what is pH and what is its full form?

Answer 1

The concentration of hydrogen ions is commonly expressed in terms of the pH scale. Low pH corresponds to high hydrogen ion concentration and vice versa. A substance that when added to water increases the concentration of hydrogen ions(lowers the pH) is called an acid. A substance that reduces the concentration of hydrogen ions(raises the pH) is called a base. Finally some substances enable solutions to resist pH changes when an acid or base is added. Such substances are called buffers. Buffers are very important in helping organisms maintain a relatively constant pH.

Answer 2

Full Form Of Ph

Answer 3

ph stands for Potency of Hydrogen ion.

pH is a measure of the acidity or alkalinity of a solution. Solutions with a pH less than seven are considered acidic, while those with a pH greater than seven are considered basic (alkaline). pH 7 is considered neutral because it is the accepted pH of pure water at 25 °C, although, due to the self-ionization of water, this is not completely accurate. pH is formally dependent upon the activity of hydrogen[1] ions (H+),[2] but for very pure dilute solutions, the molarity may be used as a substitute with some sacrifice of accuracy.[3] Because pH is dependent on activity, a property which cannot be measured easily or predicted theoretically, it is difficult to determine an accurate value for the pH of a solution. The pH reading of a solution is usually obtained by comparing unknown solutions to those of known pH, and there are several ways of doing this.

The concept of pH was first introduced by Danish chemist S. P. L. Sørensen in 1909. The name, pH, has been purported to come from a variety of places including: pondus hydrogenii (Latin),[4] potentiel hydrogène (French), and potential of hydrogen (English).[5] However pH is actually a shorthand for its mathematical approximation: in chemistry a small p is used in place of writing − log10 and the H should more correctly be [H+], standing for concentration of hydrogen ions.

Answer 4

In 1909 Sorenson devised a scale on which the strenght of acid solutioon as well as basic solutions could be represented by making use of hydrogen ion concentration in them.
The strenght of an acid is measured on a scale of numbers called the pH scale.The pH scale has value 0 to 14

the full form of pH is Potency of hydrogen ion+

Answer 5

HI!
whenever we want to measure acidity, we r concentrated on the concentration of H+ions ...
as the acidic character is measured by it's ability to lose H.
thus it was difficult to compare the acidity...based on the concentration method and hence another method was introduced.
PH= -log [H+]
this method was easier becoz u can say just numbers for PH and so relative acidity can be calculated easily...
(think u can say the ph of H2O is 7 rather than saying it in terms of concentration.)

Answer 6

In the word pH p stands for potenz(power) and H stands for hydrogen.This scale determines the strength of an acid or an alkali.

Answer 7

the little "p" usually denotes -log (base10)

so pH is -log[H]

ie. the negative log (in base 10) of the concentration of H+ ions

It is a measure of the acidity or alkalinity of a substance. The more acid it is, the greater the concentration of H+ and the lower the pH

See the wiki page

Answer 8

ph is a scale of to determine acidity of an acid or basicity of a base.
ph= minus(log (of H ion concn)

it is abbreviated from potential of hydrogen

Answer 9

pH is a measure of the acidity or alkalinity of a solution. Solutions with a pH less than seven are considered acidic, while those with a pH greater than seven are considered basic (alkaline). pH 7 is considered neutral because it is the accepted pH of pure water at 25 °C, although, due to the self-ionization of water, this is not completely accurate. pH is formally dependent upon the activity of hydrogen[1] ions (H+),[2] but for very pure dilute solutions, the molarity may be used as a substitute with some sacrifice of accuracy.[3] Because pH is dependent on activity, a property which cannot be measured easily or predicted theoretically, it is difficult to determine an accurate value for the pH of a solution. The pH reading of a solution is usually obtained by comparing unknown solutions to those of known pH, and there are several ways of doing this.

pH is defined[6] operationally as follows. For a solution X, first measure the electromotive force EX of the galvanic cell

reference electrode | concentrated solution of KCl | solution X | H2 | Pt
and then also measure the electromotive force ES of a galvanic cell that differs from the above one only by the replacement of the solution X of unknown pH, pH(X), by a solution S of a known standard pH, pH(S). The pH of X is then

pH(X) = pH(S) + (ES − EX) F / (RT ln 10)
where

F is the Faraday constant;
R is the molar gas constant;
T is the thermodynamic temperature.
Defined this way, pH is a quantity of dimension 1, that is it has no unit. Values pH(S) for a range of standard solutions S, along with further details, are given in the relevant IUPAC recommendation[7].

pH has no fundamental meaning, its official definition is a practical one. However in the restricted range of dilute aqueous solutions having amount-of-substance concentrations less than 0.1 mol/L, and being neither strongly alkaline nor strongly acidic (2 < pH < 12), the definition is such that

pH = −log10[c(H+) y1 / (1 mol/L)] ± 0.02
where c(H+) denotes the amount-of-substance concentration of hydrogen ion H+ and y1 denotes the activity coefficient of a typical uni-univalent electrolyte in the solution.


[edit] Explanation
In simpler terms, the number arises from a measure of the activity of hydrogen ions in the solution. The pH scale is a reverse logarithmic representation of relative hydrogen proton (H+) concentration. Unlike linear scales that progress in a smooth, incremental manner, a shift in value on the pH scale represents a tenfold difference in H+ concentration. For example, a shift in pH from 2 to 3 represents a 10-fold decrease in H+ concentration, and a shift from 2 to 4 represents a one-hundred (10 × 10)-fold decrease in H+ concentration. The formula for calculating pH is:


Where αH+ denotes the activity of H+ ions, and is dimensionless. In solutions that contain other ions, activity and concentration are not the same. The activity is an effective concentration of hydrogen ions, rather than the true concentration; it accounts for the fact that other ions surrounding the hydrogen ions will shield them and affect their ability to participate in chemical reactions. These other ions effectively change the hydrogen ion concentration in any process that involves H+.

In dilute solutions (such as tap water), the activity is approximately equal to the numeric value of the concentration of the H+ ion, denoted as [H+] (or more accurately written, [H3O+]), measured in moles per litre (also known as molarity). Therefore, it is often convenient to define pH as:


For both definitions, log10 denotes the base-10 logarithm, therefore pH defines a logarithmic scale of acidity. For example, if one makes a lemonade with a H+ concentration of 0.0050 moles per litre, its pH would be:


A solution of pH = 8.2 will have an [H+] concentration of 10−8.2 mol/L, or about 6.31 × 10−9 mol/L. Thus, its hydrogen activity αH+ is around 6.31 × 10−9. A solution with an [H+] concentration of 4.5 × 10−4 mol/L will have a pH value of 3.35.

In solution at 25 °C, a pH of 7 indicates neutrality (i.e. the pH of pure water) because water naturally dissociates into H+ and OH− ions with equal concentrations of 1×10−7 mol/L. A lower pH value (for example pH 3) indicates increasing strength of acidity, and a higher pH value (for example pH 11) indicates increasing strength of basicity. Note, however, that pure water, when exposed to the atmosphere, will take in carbon dioxide, some of which reacts with water to form carbonic acid and H+, thereby lowering the pH to about 5.7.

Neutral pH at 25 °C is not exactly 7. pH is an experimental value, so it has an associated error. Since the dissociation constant of water is (1.011 ± 0.005) × 10−14, pH of water at 25 °C would be 6.998 ± 0.001. The value is consistent, however, with neutral pH being 7.00 to two significant figures, which is near enough for most people to assume that it is exactly 7. The pH of water gets smaller with higher temperatures. For example, at 50 °C, pH of water is 6.55 ± 0.01. This means that a diluted solution is neutral at 50 °C when its pH is around 6.55 and that a pH of 7.00 is basic.

Most substances have a pH in the range 0 to 14, although extremely acidic or extremely basic substances may have pH less than 0 or greater than 14. An example is acid mine runoff, with a pH = –3.6. Note that this does not translate to a molar concentration of 3981 M; such high activity values are the result of the extremely high value of the activity coefficient while concentrations are within a "reasonable" range [8]. E.g. a 7.622 molal H2SO4 solution has a pH = -3.13, hydrogen activity αH+ around 1350 and activity coefficient γH+ = 165.4 when using the MacInnes convention for scaling Pitzer single ion activity coefficient [8].

Arbitrarily, the pH is − log10([H + ]). Therefore,

pH = − log10[H + ]
or, by substitution,

.
The "pH" of any other substance may also be found (e.g. the potential of silver ions, or pAg+) by deriving a similar equation using the same process. These other equations for potentials will not be the same, however, as the number of moles of electrons transferred (n) will differ for the different reactions.

Full Form :
The name, pH, has been purported to come from a variety of places including: pondus hydrogenii (Latin), potentiel hydrogène (French), and potential of hydrogen (English). However pH is actually a shorthand for its mathematical approximation: in chemistry a small p is used in place of writing − log10 and the H should more correctly be [H+], standing for concentration of hydrogen ions.

Answer 10

a Hydrogen ion concentration in a liquid.