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

Explain pasteurization, Explain Pasteurization The act or process of h...

Explain Pasteurization The act or process of heating a beverage or other food, to a specific temperature for a specific period of time in order to kill microorganisms that cou

Explain the nutritional and functional role of potassium, Minerals :- Potas...

Minerals :- Potassium Food Source      Fruits, vegetables, meats Nutritional Functional role Essential nutrient: Deficiency is rare. Salt substitute: KCl may be

State the method of recombination or crossing-over, Which of the following ...

Which of the following statement is false regarding the method of recombination or crossing-over? A. Crossing-over takes place during prophase I of meiosis B. Recombination

Conduction system - heart, In this unit, you have learnt that heart is a mu...

In this unit, you have learnt that heart is a muscular organ situated in thorax covering with pericardium and consist of four chambers i.e. right atrium, left atrium, right ventric

Slow walking or crawling, Slow walking or Crawling This type of locom...

Slow walking or Crawling This type of locomotion is seen while the animal moves on the substratum. It involves a metachronal rhythm of action in the parapodia. Each fifth or

Can you explain balloon valvuloplasty, Q. Can you explain Balloon Valvulopl...

Q. Can you explain Balloon Valvuloplasty? Whenever feasible valvuloplasty is the treatment modality of choice. One has to make sure that the valve is suitable and expertise to

Discuss the biological concepts of the migration, The bar-tailed godwit, Li...

The bar-tailed godwit, Limosa lapponica baueri, or kuaka, is a wading shorebird seen on marshy estuaries and wetlands during the New Zealand summer. Populations of this species emb

Amniocentesis, Amniocentesis is a way of prenatal testing in which the amn...

Amniocentesis is a way of prenatal testing in which the amniotic fluid is withdrawn from the uterus by the help of a needle. The fluid and the fetal cells it contains are analyzed

Which are the respiratory muscles in mammals, Q. Which are the respiratory ...

Q. Which are the respiratory muscles in mammals? In mammals the muscles that participate in the breathing process are the diaphragm and the intercostal muscles, in respiratory

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