Kinetics II
1. This question has 2 part(s).
1.1. Gentian violet is a purple crystalline solid used as an antifungal treatment.
It can be synthesised from dimethylphenylamine, C6H5N(CH3)2.
The dimethylphenylamine used in the synthesis can be made by the stepwise reaction of phenylamine with chloromethane.
Step 1
Step 2
The reaction mechanism for Step 1 between phenylamine and chloromethane is the same as that in the reaction between ammonia and chloromethane.
i) What is the reaction type and mechanism in Step 1?
(1)
☐ | A | electrophilic addition |
☐ | B | electrophilic substitution |
☐ | C | nucleophilic addition |
☐ | D | nucleophilic substitution |
ii) Draw the mechanism for the reaction in Step 1. Include curly arrows, and relevant lone pairs and dipoles.
(4)
iii) Describe, in outline, how a sample of a solid, such as gentian violet, is purified by recrystallisation. Specific details of the solvent used are not required.
(4)
1.2. The rate constant for the reaction between a solution of gentian violet and aqueous sodium hydroxide was determined at different temperatures.
Temperature (T) | 1/ Temparature (1/T) /K-1 | Rate constant, k | In k |
283.5 | 3.53 x 10-3 | 2.71 x 10-3 | —5.91 |
287.5 | 3.48 x 10-3 | 3.55 x 10-3 | |
291.5 | 4.75 x 10-3 | —5.35 | |
295.0 | 3.39 x 10-3 | 6.10 x 10-3 | —5.10 |
298.5 | 3.35 x 10-3 | 7.60 x 10-3 | —4.88 |
i) Complete the data in the table.
(1)
ii) Plot a graph and use it to determine the activation energy for the reaction in kJ mol-1.
You should include the value and units of the gradient of the line.
The Arrhenius equation can be shown as
(6)
Gradient
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Activation energy
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Ai এর মাধ্যমে
১০ লক্ষ+ প্রশ্ন ডাটাবেজ
প্র্যাকটিস এর মাধ্যমে নিজেকে তৈরি করে ফেলো
উত্তর দিবে তোমার বই থেকে ও তোমার মত করে।
সারা দেশের শিক্ষার্থীদের মধ্যে নিজের অবস্থান যাচাই
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