To Identify The Acidic Radical Present In A Given Salt Sample (s1). | Grade Xi

APPARATUS REQUIRED:

• Test tube
• Test tube stand
• Bunsen burner
• Filter paper
• Dropper
• pH paper
• Sodium hydroxide solution (NaOH)
• Sulfuric acid solution (H2SO4)
• Hydrochloric acid solution (HCl)
• Nitric acid solution (HNO3)
• Sodium carbonate solution (Na2CO3)
• Potassium iodide solution (KI)
• Silver nitrate solution (AgNO3)
• Barium chloride solution (BaCl2)

CHEMICALS REQUIRED:

• Salt sample (S1)
• Distilled water

THEORY:

An acid radical is a negatively charged ion that is formed when an acid loses a hydrogen ion (H+). The acidic radical is responsible for the characteristic properties of the acid, such as its sour taste and its ability to react with bases to form salts.

In this experiment, we will use a series of chemical tests to identify the acidic radical present in a given salt sample. The tests will involve reacting the salt sample with various reagents and observing the resulting reactions.

PROCESS:

1. Preparation of the Salt Solution:

   • Dissolve a small amount of the salt sample in distilled water to form a salt solution.

2. pH Test:

   • Use pH paper to test the pH of the salt solution.
   • If the pH is less than 7, then the salt solution is acidic.
   • If the pH is greater than 7, then the salt solution is basic.
   • If the pH is equal to 7, then the salt solution is neutral.

3. Reaction with Sodium Hydroxide Solution:

   • Add a few drops of sodium hydroxide solution to the salt solution.
   • Observe the reaction.
   • If a precipitate forms, then the acidic radical is a carbonate (CO32-) or a phosphate (PO43-).

4. Reaction with Sulfuric Acid Solution:

   • Add a few drops of sulfuric acid solution to the salt solution.
   • Observe the reaction.
   • If a gas is evolved, then the acidic radical is a carbonate (CO32-) or a sulfide (S2-).

5. Reaction with Hydrochloric Acid Solution:

   • Add a few drops of hydrochloric acid solution to the salt solution.
   • Observe the reaction.
   • If a gas is evolved, then the acidic radical is a carbonate (CO32-).

6. Reaction with Nitric Acid Solution:

   • Add a few drops of nitric acid solution to the salt solution.
   • Observe the reaction.
   • If a gas is evolved, then the acidic radical is a nitrate (NO3-).

7. Reaction with Sodium Carbonate Solution:

   • Add a few drops of sodium carbonate solution to the salt solution.
   • Observe the reaction.
   • If a precipitate forms, then the acidic radical is a calcium (Ca2+) or a magnesium (Mg2+).

8. Reaction with Potassium Iodide Solution:

   • Add a few drops of potassium iodide solution to the salt solution.
   • Observe the reaction.
   • If a precipitate forms, then the acidic radical is a lead (Pb2+) or a mercury (Hg2+).

9. Reaction with Silver Nitrate Solution:

   • Add a few drops of silver nitrate solution to the salt solution.
   • Observe the reaction.
   • If a precipitate forms, then the acidic radical is a chloride (Cl-) or a bromide (Br-).

10. Reaction with Barium Chloride Solution:

    • Add a few drops of barium chloride solution to the salt solution.
    • Observe the reaction.
    • If a precipitate forms, then the acidic radical is a sulfate (SO42-) or a phosphate (PO43-).

OBSERVATIONS:

The observations from the chemical tests are summarized in the table below.

Test	Observation	Acidic Radical
pH Test	pH < 7	Acidic
Reaction with Sodium Hydroxide Solution	Precipitate forms	Carbonate (CO32-) or Phosphate (PO43-)
Reaction with Sulfuric Acid Solution	Gas is evolved	Carbonate (CO32-) or Sulfide (S2-)
Reaction with Hydrochloric Acid Solution	Gas is evolved	Carbonate (CO32-)
Reaction with Nitric Acid Solution	Gas is evolved	Nitrate (NO3-)
Reaction with Sodium Carbonate Solution	Precipitate forms	Calcium (Ca2+) or Magnesium (Mg2+)
Reaction with Potassium Iodide Solution	Precipitate forms	Lead (Pb2+) or Mercury (Hg2+)
Reaction with Silver Nitrate Solution	Precipitate forms	Chloride (Cl-) or Bromide (Br-)
Reaction with Barium Chloride Solution	Precipitate forms	Sulfate (SO42-) or Phosphate (PO43-)

OBSERVATION TABLE:

Salt Sample	pH	Reaction with NaOH	Reaction with H2SO4	Reaction with HCl	Reaction with HNO3	Reaction with Na2CO3	Reaction with KI	Reaction with AgNO3	Reaction with BaCl2	Acidic Radical
S1	4	Precipitate forms	Gas is evolved	Gas is evolved	No reaction	No reaction	No reaction	Precipitate forms	Precipitate forms	Sulfate (SO42-)

CALCULATION:

The calculation of the acidic radical concentration in the salt sample is not required for this experiment.

RESULTS:

The acidic radical present in the given salt sample (S1) is sulfate (SO42-).

PRECAUTIONS:

• Wear gloves and eye protection when performing the chemical tests.
• Handle the chemicals with care.
• Dispose of the chemicals properly.