Acids and Bases

Question 1

Describe the Arrhenius definition of acids and bases

Answer 1

•Acids are substances that increase concentration of H+ ions when dissolved in water •Bases are substances that when dissolved in water, increase the concentration of OH- ions

Question 2

Describe the bronsted lowery concept

Answer 2

•Acids donate protons and bases accept protons •Acids and bases are easily ionised(dissociated)

Question 3

Express the formula for the bronsted lowery concept at equilibrium

Answer 3

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Question 4

What is ka?

Answer 4

•The acid dissociation constant- an equilibrium constant for the dissociation of an acid

Question 5

What is pKa?

Answer 5

•Dissociation constant which is equal to -log10 ka •Value indicates the strength of an acid- the larger the value of pKa, the weaker the acid

Question 6

What determines the strength of an acid or base in water?

Answer 6

•Its ability to donate or accept electrons

Question 7

Describe strong acids

Answer 7

•Belong to group of strong electrolytes • In aqueous solution- almost completely dissociated and resulting anions do not react with water and are not able to bind H+ •Anions of strong acids are weak conjugated bases- do not participate in acid base reactions

Question 8

Describe anions of strong acids

Answer 8

•Are weak conjugated bases- do not participate in acid base reactions •Are spectator ions

Question 9

Describe weak acids

Answer 9

•Belong to weak electrolytes •The weaker the acid, the higher the affinity of anions to H+ and thus a stronger conjugated base •Weak acids include almost all carboxylic and other organic acids

Question 10

Describe medium strength acids

Answer 10

•Acids with pKa of 1-3

Question 11

What is the base dissociation constant?

Answer 11

•A measure of basicity •Is the negative log of Kb

Question 12

Describe strong bases

Answer 12

•Belong to group of strong electrolytes •In water, completely dissociate to ions which do not participate in acid base reactions

Question 13

List examples of strong acids

Answer 13

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Question 14

List examples of strong hydroxides

Answer 14

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Question 15

What is self ionisation of water?

Answer 15

•Chemical reaction in which two water molecules react to produce a hydronium (H30+) and a hydroxide ion (OH)

Question 16

Bronsted-lowery concept for acids and bases. Give an example of a bronsted Lowry base

Answer 16

•NH3 •H20

Question 17

Bronsted-lowery concept for acids and bases. Give an example of a bronsted Lowry acid

Answer 17

•HCL •HNO3

Question 18

Autoionisation of water main concept- formulate the ion product of water and describe which factors it depends on

Answer 18

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Question 19

Give a definition for the power of hydrogen pH, describe the methods for its determination

Answer 19

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Question 20

Give a definition and example of a buffer solution, write the Henderson hasslebalch equation for alkaline buffer solution

Answer 20

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Question 21

Formula for buffer capacity

Answer 21

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