Why is the H OH product a constant

At a certain temperature, the product (kw) of [H] and [oh-] in water is a constant, and this constant is called the ion product of water (formerly known as the ion product constant). The ion product of water is also called the self-ionization constant of water.

After the ionization of water [H2O(L) H(AQ) OH-(AQ)] reaches equilibrium, the equilibrium constant is.

Water is a pure liquid, and [H2O] can be seen as a constant, so KW=[H][OH-]. The kw value is temperature dependent, at 25, kw = [h] [oh-] = 1 10-7 = 1 10 7 = 1 10-14. For the sake of computational simplicity, this value is often used as the ion product of water at room temperature.

In a dilute aqueous solution of a substance, [H2O] and pure water are almost identical to [H2O], so KW is also almost equal. This means that in any acidic (or alkaline) solution, both h and oh- are present, but the relative magnitude of [h] and [oh-] is different. At room temperature, the product of [h] and [oh-] is equal to 1 10-14.

Therefore, the acidity or alkalinity of an aqueous solution is expressed only by the concentration of one ion (H or OH-).

Water is a amphoteric substance that can both release and accept protons. Water also dissociates weakly to a certain extent, and protons are transferred from one water molecule to another, forming H3O+ and OH-.

When equilibrium is reached, the dissociation constant of water is obtained

or [H2O+][OH-]=K1[H2O]2

Since the degree of dissociation of water is extremely small, the value of [ho] can be regarded as a constant, such that k1[h2o]2 is equal to another new constant, kw, then.

h3o+][oh-]=kw

kw is called the ion product constant of water, which is referred to as the ion product of water. The above equation shows that the product of the concentration of hydrogen ions in water and the concentration of hydroxide ions is a constant at a certain temperature (Table 3-1). At 25 hours, it was experimentally determined that [H3O+] and [OH-] in pure water were respectively.

The hydrated ion H3O+ is usually abbreviated as H+, so that at room temperature:

Table 3-1 Ion product of water at different humidity.

Temperature kw

iTemperature kw

k=h+][oh-]= (3-2)

Since water absorbs a lot of heat during dissociation, the temperature increases, and the degree of water dissociation and kw also increases.

The principle of ion product of water applies not only to pure water, but also to all dilute aqueous solutions. In any dilute aqueous solution, the product of [H+] and [OH-] is always equal to kw, regardless of how they change.

He called it the ion product constant of water, and the ion product of water is a constant at a certain temperature.

This is determined by the ionization capacity of water.

Because in ordinary solutions, water is the vast majority.

This is the result of multiple tests at a certain temperature, and it is a constant, and you can understand it as a property of water, just like the freezing point of water is 0 degrees, so the question you ask is equivalent to why the freezing point of water is 0 degrees.

You say why,

In acid solutions (such as hydrochloric acid), because the solute in the solution is acid, which inhibits the ionization of water, only a weak part of the hydrogen ions in the solution is ionized by water, so it is ignored. In salt solution, such as FeCl3 solution, the hydrolysis is acidic, and the ionized hydrogen ions and hydroxide ions are the same, but OH- and Fe3 combine into iron hydroxide to promote water ionization, but the KW in the solution is still 10 -14. In fact, to put it bluntly, it is the balance of water ionization, which is divided into two categories, that is, acid-base inhibition and salt promotion, and it is OK to find the source and analyze.

The hydrogen ions and hydroxide ions in 1*10 -14 do not refer to the ionization of only water, but the sum of all the two ions that can be produced in an aqueous solution, but the product of the two in the solution is quantitative.

100mol/l?The maximum concentration of hydrochloric acid solution is about 37%, if I'm not mistaken. This assumption is not valid, and it can only be thought of as an ideal situation.

Under normal circumstances, the larger C(H+), the smaller C(OH-), even if C(H+)=100 times the constant of the mol (sorry, I forgot it for too long after graduation, it seems to be N), then C(OH-)=10 to the minus 16th power The constant of the mol, small is a small point, and it is theoretically possible, which is the ideal situation, and the product is a constant. Of course, the influence of temperature is not considered (generally except for research, just doing questions).

It means that the product of H+ OH- ionized by water in solution is a constant, which is called the ion product of water. It's about temperature.

The product of c(h+) and c(oh-) in aqueous solution, dilute acid and alkali solution is a constant, which is called the ion product constant, which is expressed by kw. kW = minus 14 power of 10 at room temperature, it is only related to temperature. When the temperature is constant, c(h+) is inversely proportional to c(oh-).

The acid solution is equivalent to adding acid to the water, and the increase of c(h+) inhibits the ionization of water, and the ionization of water is c(oh-)=10-16, so kw=100*10(-16)=10 to the minus 14th power.

The acidity reduction of water at room temperature is neutral, h+=oh-, while at room temperature they do not change, so the ion product constant of water does not change!

I think this is an experimental law, discovered through experimental measurements!

It's like a law we all know!

But you have to know: I can't help you why the height is constant, I can't help you!

What can be provided to you is that it changes with the temperature of the wax, and no other factors will act on him!

The ionic product constant of waterIt changes with temperature.

You can understand that this is a fundamental property of water, just as the earth is round, making it public that has been proven by a lot of experiments.

By the way, only at 25 degrees c(oh-)*c(h+)=10 -14

This product increases when the temperature increases, and decreases when it decreases.

This is a measured value.

At a certain temperature, the product (kw) of [h] and [oh-] in water is a constant, and this constant is called the ion product of water.

At 25, kw = [H][OH-]=1 10-7= 1 10 7=1 10-14

at other temperatures. The ion product of water will be different.

At 20 degrees Celsius, there is always c(oh-)*c(h+)=10 -14

c(oh-)*c(h+) is only temperature dependent.

This is an intrinsic property of a substance, just like why the solubility of a substance is fixed at a certain temperature.

is the ionic product constant of water, kw = c(h+)c(oh-)

This constant is only related to temperature.

Because kw=c(h+)*c(oh-) is actually the equilibrium constant of H2O ionization, and the equilibrium constant is only related to temperature, so the temperature is constant, and kw is constant.

There is a balance of water.

H2O = (reversible) = H+ +OH-

Equilibrium constant k=c(h+)*c(oh-) c(h2o)In a dilute solution, we consider the concentration of water to be constant, so c(h+)*c(oh-) is a constant at a certain temperature.

This is the definition of the ionic product of water.

kw=c(h+)*c(oh-)

Don't be discouraged when I was a freshman in high school and I was also confused when I first came into contact with science and chemistry, but I knew it when I did more than one topic. I'll explain patiently.

Take your topic to explain.

Because the ionization of water is only related to temperature (a constant of temperature).

When there is 10 -2 H+ in the solution, the ionization of water is inhibited by the H+ ionized by HCl.

Only about 10 -12 oh- and h+ ionization is the product of the concentration of h+ ions in the aqueous solution and the concentration of oh- in the aqueous solution is 10 -14 is constant.

After figuring it out above, let's look at the bottom below.

Originally, water is also ionized by 10 -12 mol H+, but the concentration of H+ ionized with HCl is negligible.

This is the ionic product constant of water, which is only related to temperature and not to reactants.

Because water is an absolute amount compared to other solutes, the concentration of molecular water is considered as a constant, so the ion product of water is a constant.

HCl is almost completely ionized in water, and the concentration of hydrogen ions produced is much greater than the contribution of water, so the hydrogen ions produced by water ionization are negligible.

Water electrolysis is also a balance.

k=〔h+〕*oh-〕/h2o〕

As with the equilibrium constant, the concentration of water at a certain temperature is a fixed value, which can be multiplied to the left of the equal sign, so the product of hydrogen ions and hydrogen yang root is a fixed value.

The fourteenth power of 10 divided by the twelfth power of 10 is too small to be negligible.

The correct answer is c

Analysis: The product of [H+][OH-] is the ionic product constant of water, which is only related to temperature (which increases with increasing temperature) and its value does not change as long as the temperature is constant. So the answer is c

c Regardless of the solution, when the temperature is constant, [H+][OH-] (i.e., the product of the total concentration of hydrogen ions and the total concentration of hydroxide ions in the solution) is a fixed value.

It is understood that when acid is added to water, water ionization is inhibited, and the hydrogen ion hydroxide ions ionized by water are less, but the acid ionizes a large number of hydrogen ions, so the product of the total hydrogen ion concentration and the total hydroxide ion concentration in the solution remains unchanged.

cccccccccccccccccccccc.The ionic product of water is a constant, and the constant does not change if the temperature does not change. Unless you add concentrated H2SO4 dissolved in water and violently exothermic, but the topic is not mentioned, it is better to treat the temperature as unchanged.

This is a chemistry problem, I don't know.