Write the chemical properties of acids or metals with equations as examples.
Answers
Answer:
Acids change the colour of litmus from blue to red.
They convert the colour of Methyl Orange from Orange/Yellow to Pink.
Acids turn the pink colour of Phenolphthalein to colourless.
Acids can conduct electricity.
Some Acids are highly corrosive in nature which means that they corrode or rust metals.
Acids tend to evolve hydrogen gas whilst reacting with an active metal such as Zn, Mg, etc.
They produce H+ ions when mixed with water.
Acids lose their acidity when mixed with a base.
When equal amounts of acid and base are combined the process of neutralization occurs and salt and water is formed,
The pH value of acid is from 0-6. Learn the concept of pH value here.
Acids are sour in taste.
Acids react with carbonates and hydrogen carbonates to form a salt, water, and carbon dioxide gas.
Extremely active metals such as Potassium (K), Calcium (Ca), Sodium (Na), etc tend to explode when combined with acids.
Weak Acids like Carbonic Acid doesn’t act with any metal at all.
Nitric Acids doesn’t usually exhibit acidic properties, it exhibits oxidizing properties instead.
Metals that generally react with dilute acid to form salt and hydrogen are the metals which lie above hydrogen in the metal activity series.
Acids form a salt, water and sulphur dioxide while reacting with sulphites and bisulphites.
Acids and metal sulphides form salt and hydrogen sulphide.
They are classified on the basis of their sources, strength, concentration, the presence of oxygen and its basicity.
The different types of acids are organic acids, mineral acids, strong acids, weak acids, concentrated acids, dilute acids, Oxy-acids, Hydracids, monobasic acids, dibasic acids, and tribasic acids.
Answer:
What are Acids and Bases?
Acids are chemical substances which are characterized by a sour taste in an aqueous medium. They have the tendency to turn blue litmus red. On the other hand, bases are chemical substances which are characterized by a bitter taste and are slippery to the touch. Some bases are soluble in water while others are not.
Water soluble bases are known as alkalis. They have the tendency to turn red litmus blue. Acids and bases react with a wide range of chemical compounds to form salts. Some chemical reactions of acids and bases are:
Acids And Bases
Physical Properties of Acids and Bases
The physical properties of acids and bases are listed in the table below.
Properties Acids Bases
Colour Mineral acids are colourless liquids but sometimes sulphuric acid becomes yellow due to impurities. Some organic acids are white coloured solids.
Examples: benzoic acid
Bases are colourless except the hydroxides of iron and copper.
Taste Sour Bitter
Touch – Slippery
Solubility Soluble in water Some bases are soluble in water.
Physical Properties of Acid
The word “acid” comes from the Latin word for sour. This distinguishable property helps identify acids from other compounds such as salt and bases. Many acids can be hazardous if ingested and shouldn’t be tasted.
Once the acid binds to the base, it becomes a neutral substance. Often this reaction can lead to water and salt. This is often seen when strong acids react with strong bases.
The acids are driving electricity. Outside this, the batteries are used to produce electricity. The acid that conducts electricity strongly is a strong acid, and the acid that conducts electricity weakly is a weak acid.
Chemical Properties of Acid and Bases
1. Reactions of Acids and Bases with Metals
When a metal reacts with an acid, it generally displaces hydrogen from the acids. This leads to the evolution of hydrogen gas. The metals combine with remaining part of acids to form a salt. For example reaction of sulphuric acid with zinc.
H2SO4 + Zn → ZnSO4 + H2
Alkalis (bases that are soluble in water) react with the metal to produce salt and hydrogen gas. For example reaction of zinc with sodium hydroxide.
2 NaOH + Zn → Na2ZnO2 + H2
2. The Reaction of Metal Carbonates/Metal Bicarbonates with Acids
Metal carbonates/metal bicarbonates react with acids to produce salt, carbon dioxide and water. For example the reaction of sodium carbonate/sodium bicarbonate with hydrochloric acid.
Na2CO3 + HCl (aq) → 2NaCl (aq) + H2O(l) + CO2
3. The Reaction of Metal Oxide with Acids
Metal oxides react with acids to produce salt and water. For example reaction of copper oxide and dilute hydrochloric acid.
CuO + 2HCl → CuCl2 + H2
4. The Reaction of Non-metal Oxide with Bases
Non-metal oxides react with bases to produce salt and water. For example the reaction of carbon dioxide and lime water (calcium hydroxide)
CO2 + Ca (OH)2 → CaCO3 + H2O
5. The Reaction between Acids and Bases
Acids react with bases to produce salt and water. The reaction between acids and bases to give salts is known as neutralization reactions. For example the reaction of sodium hydroxide with hydrochloric acid.
NaOH + HCl → NaCl + H2O
Neutralization of Acid and Base
The reaction between an acid and a base invariably gives salt and water and is called neutralization. In a neutralization reaction, one H+ ion of acid is neutralized by one OH- ion is base. When all the H+ ions in the acidic solution are neutralized by the same number of OH- ions of basic solution, it is called complete neutralization. The relative amounts of acid and base required for complete neutralization depends upon the total number of H+ and OH- ions produced by the respective acid and base.
Comparative Study of Properties of Acids and Bases
A comparative study of properties of acids and bases is given below in table.
Corrosive action on skin: All acids and some alkalies show corrosive action on skin as they form painful blisters when they come in contact with skin. H2SO4 absorbs water from skin tissues. HNO3 reacts with skin proteins to form a pulp like mass. NaOH and KOH are called caustic soda and caustic potash, respectively due to their causticizing action on skin.
Reactions taking place between acids and bases: All acids react with alkalis (metal hydroxides) to form salt and water. The reaction of an acid with a base to form salt and water as the products is called neutralization. 2KOH + H2SO4 → K2SO4 + 2H2O
Ca(OH)2 + 2HNO3 → Ca(NO3)2 + 2H2O