JEE Main 2016 · Chemistry · Biomolecules and Polymers · easy

Nylon-6,6 is made from hexamethylenediamine (M=116) and adipic acid (M=146) with loss of water. To prepare 4.52 g of nylon-6,6 (repeat unit…

Single correct option

Nylon-6,6 is made from hexamethylenediamine (

M=116

) and adipic acid (

M=146

) with loss of water. To prepare

4.52\ \mathrm{g}

of nylon-6,6 (repeat unit

\mathrm{C_{12}H_{22}N_2O_2}

M=226

) in

90\%

yield, the mass of adipic acid required is nearly

Show answer and solution

Answer: (C) $3.24\ \mathrm{g}$

Each repeat unit is formed from one diamine and one diacid minus

2\mathrm{H_2O}

116+146-36=226

4.52\ \mathrm{g}

polymer is

0.020

mol of repeat units, requiring

0.020

mol of adipic acid at

100\%

yield:

0.020\times146=2.92

g. At

90\%

yield the amount of reactant must be larger:

2.92/0.90=3.24

g. The

2.92

g option ignores the yield,

3.60

g divides by

0.81

(applies the yield twice), and

2.58

g is the diamine requirement adjusted for yield.

Original question written in the JEE Main 2016 pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake