A hydrodium ion is best thought of as a water molecule, combined with a positively charged hydrogen ion. In the case of a water molecule combining with a hydrogen ion, the resulting equation can be seen below:
{eq}H_{2}O\: + \: H^{+}\: \: \rightarrow \: \: H_{3}O^{+} {/eq}
The product of {eq}H_{3}O^{+} {/eq} is referred to as the hydronium ion. Due to its positive charge, hydronium is classified as a cation. Cations have achieved their positive charge by donating an electron to a solution, leaving the cation having fewer electrons than it has protons. This lack of electrons leads to a positive overall charge. Any time a neutral atom gains or loses electrons, the resulting particle is referred to as an ion.
A picture of a hydronium ion can be seen here:
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In this image, it can be seen that there are 3 hydrogen atoms and 1 oxygen. Since oxygen atoms will traditionally form -2 charged ions, and hydrogen typically forms +1 ions, the resulting charge of this combination of atoms equals a +1 charge.
Water and hydronium ions are very closely related. The only separation between the two of them is a hydrogen ion. A hydrogen ion is nothing more than a proton. It is relatively easy for a hydrogen ion to get attached to a water molecule in a solution creating hydronium. In short, anytime there is a proton that attaches to a water molecule, hydronium is created.
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Try it nowThe most common use of the term hydronium is during a discussion on whether solutions are acidic/basic. Hydronium is one of the two key ions that are measured to determine the pH of a solution, with the other being hydroxide. The pH of a solution is nothing more than a calculation done to measure how much hydronium ion is present inside of a solution. The equation below will be a key to help calculate the hydronium ion of a solution:
{eq}H_{3}O^{+}\: x\: OH^{-}\: =\: 1x10^{^{-14}} {/eq}
Both the hydronium and hydroxide ions are referenced in terms of concentrations in this equation. In words, this equation is saying that the hydronium ion concentration multiplied by the hydroxide ion concentration will always equal {eq}1x10^{^{-14}} {/eq}. By having the concentrations of either the hydronium ions or the hydroxide ions, the opposite type of ion's concentrations can be calculated from this equation by rearranging the formula algebraically.
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The pH scale is based on the logarithmic scale. The pH is equal to the negative logarithm of the hydrogen ion concentration. Being on the logarithmic scale means that a pH of 1 is actually 10 times stronger than a pH of 2. They are only a magnitude of 1 apart on the pH scale, but on the log scale, this equates to a factor of 10 difference.
Using math to calculate, the pH of a solution can be calculated using the following equation:
{eq}pH= -log(H^{ +}) {/eq}
The hydrogen ion in this formula is easily replaced with the hydronium ion, as they are interchangeable when referencing acidic solutions.
The log scale makes calculating the pH of a certain concentration of an acid very simple in many circumstances. For example:
In a case where an acidic solution has a concentration of {eq}1 x10^{-5} {/eq}, the pH of that particular solution can be found by looking at the absolute value of the exponent of the concentration, 5 in this case. Therefore, the pH of a solution that has a hydrogen ion concentration of 1x10^-5 is 5. If the exponent of that solution's hydrogen concentration was -11, the pH of the solution would be 11.
A pH scale ranges from 0 being the most acidic up to 14 being the least acidic. Any solution that has a pH greater than 7 is said to be basic.
In situations in which the concentrations are not 1x10 raised to the power of an exponent, using the -log function will also accurately calculate pH as well.
Depending on what needs to be calculated and which information is given, an alternative method of calculating hydronium ion concentration is available also. If a problem occurs in which the pH is known and the request is for the hydronium concentration, the following equation can be used to calculate the concentration:
{eq}(H_{3}O^{+})=10^{-pH} {/eq}
This formula would certainly need the use of a calculator in order to determine a solution, but it can be very useful.
Hydrodium ions are the combination of a water molecule and a hydrogen ion, resulting in the formula, {eq}H_{3}O^{+} {/eq}. Hydronium is the key to calculating whether a solution is acidic or basic. Solutions that have a pH value less than 7 are considered acidic, while solutions that have a pH greater than 7 are called basic.
Hydronium is classified as a cation due to its positive charge. The positive charge stems from a loss of an electron in order to form the ion. Hydronium has 1 less electron overall than it does protons.
Several equations are vital to understanding the calculations involved with pH and hydronium ion concentrations.
This would be used to calculate the concentration of either hydronium ions or hydroxide ions given one of the two.
This equation would be used to calculate the pH of a solution given the hydrogen/hydronium ion concentration.
This equation would be used to calculate the hydronium ion concentration of a solution when given the pH.
Conversely, although pH is the more commonly used measurement, in basic solutions, the hydroxide ion concentrations can easily be calculated with these formulas as well.
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Yes. Hydronium is a cation that has a formula of H3O+. Since it has a positive charge, it classifies as a cation.
H3O+ is extremely similar to H+, but they should not be considered identically the same thing. H3O+ only is present in aqueous solutions, while H+ ions can occur in several different circumstances.
H3O+ is the sign of an acid being present. The concentration of H3O+ determines the magnitude of the acidity of a solution.
H3O+ is most commonly referred to as a hydronium ion. It occurs when a hydrogen ion combines with a water molecule.
Hydronium is a cation that has a formula of H3O+. It often is made from a water molecule combined with a positively charged hydrogen ion.
Yes. Hydronium is a cation that has a formula of H3O+. Since it has a positive charge, it classifies as a cation.
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