Laboratory Practical 1 EXPERIMENTAL PROCEDURE Ersparation: Clean and dry four 40
ID: 713843 • Letter: L
Question
Laboratory Practical 1 EXPERIMENTAL PROCEDURE Ersparation: Clean and dry four 400 mL. beakers and one 600-1000 mL beaker. Label each of the four 400 mL beakers as Solution A, Solution B, Solution C, and Solution D. Prepare a stock solution of bleach in a 125 or 250 mL Erlenmeyer flask by diluting 15 mL of chlorine bleach with 45 mL of distilled water. Label this as Stock Solution of Bleach. Prepare solutions A-D as follows: SolutionA: Dissolve 0.60 g of potassium iodide in 100 mL of 1 M aqueous acetic acid, then add Solution B: Add 5 mL of the stock solution of bleach to 95 mL of distilled water Solution C Dissolve 2.50 g of magnesium sulfate heptahydrate in 100 mL of water Solution D Measure 100 mL of a 1.0 M solution of aqueous ammonia (ammonium h Presentation . Pour Solution A into Solution B. Which reaction is taking place? What type of reaction is it? 2.5 mL ofa 1% starch solution. 0.75 g of ascorbic acid in the solution. Pleie ansuer me Write a complete and balanced reaction equation as wetf as the net ionic reaction equation that describes this reaction. What is responsible for the color change? following page. Reductien Consider items I and 2 on the oxidation 2. Pour Solution C into Solution D. What reaction is taking place? What type of reaction is it? Write a complete and balanced reaction equation as well as the net ionic reaction equation that describes this reaction. What is responsible for the color change? Consider items 3 and 4 on the following page. 3. Now pour the two reaction mixtures simaltaneously into the larger 600- 1000 mL beaker. What What type of reaction is i? Write a complete and balanced reaction are the products from the previous two reactions that are responsible for the reaction that takes equation as well as the net ionic reaction equation that describes this reaction. Identify the spectator ions. What is responsible for the color change? Consider Items 2, 3, and item 5 on the following page. water (prodvit) ac (Monesm i d (no move soiid precpitation dseppeor Essential Concepts Demonstrations 29 SFSU CHEM 2Explanation / Answer
1) when solution A is poured in solution B the following reaction occurs
It is a redox reaction
The ionic reaction is:
ClO + 2H+ + 2I I2 + Cl + H2O [Reduction of bleach, conversion of Cl+ to Cl-]
The colour change is due to adsorption of Iodine molecule by starch which forms a complex which is blue in colour
2) On mixing C and D there will be reaction between magnesium sulphate and ammonium hydroxide
MgSO4 + 2NH4OH --->Mg(OH)2 + (NH4)2SO4
This is neutralization reaction
There is formation of white ppt of magnesium hydroxide
3) ascorbic acid is a reductant so it will reduce the iodine molecule back to iodide ion
The reaction is redox reaction
The reactio will be
ascorbic acid + I2 --->2HI + dehydroascorbic acid.
net ionic equation will be
ascorbic acid + I2--->2I- + dehydroascorbic acid
The spectator ions are H+
The complex between starch and iodine molecule will break which fades the blue colour
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