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Figure 1 shows some compounds made from a halogenoalkane - AQA - A-Level Chemistry - Question 1 - 2017 - Paper 2
Question 1
Figure 1 shows some compounds made from a halogenoalkane. Figure 1 Compound J Reaction 1 NaOH(aq) CH3CH2CH2Br Reaction 2 NH2 CH3CH2CH2NH2 Reaction 3 ... show full transcript
Worked Solution & Example Answer:Figure 1 shows some compounds made from a halogenoalkane - AQA - A-Level Chemistry - Question 1 - 2017 - Paper 2
Step 1
Step 2
Name the mechanism for Reaction 2 and give an essential condition used to ensure that CH3CH2CH2NH2 is the major product.
Answer
The mechanism for Reaction 2 is Nucleophilic substitution. An essential condition to ensure that CH3CH2CH2NH2 is the major product is to use excess ammonia (NH2).
Step 3
Calculate the mass, in grams, of CH3CH2CH2NH2 produced from 25.2 g of CH3CH2CH2Br in Reaction 2 assuming a 75.0% yield.
Answer
To calculate the mass of CH3CH2CH2NH2 produced:
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Calculate the moles of CH3CH2CH2Br:
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The reaction gives 1:1 molar ratio, so moles of CH3CH2CH2NH2 produced is also 0.204 mol.
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Calculate the mass of CH3CH2CH2NH2:
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Considering the yield:
Hence, the final answer is 11.2 g (to 3 significant figures).
Step 4
When Reaction 2 is carried out under different conditions, a compound with molecular formula C4H13N is produced. Draw the skeletal formula of the compound. Identify the functional group in the compound including its classification.
Answer
The skeletal formula of the compound C4H13N is:
H H
| |
H - C - C - C
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H N - H
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H
The functional group in the compound is an amine, which is classified as a tertiary amine.
Step 5
Step 6
Name and outline a mechanism for Reaction 3.
Answer
The mechanism for Reaction 3 is Base Elimination. The steps are:
- The lone pair on the hydroxide ion acts as a nucleophile and attacks the beta-hydrogen, forming a double bond.
- This results in the elimination of a halide ion, producing an alkene.