Is a pH greater than 7 acidic or alkaline?

Is a pH value greater than 7 acidic or alkaline? This question should be familiar to all of us! Because when we were in junior high school, our chemistry teacher told us. So, is a pH value greater than 7 acidic or alkaline? My answer is that it is alkaline. If you want to know about this topic, you must have common sense. Therefore, we should increase our knowledge as much as possible in our daily life. Because learning never ends. Okay, that’s what I want to talk about today.

A pH value greater than 7 is alkaline. The hydrogen ion concentration index refers to the ratio of the total number of hydrogen ions to the total amount of substance in a solution. Its value is commonly known as pH, which represents the degree of acidity or alkalinity of the solution, that is, the negative value of the common logarithm of the hydrogen ion concentration. pH value is one of the most important physicochemical parameters of aqueous solutions. Anything involving the natural pH of aqueous solutions and the acidity and alkalinity of solutions. Chemical changes and production processes are related to pH value. Therefore, pH value measurement is required in industry, agriculture, medicine, environmental protection and scientific research. The pH value of water is the negative logarithm of the activity of hydrogen ions in water, expressed as: pH=-lg[H+]. The pH value is sometimes also called the hydrogen ion index. Since the value of hydrogen ion activity is often very small, it is inconvenient to use, so the pH value or pH test paper is used as an indicator to judge the acidity and alkalinity of aqueous solutions. Moreover, the negative logarithm of hydrogen ion activity can indicate the magnitude of the change in acidity and alkalinity, which is very convenient to apply, and thus we can obtain (at 25°C):

⑴Neutral aqueous solution, pH=7

⑵ Acidic aqueous solution, pH <7, the smaller the pH value, the stronger the acidity;

⑶ Alkaline aqueous solution, pH>7, the larger the pH value, the stronger the alkalinity.

At standard temperature (25°C) and pressure, an aqueous solution with a pH of 7 (such as pure water) is neutral. This is because the product of the concentrations of hydrogen ions and hydroxide ions naturally ionized by water at standard temperature and pressure (the ion product constant of water) is always 1×10-14, and the concentrations of both ions are 1×10-7 mol/L. A small pH value indicates that the concentration of H+ is greater than the concentration of OH-, so the solution is highly acidic, while an increased pH value indicates that the concentration of H+ is less than the concentration of OH-, so the solution is highly alkaline. Therefore, the smaller the pH value, the more acidic the solution is; the larger the pH value, the more alkaline the solution is.

A pH value greater than 7 is acidic or alkaline. The answer is definitely alkaline. I'm sure you all think that the issue we are going to talk about today is very simple. In fact, I still think that today's issue is very simple. As long as we have a little common sense we know what the answer is. Therefore, there is never too much knowledge, so let’s all study hard. You all know whether a pH value greater than 7 is acidic or alkaline.