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

Gonad glands, what are the gonad gland disorders and what do they do

what are the gonad gland disorders and what do they do

What is abscess and gingival biotype, What is Abscess and Gingival Biotype ...

What is Abscess and Gingival Biotype Abscess: Rule out any presence of Periapical or /and Periodontal abscess Gingival Biotype: Thickness of the gingival is an important

Do enzymes act better under acid or basic ph, Do enzymes act better under a...

Do enzymes act better under acid or basic pH? Most enzymes act in pH among 6 and 8, a range that corresponds to the general acidic level of cells and blood. There are enzymes,

How do populations of predators vary in predatism, How do populations of pr...

How do populations of predators and prey vary in predatism? Whenever a predator population enhances at the first moment the prey population tends to decrease. At a second momen

Zoology, what is hydrostatic skeleton?

what is hydrostatic skeleton?

Biotechnology in characterization of animal biodiversity, Use of biotechnol...

Use of biotechnology in characterization of animal biodiversity. Genetic uniqueness of populations is measured by the relative genetic distances of such populations from each o

What conclusion can draw about microorganisms, What conclusion you can draw...

What conclusion you can draw about microorganisms that you saw under microscope from the plaque of your teeth?

Difference between ectoparasite and endoparasite, Q. What is the difference...

Q. What is the difference between ectoparasite and endoparasite? The Ectoparasites are parasites that explore the external surface of the host (like, for instance, mites that p

Evaluating the wound assessment , I will send any further instructions to y...

I will send any further instructions to you. The ist part of the assessment (1-7) that evaluates the chart i have done but it needs to be looked at to see if content okay & gram

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