Bases Flashcards
What is a base?
A complex substance that consists of a metal cation and a hydroxyl group (OH)
What are some examples of bases?
NaOH
Ba (OH)2
Fe (OH)2
How do we name bases?
- We write the word hydroxide
- We indicate the name of the second chemical element in the genetive case.
- If the second element has a valency, we indicate it in brackets in compound name.
How are bases classified?
By solubility
How are soluble bases classified?
They’re classified:
Alkali; bases which are soluble in water
Insoluble water: Such as Fe(OH)2 and Cu(OH)2
What are amphoteric bases?
Bases formed by metals with an oxidation state of +3 or +4 and exhibit both acidic and basic properties.
What are the examples of amphoteric bases with a different valency?
Zn (OH)2, Pb (OH)2, Sn (OH)2 and Be (OH)2
How are monoacidic, duo-acidic and tri-acidic compounds distinguished?
According to the number of hydroxyl groups which get replaced by an acid residue.
What are physical properties of bases?
Under normal conditions, they are colorless, non-volatile, crystalline, and often white
Which bases are white?
Lithium Hydroxide (LiOH)
Magnesium (II) hydroxide (Mg (OH)2)
Calcium (II) hydroxide (Ca (OH)2)
Which base is yellow?
Copper (II) Hydroxide (CuOH)
Which base is light purple?
Manganese (II) Hydroxide Mn(OH)
Which base is red brown?
Iron (III) Hydroxide Fe (OH)3
which base is white with a greenish tint?
Iron (II) Hydroxide Fe (OH)2
Which base is light green
Nickel (II) Hydroxide Ni (OH)2
Which base is blue?
Copper (II) Hydroxide Cu (OH)2
How do bases interact with acids and amphoteric oxides?
They form a salt + water
How do bases react with salts?
They form another base and a salt
How do bases react in thermal decomposition?
They form an oxide and water.
How do alkalis react with amphoteric hydroxides?
If solid, a medium salt and water is formed. But if in solution, a complex salt is formed.
How do metals interact with water?
Active metals (metals in G1 and 2, except for Be and Mg) actively interact with water and lead to the formation of alkalis.
Magnesium hydroxide can only be obtained this way when heated.
Eg
2Na + 2H2O = 2NaOH + H2
How do oxides of alkali and alkaline earth metal atoms react with water?
They form an alkali.
Cao + H2O = Ca (OH)2
What is electrolysis?
This is when a constant electric current is conducted through a solution.
What does electrolysis lead to in terms of bases?
It can help us obtain Sodium or Potassium Hydroxide
E.G
KCl + H2O = KOH + H2+ Cl2
How do we obtain insoluble bases?
By reacting an alkali with a salt
E.G
Cu (NO3)2 + 2KOH = CU (OH)2 + 2KNO3
