explain in detail the role of pH in our daily life.

 pH in plants and animals:

Our body works within the pH range of 7.0 to 7.8. Living organisms can

survive only in a narrow range of pH change. When pH of rain water is

less than 5.6, it is called acid rain. When acid rain flows into the rivers, it
 
lowers the pH of the river water. The survival of aquatic life in such rivers
 
becomes difficult.
 
pH in our digestive system:
 
It is very interesting to note that our stomach produces hydrochloric
 
acid. It helps in the digestion of food without harming the stomach.
 
During indigestion the stomach produces too much acid and this causes
 
pain and irritation. To get rid of this pain, people use bases called
 
antacids. One such remedy must have been suggested by you at the
 
beginning of this Chapter. These antacids neutralise the excess acid.
 
Magnesium hydroxide (Milk of magnesia), a mild base, is often used for
 
this purpose.
 
pH in our tooth!
 
Tooth decay starts when the pH of the mouth is lower than 5.5. Tooth
 
enamel, made up of calcium phosphate is the hardest substance in the
 
body. It does not dissolve in water, but is corroded when the pH in the
 
mouth is below 5.5. Bacteria present in the mouth produce acids by
 
degradation of sugar and food particles remaining in the mouth after
 
eating. The best way to prevent this is to clean the mouth after eating
 
food. Using toothpastes, which are generally basic, for cleaning the teeth
 
can neutralise the excess acid and prevent tooth decay.
 
Self defence by animals and plants through chemical warfare
 
 
Bee-sting leaves an acid
 
which causes pain and irritation. Use of a mild base like baking soda
 
on the stung area gives relief. Stinging hair of nettle leaves inject
 
methanoic acid causing burning pain.

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In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at 25 °C (77 °F). Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. pH measurements are important in medicine, biology, chemistry, agriculture, forestry, food science, environmental science, oceanography, civil engineering and many other applications.

In a solution pH approximates but is not equal to p[H], the negative logarithm (base 10) of the molar concentration of dissolved hydronium ions (H3O+); a low pH indicates a high concentration of hydronium ions, while a high pH indicates a low concentration. This negative of the logarithm matches the number of places behind the decimal point, so, for example, 0.1 molar hydrochloric acid should be near pH 1 and 0.0001 molar HCl should be near pH 4 (the base 10 logarithms of 0.1 and 0.0001 being −1, and −4, respectively). Pure (de-ionized) water is neutral, and can be considered either a very weak acid or a very weak base (center of the 0 to 14 pH scale), giving it a pH of 7 (at 25 °C (77 °F)), or 0.0000001 M H+. For an aqueous solution to have a higher pH, a base must be dissolved in it, which binds away many of these rare hydrogen ions. Hydrogen ions in water can be written simply as H+ or as hydronium (H3O+) or higher species (e.g., H9O4+) to account for solvation, but all describe the same entity. Most of the Earth's freshwater bodies surface are slightly acidic due to the abundance and absorption of carbon dioxide in fact, for millennia in the past, most fresh water bodies have long existed at a slightly acidic pH level.

However, pH is not precisely p[H], but takes into account an activity factor. This represents the tendency of hydrogen ions to interact with other components of the solution, which affects among other things the electrical potential read using a pH meter. As a result, pH can be affected by the ionic strength of a solution – for example, the pH of a 0.05 M potassium hydrogen phthalate solution can vary by as much as 0.5 pH units as a function of added potassium chloride, even though the added salt is neither acidic nor basic.

Hydrogen ion activity coefficients cannot be measured directly by any thermodynamically sound method, so they are based on theoretical calculations. Therefore, the pH scale is defined in practice as traceable to a set of standard solutions whose pH is established by international agreement.

Primary pH standard values are determined by the Harned cell, a hydrogen gas electrode, using the Bates–Guggenheim Convention.

pH in its usual meaning is a measure of acidity of (dilute) aqueous solutions only.

Recently the concept of "Unified pH scale" has been developed on the basis of the absolute chemical potential of the proton. This concept proposes the "Unified pH" as a measure of acidity that is applicable to any medium: liquids, gases and even solids.

  • -14

The role is that when we get a csting of a bee or an ant we use a mild base to neutralize the acid injested in us.

Another example is that we eat a lot of chocolates and drink a lot of coffee which leads to a low pH in our mouth on our teeth as coffees's pH is less than 5.5 and our teeth can only tolerate 5.5 pH which causes cavity gap in the teeth which further may even lead to a complete tooth decay which is why after eating something we brush with toothpaste which is slightly basic and which neutralizes our pH in the mouth

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stomach secretes hcl to kill bacteria and digest food without harming the stomach. during indigestion stomach produces too much acid and causes pain and irritaion. to get rid of this we use bases called antacids.eg: milk of magnesia.

plants require a specific range of ph for their healty growth.

human body works in ph range of 7.0 to 7.8

when ph of rainwater is less than 5.6, it is acid rain.it damages aquatic life , monuments.....

lower ph because of sweet and sour food can cause toooth decay.ph of mouth should be more than 5.5.to prevent this we use tooth pastes that are basic in nature

certain animals like bee and plants like neetle secrete highly acidic substance for self defence.use of a mild base like baking soda gives relief.

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