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

Body composition assessment methods - underwater weighing, Define Body Comp...

Define Body Composition Assessment Methods - Underwater Weighing? Underwater weighing or hydrostatic weighing is one of the most common body composition methods used in laborat

Describe primitive anaerobic eukaryotic cells, Q. How can the hypothesis th...

Q. How can the hypothesis that asserts that chloroplasts as well as mitochondria were primitive prokaryotes that related in mutualism with primitive anaerobic eukaryotic cells be c

Evolutionary Biology-Genetic Drift, Imagine a population evolving by geneti...

Imagine a population evolving by genetic drift in which the frequency of allele K is 0.65. What is the probability that at some point in the future allele K will drift to a frequen

Explain cell signaling, In multicellular organisms there is a requirement f...

In multicellular organisms there is a requirement for the cells to communicate with one another in order to coordinate their metabolism and growth.  The principal way by  that  cel

What are atherosclerosis, Atherosclerosis, the most common part of hardenin...

Atherosclerosis, the most common part of hardening of the arteries, is characterized by the presence of cholesterol-rich arterial thickenings (atheromas).  This progressive  diseas

In which parts of the circulatory system are there valves, In which parts o...

In which parts of the circulatory system are there valves? There are valves in the heart (between each atrium and ventricle, in the aorta and pulmonary artery), in some of the

Mention the role o ribosome in peptide, Mention the role o ribosome's in pe...

Mention the role o ribosome's in peptide -bond formation .How does ATP facilitate it? a) Of springs derived by asexual reproduction are known as clones. Justify giving two R

Discuss the biological importance of imidazole, Discuss the biological impo...

Discuss the biological importance of Imidazole. Bring in examples of biomolecules that contain this group. Please be as thorough as possible.

What is cytokinesis in cell reproduction, what is Cytokinesis in cell repro...

what is Cytokinesis in cell reproduction? Cytokinesis: Mitosis is usually followed by cytokinesis, the division of the cytoplasm and cell membrane. Cellular organelles are no

Explain environmental resistance and the population growth, What is the rel...

What is the relationship among environmental resistance and the population growth according to the biotic potential curve and the real population growth curve? The difference

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