Final Practice About Explanation of Acid and Bases

 ACID AND BASES

A. UNDERSTANDING ACID AND BASES

The acidity and alkalinity of a substance depends on the amount of H + (acid) and OH- (base) ions present in the substance and the degree of ionization of the substance. The acidity and alkalinity of a substance is expressed by pH. In the discussion this time, I will explain about the understanding of acid-base. Material Definition of Acid Bases is very necessary as a foundation of knowledge to understand chemistry materials.

The word "acid" comes from the Latin "acidus" which means sour. Acid is a substance (compound) that causes a sour taste in various materials. Bases are substances (compounds) that can act with acids, producing a compound called salt. While the base is the substances that can neutralize the acid. Chemically, acids and bases are opposite each other. Base properties are generally shown from bitter taste and slippery.

B. THEORY OF ACID AND BASES

1. Arrhenius

Arrhenius put forward a theory of Acid Bases. This theory states that acid is a substance that if dissolved in water will produce H + ions in which this H + ion will be the only positive ion in the solution.

Whereas a base is a substance which, when dissolved in water, ionizes to produce OH-ions, and OH-ions will be the only negative ions in solution.

2. Bronsted-Lowry

Other theories put forward are Bronsted-Lowry Theory which says the acid is a compound that can give protons (H +) to other compounds, while the base can receive protons (H +) from other compounds. The acid-base reaction is the reaction of proton transfer from one compound to another.

3. Lewis

The last theory is Lewis theory which states a base is a substance that has one or more free electron pairs which can be applied to another substance to form covalent coordination bonds, whereas acid is a substance that can accept the pair of free electrons.

 C. ACIDS AND BASIC PROPERTIES

1. The properties of acids are:

·         It tastes sour / sour

·         Corrosive or damaging

·         When dissolved in water can produce H + ions or hydrogen ion ions and negatively charged acidic acid ions. When tested with a blue litmus paper indicator it can turn the litmus red. Whereas if tested with a red litmus paper indicator, the litmus paper will not change color. An indicator is a means to indicate a substance whether acidic or basic.

2. Properties of bases are

·         Bitter taste

·         It is caustic or can damage the skin

·         When dissolved in water may produce OH-ions or hydroxyl ions and metal ions or other negatively charged groups. When the OH ion is almost entirely released or its ionisation is perfect, it includes a strong base or is said to have a low acidity and vice versa.

·         When tested with an indicator in the form of a red litmus, it will change the color of the litmus to blue, while with blue litmus paper, it will not change the color of the litmus paper

D. ACID AND BASE INDICATORS

1. Litmus paper 

One of the most commonly used indicators is litmus paper. There are two types of litmus paper: blue litmus paper and red litmus paper.Red litmus paper will change color to blue when exposed to base, but if exposed to acid or neutral substance then will not change color.The blue litmus paper will turn red when exposed to acid, but if exposed to a base or a neutral substance it will not change color.Paper Lakmus can only compare a substance that includes acid or base, then developed again indicator paper.The universal indicator paper is able to show the acidity and alkalinity of a substance.By comparing the color obtained for each substance tested by the standard paper present in the universal indicator, we can determine the acidity of a substance

2. Indicator of the solution

In addition to litmus paper, and universal indicators, there are also several indicator solutions that are often used in laboratory experiments.

Examples The indicator of this solution is methyl red, methyl orange, bromotimol blue, and several other solutions. This indicator works exactly with litmus paper, this solution will give a color change when exposed to acid or base.

3. Natural indicator

In addition to the common indicators found in the Laboratory, there are several plants around which are able to be indicators when the pH changes.

E. ACID AND BALANCE BALANCE

·        Acid-base buffer systems that immediately combine with acids or bases that will then prevent pH changes or excessive hydrogen ion concentrations.

·     If the hydrogen ion concentration changes, the respiratory center in the brain will be stimulated or stimulated to alter the respiratory rate in the lungs, which will result in changes in the rate of carbon dioxide release from the body that will make the hydrogen ion concentration return to normal.

·         Changes in the concentration of hydrogen ions will also cause the kidneys to remove acidic or base urine depending on what compounds excess, thus helping the concentration of hydrogen ions in the body fluids back nomal.

·      This buffer system can work in a fraction of a second to prevent excessive changes in the hydrogen ion concentration. In contrast the respiratory system takes 1-3 minutes to re-adjust the ionhidrogen concentration after a sudden change. Then the kidney, which is the most powerful acid-base component, takes several hours to more than 24 hours to adjust the hydrogen ion concentration.

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