Acid, Base and Salt

Acid, Base and Salt|| Acid || Base || Base|| Salt|| Alkali|| Litmus

Q1. What do you understand by an acid and a base? Give two examples of each.
Ans:
Acid: Acids are those chemical substances which are sour in taste and give hydrogen ions when dissolved in water. For example: Hydrochloric acid (HCL), Suplhuric acid (H₂SO₄ ) etc.
Base: Metallic oxides and hydroxides are called bases. For example: Calcium oxide (CaO), Magnesium oxide (MgO) etc.

Q2. Write any two differences between acid and base.
Ans:
The differences between acid and base are:

Acid	Base
Acid gives H+ ion when it dissolves in water.	Alkali (Base) gives OH- ion when it dissolves in water.
Acids are sour in taste.	Alkalies are bitter in taste.
Acids turn blue litmus paper into red.	Bases turn red litmus paper into blue.
For example: Nitric acid (HNO3), Acetic acid (CH3COOH) etc.	For example: Sodium oxide (Na2O, Potassium oxide (K2O) tec.

Q3. How many types of bases are there? Give with examples.
Ans:
There are two types of bases. They are:

1. Water insoluble bases: for example: HgO, PbO etc.
2. Water soluble bases: for example: Mg(OH)₂, Ca(OH)₂, etc.

Q4. Write the physical properties of acids.
Ans:
The following are the properties of acids:

1. Acids are sour in taste, but the laboratory acids are dangerous to taste.
2. An acid turns blue litmus paper into red.
3. An acid turns methly orange into red.
4. An acid is neutral to phenolpthalein.

Q5. Write are the chemical properties of acids.
Ans:
The following are the chemical properties of acids;

1. An acid reacts with a metal like zinc, Magnesium etc. and forms hydrogen gas.
   Eg: 2HCL + Zn ----------ZnCl₂+ H₂
2. The reaction between an acid and a base results in the formation of salt and water.
   HCl + NaOH ----------NaCl + H₂O
3. An acid when dissolved in water gives off hydrogen ion (H⁺).
   HCL ------------ H⁺ + Cl^-

Q6. Write the physical properties of bases.
Ans:
Physical properties of bases are:

1. A base tastes bitter.
2. The solution of base and water is slippery.
3. A base turns the red litmus into blue.
4. It turns methyl orange into yelow color.
5. It turns phenolpthalein into pink color.

Q7. Write the chemical properties of bases.
Ans:
The following are the chameical properties of bases:

1. The reaction between a base and an acid results int the formation of salt and water.
   2NaOH + H₂SO -----------------Na₂SO₄ + H₂O
2. A base reacts with carbondioxide and forms carbonate.
   2NaOH + CO₂ ------------------- Na₂CO₃ + H₂O

Q8. Write the sources of folowing acids:
Citric acid, Acetic acid, Carbonic acid, Tartaric acid, Formie acid, Ascorbic acid, Lactic acid.
Ans:

Acids	Sources
Citric acid	Lemon, tomato
Acetic acid	Vinegar, Sour pickle
Carbonic acid	Soad water
Tartari acid	Fruits
Formie acid	Secretion through ant-sting.
Ascorbic acid	Sour fruits
Lactic acid	Sour milk

Q9. Write the common properties of acid and base.
Ans:
Acids and bases react with each other giving salts and water.
i.e. HCl + NaOH ----------- NaCL + H₂O

Q10. What happens when acid and base are separately put into water?
Ans:
When acid is put into water, it gives H⁺ ion.
When base is put into water, it gives OH^- ion. 

Q11. What happens when acid is treated with magnessium and zinc metal?
Ans:
When acid is treated with Magnessium and Zinc metal, it gives hydrogen gas.
2HCL + Zn --------------- ZnCl₂ + H₂
H₂SO₄ + Mg ----------------- MgSO₄ + H₂