Question

Problem 15.61 Which of the following gives a buffer solution when equal volumes of the two solutions are mixed? Check all that apply. a) 0.20 M NH3 and 0.10 M HCl b) 0.20 M NH4Cl and 0.10 M NaOH c) 0.10 M NH3 and 0.10M HCl d) 0.10 M NH4Cl and 0.10M NH3

Answer 1

answers : except c , remaining all are buffers a, b ,d

explanation:

a) 0.20 M NH3 and 0.10 M HCl :

NH3 + HCl ----------------> NH4Cl

0.20      0.10                           0 --------------> initial

0.10         0.0                          0.10 --------------> after reaction

here base NH3 + salt NH4Cl remains so it is buffer

b) 0.20 M NH4Cl and 0.10 M NaOH

   NH4Cl + OH- --------------> NH4OH

    0.2            0.1                         0.0

0.1                0.0                        0.1

here also NH4Cl + NH4OH remains . so it is also buffer

c) 0.10 M NH3 and 0.10M HCl

total NH3 and HCl are consumed . only NH4Cl salt is remains . so it is not buffer

d) 0.10 M NH4Cl and 0.10M NH3

NH4Cl and NH3 are present . so it is also buffer