Question

Considering 0.10 m solutions of each substance, which contains the smallest concentration of ions

Answer 1

Question options:

A) K2SO4

B) FeCl₃

C) NaOH

D) NH₃

E) KCl

Answer:

D. NH₃

Explanation:

K2SO4 = 2 K+ + SO42-

[K+]= 2 x 1.0 = 2.0 M ; [SO42-] = 1.0 M

total concentrations of ions = 2.0 + 1.0 = 3.0 M

FeCl3 = Fe3+ + 3Cl-

[Fe3+] = 1.0 M ; [Cl-] = 3 x 1.0 = 3.0

total concentration ions = 1.0 + 3.0 = 4.0 M

NaOH = Na+ + OH-

[Na+] = [OH-] = 1.0 M

total concentration ions = 1.0 + 1.0 = 2.0 M

NH3 is a weak acid so the concentration of NH4+ and OH- < 2.0

KCl = K+ + Cl-

[K+] = [Cl-] = 1.0 M

total concentration ions = 1.0 + 1.0 = 2.0 M