A student has four beakers on the desktop to identify. The student knows the bea
ID: 928036 • Letter: A
Question
A student has four beakers on the desktop to identify. The student knows the beakers contain the four chemicals listed below. Identify the solution from the description of the experiment. Physical properties Solutions 1, 2, 4, & 5 are clear and colorless solutions. Solution 3 is clear & blue solution. Solution 2 has a strong smell. Solutions 1 & 2 test turn pink litmus paper to blue. Chemical properties When solutions 1 & 2 are mixed, there is no reaction. When solution 1 & 3 are mixed, a blue precipitate forms. when solutions 1 & 4 are mixed, there is no reaction. When 1 & 5 are mixed, a white precipitate forms. Ammonium hydroxide Copper(II) chloride Sodium hydroxide Silver nitrate Potassium chloride What is solution 1? What is solution 2? What is solution 3? What is solution 4? What is solution 5?Explanation / Answer
Solution:
From the question above,
PHYSICAL PROPERTIES:
Solution 3 is a clear and blue solution. All the Cu2+ solutions are clear blue in color. Therefore, Solution 3 is Copper (II) Chloride (CuCl2).
Now, Solution 2 has a strong smell. Out of all the choices, Ammonium Hydroxide (NH4OH) has the most pungent ammonical smell. Therefore, Solution 2 is Ammonium Hydroxide (NH4OH).
Solution 1 and 2 test turn pink litmus paper to blue. Any solution which turns pink litmus into blue means that the solution is “basic” in nature. We already know that Solution 2 is Ammonium Hydroxide (NH4OH). Therefore, Solution 1 has to be Sodium Hydroxide (NaOH).
CHEMICAL PROPERTIES:
When Solution 1 and 2 are mixed, there is no reaction. Previously, we discovered that Solution 1 is Sodium Hydroxide (NaOH) and Solution 2 is Ammonium Hydroxide (NH4OH). So the net reaction will be as follows:
NaOH + NH4OH à Na+ + NH4+ + 2OH-
The two Solutions will remain inert in presence of each other.
When Solution 1 and 3 are mixed, a blue precipitate is formed. From the physical properties we already know that, Solution 1 is Sodium Hydroxide (NaOH) and Solution 2 is Copper (II) Chloride (CuCl2). The net reaction is as follows:
NaOH + CuCl2 à 2NaCl + Cu(OH)2 (blue precipitate)
The blue precipitate so formed is Copper (II) hydroxide (Cu(OH)2).
When Solutions 1 and 4 are mixed, there is no reaction. From the physical properties, we know that Solution 1 is Sodium Hydroxide (NaOH). We have only two choices left, from which Silver nitrate forms a precipitate as soon as it comes in contact with Sodium Hydroxide. Therefore, Solution 4 has to be Potassium Chloride (KCl). The net reaction involved in the reaction is given as:
NaOH + KCl à NaCl + KOH
When 1 and 5 are mixed, a white precipitate is formed. From the physical properties, we know that Solution 1 is Sodium Hydroxide (NaOH). Now, here Silver nitrate reacts with Sodium hydroxide to form an insoluble hydroxide,
AgNO3 + NaOH à NaNO3 + AgOH (white precipitate)
Thus white precipitate formed is Silver Hydroxide (AgOH).
Solution 1: Sodium Hydroxide (NaOH)
Solution 2: Ammonium Hydroxide (NH4OH)
Solution 3: Copper (II) Chloride (CuCl2)
Solution 4: Potassium Chloride (KCl)
Solution 5: Silver Nitrate (AgNO3)
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