Why does junior high school chemistry say that the pH of the solution is between 0 and 14?

Hello classmates, junior high school is generally hydrogen ion or hydroxide ion concentration of 1mol l. So the pH belongs to O to 14. In fact, the pH can be less than zero. Complete.

In the "Water"This is true in solution.

In organic solvents, it is possible to jump out of this range.

Convenient! If there is a high concentration of acid, it is generally no longer expressed in terms of pH, but only **mol l

Answer B Solution Guidance: When the pH is less than 7, the solution is an acidic solution, when the pH is greater than 7, the solution is an alkaline solution, and when the pH is equal to 7, the solution is a neutral solution pH is equal to 0, and it is easy to mistake this solution for neither acidic solution nor alkaline solution, and choose C In fact, the pH of the solution can not only be 0, but also negative, and the smaller the pH, the stronger the acidity When the pH is less than 7, the solution is an acidic solution, so the choice of b pH is equal to 0 may also mistake that there is no such solution and it is also wrong to choose D

Assuming that all of them are 1L of solution, the amount of oh- matter after mixing is +1= concentration of h+concentration and disturbance chain is 2x10 -14mol l Because of the group, according to the pH value calculation formula, pH = 14 -LG2, which is approximately equal to.

pH is the hydrogen ion concentration index, which refers to the ratio of the total number of hydrogen ions in a solution to the amount of total substances. A numerical value that indicates the degree of acidity or alkalinity of a solution, i.e. the negative value of the commonly used logarithm of the concentration of hydrogen ions contained.

Usually the pH is a number between 0 and 14.

For example, when the pH value is 1, it means that the concentration of hydrogen ions in the solution is 1 10 molar concentration;

When the pH value is 2, it means that the concentration of hydrogen ions in the solution is 1 100 molar concentration;

Similarly, when the pH value is 0, it means that the concentration of hydrogen ions in the solution is 1 molar concentration.

It can be seen that if there is more than 1 molar concentration of hydrogen ions in the solution, the pH value can be negative.

It should also be noted that the pH value can not only be an integer, but also a decimal number. For example, the pH value of ordinary mineral water is about ......

Here's how to do it:

1.If the solution is acidic.

Then directly find the negative logarithm of the H ion concentration in the acid solution, and the water is negligible at this time. 2.If it is an alkaline solution.

The concentration of oh- ions in the solution or trace is first required.

In use 10- 14

Divide by it. Calculate the h concentration. Namely.

Acidic medium water ionization h

Negligible. Alkaline medium water ionization oh-

Negligible. So HCl is an acid solution.

NaOH alkali solution.

HAC (I don't know what this is.) But it should be an acid solution.

Sell solution for alkali reeds.

Because you are tease the specific concentration of the group is not given.

So I can't count either.

Hope it helps.

Of course, the solution of pH 0 is a solution with a concentration of 1mol l of hydrogen ions, and in reality there are more powerful than this, for example, if you have a little 10mol l of sulfuric acid solution, this is smaller than pH 0, which is negative Similarly, alkaline solutions can also be understood in this way pH does not have to be 1 14, but the liquid that is connected in ordinary life is 1 14, and it is inconvenient to use pH to express things beyond this range, so it is not used much. So you don't see a situation where the pH is negative or greater than 14, let's imagine a glass of solution, and the concentration of hydrogen ions is.

0 000001mol L, then it is very inconvenient for you to remember this concentration, so there is a notation of pH 6, but if the concentration of hydrogen ions is 10mol L, it is very convenient, why do you have to change it to pH 1, there is a negative number, how troublesome So pH 0 and pH 14 are there, 0 is acidic, 14 is of course alkaline

Hello! Yes.

However, it is generally not used in this way.

Because the pH of 0 solution, the hydrogen ion concentration is 1mol LP14 solution, the hydroxide ion concentration is 1mol l, when the hydrogen ion or hydroxide is greater than 1mol l, it is more convenient to express the concentration directly than to use the pH.

When in doubt, please ask.

It may be acidic or alkaline.

The pH value refers to the negative logarithm of the concentration of [H]+ ions in the solution, i.e., -LG10 X Usually -x is used to express the pH value, generally we know that the pH value of water is 7, and the pH value containing other solutes and the PoH value of water are added to 14

When the pH value of the solution is 14, it can be seen that the [H]+ ion concentration of water is approximately 0, but the concentration of [H]- of water cannot be 0, that is, the water must have ionization decomposition, and the ionization number and concentration of [H]+ and [OH]- are the same, and the pH value and POH (alkalinity) are both 14

pH>7 is alkaline and POH>7 is acidic, which means that it may be a strong acid or a strong base.

The ion product of 25 degrees of water is 10 to the -14th power, so it is 14; If it is 100 degrees, the ion product is 10 to the power -12, it is not 14, but 12.

In fact, there is more than 14, but the commonly used is 1 14, pH value, look at the name "p" is the meaning of negative logarithm, "h" is the concentration of hydrogen, so ph means the negative logarithm of the concentration of h ions in the solution:

log(c(h+)) so at room temperature, when the h concentration is 1mol l (for example, in 1mol l of hydrochloric acid solution), the ph is 0, and no matter how strong it is, there is a negative pH. In the same way, in a super strong alkali solution, the pH may also exceed 14, indicating that the concentration of hydrogen ions is less than at this time.

1*10^（-14）mol/l。

1 14 is just a common pH range for a solution.

FeCl3, the semi-reaction equation is Fe3++E-=Fe2+, which is independent of H+ concentration.

The PBO2 half reaction is PBO2+2E-+4H+=PB2++2H2O, which is obviously related to the H+ concentration, that is, the pH value.