Acid is a substance which produces hydrogen ions as the only positive ions when it is dissolved in water.
Acids are classified as weak or strong.
Strong acids are man-made and very corrosive.
Examples: Hydrochloric Acid, Nitric Acid, Sulfuric Acid
Weak acids are man-made and very corrosive.
Example: Acetic Acid, Tartaric Acid, Citric Acid.
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The strength of an acid depends on its degree of dissociation in water to produce hydrogen ions.
A Strong Acid is one that ionises completely in water to produce hydrogen ions.
There are no molecules left.
The solution contains a high concentration of ions: good electrical conductor.
A Weak Acid is one that ionises partially in water to produce a few hydrogen ions.
Most of the acid molecules remain as molecules.
The solution contains a low concentration of ions: poor electrical conductor.
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An acid, when dissolved in water, forms a colourless solution.
Solutions of acids have the following properties:
- Sour taste
- Change the colour of indicators(e.g turn blue litmus paper red)
- Contain hydrogen ions and conduct electricity
- React with metals, carbonates and bases
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Reaction with metals:
Acids react with metals to produce a salt and hydrogen.
Reactions with carbonates:
Acids react with carbonate to produce a salt, carbon dioxide and water.
Reactions with bases:
Acids react with bases (metal oxides and metal hydroxides) to produce salt and water.
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pH at which pH indicator changes colour:
METHYL ORANGE:
pH--> 0-4 ---- Red ( Strong Acid)
pH--> 4-14 --- Yellow (Weak acid + Base)
Conclusion: It is only appropriate for testing of Strong Acids.
PHENOLPHTHALEIN:
pH--> 0-9 --- Colourless (Acid + Weak bases)
pH--> 9-14 --- Red (Strong Bases)
Conclusion: It is only apt to use this for the identification of Strong Bases.
LITMUS PAPER:
pH--> 0-6 --- Red (Acids)
pH--> 8-14 --- Blue (Bases)
Conclusion: Just a vague indicator of Acids and Bases not appropriate to test for Strong Acids or Bases.
UNIVERSAL INDICATOR:
The pH Colour change is shown as above.
Conclusion:
Universal Indicator as its name suggest is Universal. It is very versatile in identification of Strong acids, Weak acids, Strong bases and Weak bases. It is widely used because of its versatile identification of Acids and Bases.
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Bases are the oxides or hydroxides of metal that react with an acid to form a salt and water only.
Most bases are insoluble in water.
Bases that dissolve in water are called alkalis.
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An alkali is a metal hydroxide/oxide which is SOLUBLE in water and produces hydroxide ions in water.
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There are different types of oxides:
Acidic oxide: Carbon dioxide, Sulphur dioxide. Nitrogen oxide
Basic oxide: Calcium oxide, Iron(III) oxide, Magnesium oxide
Neutral oxide: Carbon monoxide, nitric oxide, water
Amphoteric oxide: Zinc oxide, Aluminium oxide, Lead (II) oxide, Lead(IV) oxide
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ACIDIC OXIDE is a non-metallic oxide that neutralises a base to form salt and water. It reacts with water slightly to form an acidic solution.
NEUTRAL OXIDE is a non-metallic oxide that shows neither acidic nor basic properties properties. They are in soluble in water and do not react with water.
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BASIC OXIDE is a metallic oxide that neutralises and acid to form salt and water only. If it is soluble in water, it forms an alkali.
AMPHOTERIC OXIDE is a metallic oxide that react with both acid and base to form salt and water. They have both acidic and basic properties.
My thoughts:
I somehow feel that Acidic oxides is the opposite of Basic oxide and Neutral Oxide is the opposite of Amphoteric oxide.
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Strength of an alkali depends on its degree of ionisation in water to produce hydroxide ions.
The properties of alkalis are due to the hydroxides ions.
A strong alkali is one that ionises completely in water to produce hydroxide ions.
There are no molecules left.
The common strong alkalis are sodium hydroxides and potassium hydroxides.
A weak alkali is one that ionises partially in water to produce hydroxide ions.
Most of the alkali molecules remain as molecules.
The common weak alkali is Ammonia.
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Properties of bases:
Bases are the oxides or hydroxides of metal that react with an acid to form a salt and water only.
Most bases are insoluble in water.
Bases that dissolve in water are called alkalis.
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An alkali is a metal hydroxide/oxide which is SOLUBLE in water and produces hydroxide ions in water.
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There are different types of oxides:
Acidic oxide: Carbon dioxide, Sulphur dioxide. Nitrogen oxide
Basic oxide: Calcium oxide, Iron(III) oxide, Magnesium oxide
Neutral oxide: Carbon monoxide, nitric oxide, water
Amphoteric oxide: Zinc oxide, Aluminium oxide, Lead (II) oxide, Lead(IV) oxide
Basically those oxides can be summarised as below.
Elements
-
-
Metal Non-metals
- -
- -
Basic Oxides Acidic Oxides
Amphoteric Oxides Neutral Oxides
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ACIDIC OXIDE is a non-metallic oxide that neutralises a base to form salt and water. It reacts with water slightly to form an acidic solution.
NEUTRAL OXIDE is a non-metallic oxide that shows neither acidic nor basic properties properties. They are in soluble in water and do not react with water.
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BASIC OXIDE is a metallic oxide that neutralises and acid to form salt and water only. If it is soluble in water, it forms an alkali.
AMPHOTERIC OXIDE is a metallic oxide that react with both acid and base to form salt and water. They have both acidic and basic properties.
My thoughts:
I somehow feel that Acidic oxides is the opposite of Basic oxide and Neutral Oxide is the opposite of Amphoteric oxide.
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Strength of an alkali depends on its degree of ionisation in water to produce hydroxide ions.
The properties of alkalis are due to the hydroxides ions.
A strong alkali is one that ionises completely in water to produce hydroxide ions.
There are no molecules left.
The common strong alkalis are sodium hydroxides and potassium hydroxides.
A weak alkali is one that ionises partially in water to produce hydroxide ions.
Most of the alkali molecules remain as molecules.
The common weak alkali is Ammonia.
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Properties of bases:
- Alkalis have a soapy feel and a bitter taste.
- Alkalis can change the colour of indicators(e.g red litmus paper turns blue)
- Bases can react with acids to form salt and water only----------Neutralisation.
- Bases can react with Ammonium salts to form Salt, Ammonia and Water.
- Alkalis can react with a solution of one metal salt to give metal hydroxide and another metal salt.
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Chapter 3.2: Equation Writing
MY THOUGHTS:
This topic is rather easy.
The most important thing is to grab the concept of balancing an equation.
You must make sure that there an equal number of atoms of each element on each side of the equation.
Note: Coefficients in front of a formula unit multiply that entire formula unit.
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MY THOUGHTS:
This topic is rather easy.
The most important thing is to grab the concept of balancing an equation.
You must make sure that there an equal number of atoms of each element on each side of the equation.
Note: Coefficients in front of a formula unit multiply that entire formula unit.
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