250+ TOP MCQs on Synthetic Organic Chemical – Styrene and Answers

Chemical Technology Multiple Choice Questions on “Synthetic Organic Chemical – Styrene”.

1. Which process is used for the manufacture of styrene?
a) Dehydrogenation of ethyl benzene
b) Hydrogenation of acetophenone
c) Hydrogenation of toluene
d) Benzene sulphurated process

Answer: a
Clarification: Styrene is manufactured first by alkylation of benzene followed by dehydrogenation of ethyl benzene. Hydrogenation of toluene is used for the manufacture of benzene.

2. Benzene is alkylated with ethylene for the manufacture of styrene.
a) True
b) False

Answer: a
Clarification: Benzene is alkylated with ethylene by Friedel craft method using aluminum chloride or any other acid type catalyst.

3. Alkylation in manufacture of styrene must be done under wet condition.
a) True
b) False

Answer: b
Clarification: Alkylation operation must be done under very dry conditions with high purity feed stock to avoid activity loss of the catalyst. All benzene feed must be dry by azeotropic distillation.

4. How is crude acidic ethyl benzene is neutralized in the manufacture of styrene?
a) Adding HCl
b) Adding H2SO4
c) Adding NaOH
d) Adding NaCl

Answer: c
Clarification: Crude acidic ethyl benzene from the coolers is neutralized with 50% NaOH solution stripped to remove polyethyl benzene and the overhead is sent to the benzene column which separates wet benzene from ethyl benzene.

5. How is traces of tar and Sulphur removed from styrene?
a) O-tertiary catechol
b) P-tertiary catechol
c) NaOH
d) KOH

Answer: b
Clarification: The styrene which was stabilized with p-tertiary catechol is vacuumed distilled to remove traces of tar and Sulphur. The final overhead is refrigerated at 10 degree Celsius.

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