Explain acid and bases, Biology

Assignment Help:

Explain acid and bases?

Acids and Bases :  Some aqueous solutions, however, such as HCl, form an excess of hydrogen ions [ H+ ] and are called acids. Others, such as NaOH, form an excess of hydroxide ions [OH- ], and are called bases. Basic solutions are said to be alkaline.

Acids and bases are classified as either strong or weak, depending upon whether they are partially or fully ionized in solution. Weak acids, such as vinegar, have a sour taste. Weak bases taste bitter and feel soapy and slippery.

The pH Scale

The pH scale is a measure of the acidity of a solution. It is calculated from the concentration of the hydrogen H+ or hydronium ions H3O+ as follows:

pH = - log [H+] = - log [H3O+]

The equilibrium constant of water (Kw) is defined as follows:

Kw = [H3O+] [OH-] = 1.0 x 10-14

A shorthand way to write the same information is

pH + pOH = 14

The pH of pure water and neutral solutions is 7; acidic solution values are less than 7. The pH values of alkaline solutions (bases) measure more than 7. Note that the pH scale is logarithmic, so that a pH of 4 is 100 times more acidic than a pH of 6. The pH in animal digestive tracts is controlled by secretion of certain glands, and varies from quite acidic, about 2 in the stomach, to somewhat alkaline in the intestines.

Certain dyes, such as phenolphthalein, can be used to give an approximate indication of pH. Specialized meters with probes that are dipped into a solution measure pH very accurately.

Salts and Buffers

Salts are formed by the reaction of acids and bases in water. They may be neutral, acidic or basic, depending upon the pH of their solutions.

Acid +base → salt +water

Because various chemical reactions that occur in living organisms proceed more readily at different pH levels, specialized tissues produce chemical substances called buffers. Buffers dissociate in aqueous solutions and combine with excess H+ or OH - to maintain a constant pH. Buffers are usually weak acids or weak bases, or salts of weak acids or weak bases.

An example of a buffer is carbonic acid H2 CO3 and its bicarbonate ion (HCO3 -), present in red blood cells:

1013_acidic basic.png


Related Discussions:- Explain acid and bases

Describe the phylum chordata in animal kingdom, Describe the Phylum Chordat...

Describe the Phylum Chordata in animal kingdom? This is the other group of animals along with the Echinodermata whose anus develops prior to the mouth's development in the embr

Explain about the chytridiomycota - fungi, Explain about the Chytridiomycot...

Explain about the Chytridiomycota - Fungi Chytridiomycota - Look at the Figure, which illustrates chytridiomycota. These are the simplest among true fungi and are commonly call

Deterimne when lysosomic enzymes play a fundamental role, What are some bio...

What are some biological examples in which lysosomic enzymes play a fundamental role? The remodelation of the osseous tissue, the function of acrosomes in sperm cells and the e

Explain the solubility in water of dietary fibre, Explain the Solubility in...

Explain the Solubility in Water of dietary fibre? Fibres that dissolve in hot water are soluble and those that do not, are insoluble. Several structural features affect solubil

The warmest parts of the body?, What are likely to be (a) the coldest, (b) ...

What are likely to be (a) the coldest, (b) the warmest parts of the body? The extremities of the body (hands and fingers, feet and toes, ears and nose) are likely to be the col

Explain adverse effects of atazanavir, Explain Adverse effects of Atazanavi...

Explain Adverse effects of Atazanavir  Atazanavir causes indirect hyperbilirubinemia. It has had no adverse effects on lipid profiles, but the drug's long-term effects are unkn

Temperate rain forests - ecosystem, Temperate rain forests - Ecosystem ...

Temperate rain forests - Ecosystem The temperate rain Forests are colder than any other rain forest and exhibit a marked seasonality with regard to temperature and rainfall. R

Describe thg epa current registration process?, How will the plant-incorpor...

How will the plant-incorporated protectants rules change EPA's current registration process? The rules clarify which plant-incorporated protectants are needed to be evaluated u

Is neuron b in the frog central nervous system, IS Neuron B in the frog cen...

IS Neuron B in the frog central nervous system Consider Neuron B in the frog central nervous system whose plasma membrane has a previously unknown channel that is selectly cond

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd