-7} M & \text{Neutral}\end{array}\]

Step-by-step solution

Fill in the acidity or alkalinity of the solution

Looking at the first row with pH < 7, the solution is acidic. Then in the third row where it says 'neutral', the solution is not acidic nor basic, therefore the pH is 7.

Determine the concentration of hydronium ions based on pH

Since the pH < 7 in the first row, the concentration of \( \mathrm{H}^{+} \) ions will be > \(1.0 \times 10^{-7} M\). In the last row where it's neutral, the concentration of \( \mathrm{H}^{+} \) ions will be = \(1.0 \times 10^{-7} M\).

Determine the acidity or alkalinity based on concentration of hydronium ions

In the second row, where it states that \( \mathrm{H}^{+} \) ions is < \(1.0 \times 10^{-7} M\), the solution will be basic as the concentration of hydrogen ions is lower than that for a neutral solution.

Now we will fill out the entire table

Now that we have the information for each condition, we can fill in the entire table as such : \[\begin{array}{c|c|c}\text{pH} & \left[\mathrm{H}^{+}\right] & \text{Solution is} \\<7 & >1.0 \times 10^{-7} M & \text{Acidic} \ & <1.0 \times 10^{-7} M & \text{Basic} \ 7 & =1.0 \times 10^{-7} M & \text{Neutral}\end{array}\]

Key concepts

pH scale

Understanding the pH scale is essential in the world of acid-base chemistry. The pH scale ranges from 0 to 14 and is a way to measure how acidic or basic a solution is. It is an inverse logarithmic scale, meaning that as the hydronium ion concentration increases, the pH value decreases.
The scale can be broken down into simple sections:

• A pH less than 7 indicates an acidic solution.
• A pH of 7 is considered neutral, like pure water.
• A pH greater than 7 signifies a basic or alkaline solution.

Each unit of change represents a tenfold change in hydronium ion concentration. So a solution with a pH of 3 is ten times more acidic than one with a pH of 4. This intuitive scale helps chemists quickly assess the nature of a solution.

hydronium ion concentration

Hydronium ion concentration, represented as \([H^+]\), is the amount of hydrogen ions present in a solution. It plays a key role in determining the pH level. The relationship between pH and hydronium ions is given by the formula:\[pH = -\log_{10}[H^+]\]This formula shows that lower hydronium ion concentrations result in higher pH values, making the solution more basic. Conversely, higher hydronium ion concentrations lead to lower pH values, making the solution more acidic.
In practical terms:

• If \([H^+] > 1.0 \times 10^{-7}\) M, the solution is acidic.
• If \([H^+] = 1.0 \times 10^{-7}\) M, the solution is neutral.
• If \([H^+] < 1.0 \times 10^{-7}\) M, the solution is basic.

Understanding this relationship is crucial for solving problems related to acidity and alkalinity in chemistry.

neutral solution

A neutral solution is one of the simplest yet fundamental concepts in chemistry. It occurs when the pH of the solution is exactly 7. At this point, the concentration of hydronium ions is equal to the concentration of hydroxide ions.
In the equation we use:\[[H^+] = 1.0 \times 10^{-7} \text{ M}\]This balance means that the solution is neither acidic nor basic. Pure water is a classic example of a neutral solution. In real-world applications, maintaining a neutral pH is crucial in many biological and environmental processes. It serves as a reference point for comparing other solutions.
Whether dealing with bodily fluids or environmental water samples, understanding the properties of a neutral solution is essential for accurate assessments and problem-solving in chemistry.