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The reaction between 1-chloro-1-phenylethane and hydroxide ions to produce 1-phenylethanol is: C₆H₅CHClCH₃ + OH⁻ → C₆H₅CH(OH)CH₃ + Cl⁻ The rate of this reaction can be studied by measuring the amount of hydroxide ions that remain in solution at a given time - CIE - A-Level Chemistry - Question 6 - 2017 - Paper 1
Question 6
The reaction between 1-chloro-1-phenylethane and hydroxide ions to produce 1-phenylethanol is: C₆H₅CHClCH₃ + OH⁻ → C₆H₅CH(OH)CH₃ + Cl⁻ The rate of this reaction ca... show full transcript
Worked Solution & Example Answer:The reaction between 1-chloro-1-phenylethane and hydroxide ions to produce 1-phenylethanol is: C₆H₅CHClCH₃ + OH⁻ → C₆H₅CH(OH)CH₃ + Cl⁻ The rate of this reaction can be studied by measuring the amount of hydroxide ions that remain in solution at a given time - CIE - A-Level Chemistry - Question 6 - 2017 - Paper 1
Step 1
Describe a suitable method for studying the rate of this reaction at a temperature of 40°C.
Answer
To study the reaction rate:
- Prepare solutions A (0.10mol dm⁻³ 1-chloro-1-phenylethane) and B (0.10mol dm⁻³ sodium hydroxide) in separate volumetric flasks.
- Place both solutions in an ice-bath at 40°C to ensure they are at the required temperature before mixing.
- Measure equal volumes of solutions A and B and mix them together rapidly in a reaction vessel.
- Use a stopcock to draw a sample at known time intervals to monitor the concentration of hydroxide ions remaining.
- Dilute the reaction mixture with an ice-cold solvent to stop the reaction, ensuring accurate rate measurements can be made.
- Use back-titration with HCl to determine the amount of hydroxide ions remaining at each time interval.
Step 2
Deduce the order of reaction with respect to each [C₆H₅CHClCH₃] and [OH⁻].
Answer
To analyze the order of reaction:
- From experiments 1 to 2, when [C₆H₅CHClCH₃] is doubled, the relative rate doubles, indicating that the order with respect to [C₆H₅CHClCH₃] is 1.
- From experiments 2 and 3, when [OH⁻] is doubled and [C₆H₅CHClCH₃] remains constant, the relative rate does not double, suggesting that the order with respect to [OH⁻] is 0.
Step 3
Calculate the relative rate for experiment 4.
Answer
From the data provided:
- Using the relationship determined from previous experiments, we observe that if the concentrations in experiment 4 are used in conjunction with known relative rates from experiments 1 and 2, we can calculate the relative rate. If the stoichiometric relationships hold true, and considering the concentrations used, the estimated relative rate for experiment 4 is 2.0.