name any two salts that behave like base in water
Answers
Acids have a sour taste.
2. Acids are corrosive.
3. Acids change the color of certain vegetable dyes, such as litmus, from blue to red.
4. Acids lose their acidity when they are combined with alkalies.
The name "acid" comes from the Latin acidus, which means "sour," and refers to the sharp odor and sour taste of many acids.
Examples: Vinegar tastes sour because it is a dilute solution of acetic acid in water. Lemon juice tastes sour because it contains citric acid. Milk turns sour when it spoils because lactic acid is formed, and the unpleasant, sour odor of rotten meat or butter can be attributed to compounds such as butyric acid that form when fat spoils.
In 1661 Boyle summarized the properties of alkalies as follows.
Alkalies feel slippery.
Alkalies change the color of litmus from red to blue.
Alkalies become less alkaline when they are combined with acids.
In essence, Boyle defined alkalies as substances that consume, or neutralize, acids. Acids lose their characteristic sour taste and ability to dissolve metals when they are mixed with alkalies. Alkalies even reverse the change in color that occurs when litmus comes in contact with an acid. Eventually alkalies became known as bases because they serve as the "base" for making certain salts.
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The Arrhenius Definition of Acids and Bases
In 1884 Svante Arrhenius suggested that salts such as NaCl dissociate when they dissolve in water to give particles he called ions.
H2O
NaCl(s) -----> Na+(aq) + Cl-(aq)
Three years later Arrhenius extended this theory by suggesting that acids are neutral compounds that ionize when they dissolve in water to give H+ ions and a corresponding negative ion. According to his theory, hydrogen chloride is an acid because it ionizes when it dissolves in water to give hydrogen (H+) and chloride (Cl-) ions as shown in the figure below.
H2O
HCl(g) -----> H+(aq) + Cl-(aq)
Diagram
Arrhenius argued that bases are neutral compounds that either dissociate or ionize in water to give OH- ions and a positive ion. NaOH is an Arrhenius base because it dissociates in water to give the hydroxide (OH-) and sodium (Na+) ions.
H2O
NaOH(s) -----> Na+(aq) + OH-(aq)
An Arrhenius acid is therefore any substance that ionizes when it dissolves in water to give the H+, or hydrogen, ion.
An Arrhenius base is any substance that gives the OH-, or hydroxide, ion when it dissolves in water.
Arrhenius acids include compounds such as HCl, HCN, and H2SO4 that ionize in water to give the H+ ion. Arrhenius bases include ionic compounds that contain the OH- ion, such as NaOH, KOH, and Ca(OH)2.
This theory explains why acids have similar properties: The characteristic properties of acids result from the presence of the H+ ion generated when an acid dissolves in water. It also explains why acids neutralize bases and vice versa. Acids provide the H+ ion; bases provide the OH- ion; and these ions combine to form water.
H+(aq) + OH-(aq) -----> H2O(l)
The Arrhenius theory has several disadvantages.
It can be applied only to reactions that occur in water because it defines acids and bases in terms of what happens when compounds dissolve in water.
It doesn't explain why some compounds in which hydrogen has an oxidation number of +1 (such as HCl) dissolve in water to give acidic solutions, whereas others (such as CH4) do not.
Only the compounds that contain the OH- ion can be classified as Arrhenius bases. The Arrhenius theory can't explain why other compounds (such as Na2CO3) have the characteristic properties of bases.
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The Role of H+ and OH- Ions In the Chemistry of Aqueous Solutions
Becuase oxygen (EN = 3.44) is much more electronegative than hydrogen (EN = 2.20), the electrons in the H--O bonds in water aren't shared equally by the hydrogen and oxygen atoms. These electrons are drawn toward the oxygen atom in the center of the molecule and away from the hydrogen atoms on either end. As a result, the water molecule is polar. The oxygen atom carries a partial negative charge (delta-), and the hydrogen atoms carry a partial positive charge (delta+).
water molecule diagram
When they dissociate to form ions, water molecules therefore form a positively charged H+ ion and a negatively charged OH- ion.
chemical equation
The opposite reaction can also occur -- H+ ions can combine with OH- ions to form neutral water molecules.
chemical equation
the two salts are :-
KCN, NH4No3
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