Question

Question Completion Status QUESTION 15 10 points are A Aaygroupe de recting ACOCH) and even ee n anderen C. A rendre l e groupe de practing D. Crew metho d s to decide directing QUESTION 16 1. She nese obtained an 80 yield of 4-bromoacetanilide in her bromination of acetanilide reaction. She started with 10 grams of acetanilide molar mas What mass of 4-bromoacetandide molar mass - 214.06/mol) did she obtain? u mo

Answer 1

15)

Option "D" is incorrect.

Both chlorine (halogens) and methoxy (alcoxy) groups are ortho-para directing, but chlorine is a deactivating group and methoxy groups are strong activating.

Halogens are deactivating groups but they are ortho-para directing, not meta because of two reasons

• High electronegativity of halogens causes inductive withdrawal (withdrawal of electrones from aromatic ring)
• Non-bonding electrons in halogens are donated by resonance donation

All other options are correct due to

A) Alkyl groups are weaky activating (+M effect) and ortho-para directing

B) Acetyl and Cyano groups are deactivating due to -I and -M effect. Both are meta directing

C) Ammonium groups are deactivating due to -I effect and meta directing where amino groups are activating due to +M effect and ortho-para directing

16)

104 Н acetanilide 4-Bromoacetanilide

One mol of acetanilide gives one mol of 4-Bromoacetanilide. Since 3g of acetanilide were taken,
Number of moles of acetanilide taken = weight taken/molecular weight
= 3/135.17
= 0.0222 mol
Since One mol of acetanilide gives one mol of 4-Bromoacetanilide, 0.0222mols of acetanilide should give 0.0222 mols of 4-Bromoactanilide (100% yield).
ie, weight of 4-Bromoacetanilide obtained to get 100% yield = no: of mols x molecular weight
= 0.222 x 214.06
= 4.752 grams
Since she got only 80% yield the weight of 4-Bromoacetanilide obtained = (4.752 x 80) / 100
= 3.80 grams

The answer is option "B"

17)

In the workup for reaction mixture obtained from the synthesis of 4-Bromoacetanilide from acetanilide, addition of sodium bisulphite is to quench the excess unreacted bromine in the reaction   mixture. Since sodium sulphite is reducing agent it will convert bromine into bromide and this bromide ions can be easily removed from aqueous layer.

This is the reason and i cannot choose options because options are not clear

I am sorry that I couldn't read question number 18 since the uploaded picture is not clear. Due to that I am not able to answer that question. It would be very helpful if clear pictures are used as questions.