Question

PRE-LABORATORY QUESTIONS 1. Why is it unwise to mix haphazardly household chemicals or other chemicals? Household chemicals may appear Combined, can produce explosions or other to reactions. 2. What test could you perform to detect the presence of H on? Write a reaction and explain what it is expected to happen. 3. What test could you perform to detect the presence of Colon? Write a reaction and explain what it is expected to happen, 4. What test could you perform to detect the presence of Orion? Write a reaction and explain what it is expected to happen. lon? Write a reaction and explain what 5. What test could you perform to detect the presence of SO it is expected to happen. 6. What test could you perform to detect the presence of rion? 7. What test could you perform to detect the presence of Aglon? Write a reaction and explain what it is expected to happen. Send a chat

Answer 1

Test for NH₄⁺:

Procedure:To the salt solution,Concentrated NaOH solution is added.

Observation:Evolution of gas with a pungent smell of Ammonia which makes Nessler's reagent brown in colour.

Interpretation: NH₄⁺ + OH^- = NH₃ +H₂O

NH₃ + K₂[HgI₄] + KOH  -----> NH₂--Hg--O--HgI{brown} + KI +H₂O

Test for Carbonate(CO₃^2-):

Procedure: To the test solution,Concentrated HCl solution is added.

Observation: Bubbling of a gas which makes lime water milky.

Interpretation:

CO₃^2-+ H⁺ = CO₂

CO₂ + Ca(OH)₂ = Ca(CO₃){Makes the solution milky) +H₂O

Test for Chloride(Cl^-):

Procedure:To the test solution, a few drops of silver nitrate solution was added.

Observation: A white curdy precipitate is formed which is soluble in excess ammoniacal solution.

Interpretation:

Cl^- + AgNO₃ = AgCl(white precipitate) + NO₃^-

AgCl + NH₄OH = [Ag(NH₃)₂]⁺ {soluble}

Test for SO₄^2-:

Procedure:To the test solution, a few drops of barium chloride solution are added.

Observation: A white precipitate is observed.

Interpretation: SO₄^2-+ BaCl₂= BaSO4(White precipitate) + Cl^-

Test for I^-:

Procedure: To the test solution, a few drops of silver nitrate solution are added.

Observation: A yellow precipitate is observed which is insoluble in excess ammoniacal solution.

Interpretation: I^- + AgNO₃ = AgI( yellow precipitate) +NO₃^-

AgI + NH₄OH -----> No reaction

Test for Ag⁺:

Procedure: To the test solution, about 6(M) Concentrated HCl solution is added.

Observation: A curdy white precipitate appeared which dissolves in excess ammoniacal solution.

Interpretation:

Ag⁺ + Cl^-(from HCl)= AgCl{ curdy white precipitate}

AgCl + NH₄OH = [Ag(NH₃)₂]⁺ {Soluble}