Acids And Bases

Question 1

Define an acid. Give an example.

Answer 1

A complex compound which is consisted of one Hydrogen atom or several Hydrogen atoms and one acid radical, and produces H+ ions in aqueous solution. Ex:

• Hydrochloric acid : HCl
• Nitric acid: HNO3
• Sulfuric acid: H2SO4

Question 2

Define a base. Give an example.

Answer 2

A complex compound which is consisted of one metal atom and one or several hydroxyl groups and produces OH- ions in aqueous solution. Only one base does not contain a metal atom: NH4OH, Ex:

• Sodium hydroxide: NaOH
• Potassium hydroxide: KOH
• Barium hydroxide: Ba(OH)2

Question 3

Define a strong acid and explain your answer with examples.

Answer 3

A strong acid is completely ionized into its ions in aqueous solution.
Example:
-Hydrochloric acid: HCl

Question 4

Define a weak acid and explain your answer with examples.

Answer 4

A weak acid is only slightly ionized into its ions in aqueous solution.
Example:
- Carbonic acid: H2CO3
- Ethanoic acid: CH3OOH

Question 5

Define a strong base and explain your answer with examples.

Answer 5

A strong base is completely ionized into its ions in aqueous solution.
Examples:
-Sodium hydroxide: NaOH
-Potassium hydroxide: KOH

Question 6

Define a weak base and explain your answer with examples.

Answer 6

A weak base is slightly ionized into its ions in aqueous solution.
Examples:
-Ammonia: NH3

Question 7

How can you differentiate the strong acid and the concentrated acid. Explain your answer with examples in each case.

Answer 7

Strong acid = comp. Ion. In aqueous solution.
Conc. acid = not diluted.
Measure of available ions dissolved in the soluvent, meaning more mol/l.

Question 8

Describe the reactions between an acid and a metal oxide. You have to balance all the reactions.

Answer 8

Acid + Metal oxide= salt + water

• H2SO4 + CuO = CuSO4 + H2O

Question 9

Describe the reactions between a base and a non-metal oxide. You have to balance all the reactions.

Answer 9

Base + Non-Metal oxide = Salt + Water

• Ca(OH)2 * CO2= CaCO2 + H20

Question 10

Describe the reactions between an acid and a salt. You have to balance all the reactions.

Answer 10

Acid + Salt = New acid + New salt

- H2S04 + BaCl2 = 2HCL+ BaSO4

Question 11

Describe the reactions between a base and a salt. You have to balance all the reactions.

Answer 11

Base + Salt = New Base + New Salt.

• 2NaOH+ CuSO4 = Cu(OH)2 + NaSO4

Question 12

Describe the neutralization reaction. Why is this reaction called neutralization reaction? What are the products of this reaction You have to balance all the reactions.

Answer 12

Acid + Base = Salt + Water.

• H2SO4 + Ca(OH)2 = CaSO4 + H2O
• KOH + HNO3 = KNO3 +H2O
• The product of the reaction is neutral, the pH becomes 7.

Question 13

What are the products if you heat an acid or a base? Give examples in each case.

Answer 13

A: Heating of an acids produces non- metal oxide and water.
- H2SO= SO2 + H2O

B: Heating of a base produces metal oxide and water.
- Cu(OH)2 = CuO2+ H2O.

Question 14

Describe a reaction between an acid and a metal. You have to balance the reaction.

Answer 14

Acid + Some Metals = Salt + Hydrogen gas.

Mg + 2Hcl = MgCl2 + H2↑.

Question 15

a) Give the definition of pH. Give examples.

Answer 15

• pH: Power of Hydrogen
• pH is defined as being equal to minus the logarithm to the base ten of the hydrogen ion concentration.
• Example: [H+] = 10^-5,5 mol/l
  pH= -lg10^-5,5 = -(-5,5) = 5,5.

Question 16

b) Calculate the pH, if the concentration of H+ ion is 10^-6,8 mol/l.

Answer 16

[H+] = 10^-6,8 mol/l

pH= -lg10^-6,8=

-(-6,8) = 6,8.

Question 17

c) Calculate the pH, if the concentration of H+ ion is 3-6 mol/l.

Answer 17

[H+] = 3^-6 mol/l.

= 10^(lg3^-6)= 10^-2,8=

pH= -lg10^-2,8= -(-2,8)= 2,8.

Question 18

Give the definition of a buffer solution. Give an example.

Answer 18

A solution which resists changes in pH when a small amounts of acid or alkali are added to it.
- Ex. Blood.

Question 19

Acid radicals:

Answer 19

NO3
SO3
SO4
Cl
CO3
PO3
PO4
OH