What are the total concentrations of ions in the following solutions?

0.1 mol/L propanol
0.1 mol/L sucrose
0.1 mol/L HClO;Ka=2.9×10-8
0.10 mol/L HClO3
0.10 mol/L LiClO4
0.10 mol/L CuSO4

1 Answer
Oct 16, 2016

Warning! Long answer! These are the concentrations of ions in 0.1 mol/L aqueous solutions.

Explanation:

The calculations start from the premise that water contains 1.0×10-7lmol/L H3O+ and 1.0×10-7lmol/L HO-, for a total ion concentration of 2.0×10-7lmol/L.

0.1 mol/L Propanol and 0.10 mol/L Sucrose

Propanol and sucrose are nonelectrolytes.

They do not generate ions, so the total ion concentration is the same as in pure water: 2.0×10-7lmol/L.

0.10 mol/L HClO

HClO is a weak acid with Ka=2.9×10-8

mmmmmmmHClO+H2OH3O++ClO-
I/mol⋅L-1:mm0.10mmmmmmm0mmmm0
C/mol⋅L-1:mm-xmmmmmmm+xmmm+x
E/mol⋅L-1:l0.10xmmmmmmlxmmmllx

Ka=[H3O+][ClO-][HClO]=x×x0.10x=2.9×10-8

0.102.9×10-8=3.4×106, so x0.10

x20.10=2.9×10-8

x2=0.10×2.9×10-8=2.9×10-9

x=5.4×10-5

[H3O+]=[ClO-]=5.4×10-5lmol/L

Total ion concentration=2×5.4×10-5lmol/L=1.1×10-4lmol/L

0.10 mol/L HClO3

HClO3 is a strong acid.

mmmmmmllHClO3+H2OH3O++ClO-3
I/mol⋅L-1:mm0.10mmmmmmml0mmmm0
C/mol⋅L-1:ml-0.10mmmmmm+0.10mll+0.10
E/mol⋅L-1:mml0mmmmmmmll0.10mmll0.10

[H3O+]=[ClO-3]=0.10 mol/L

Total ion concentration=2 × 0.10 mol/L=0.20 mol/L

0.10 mol/L LiClO4 and 0.10 mol/L CuSO4

LiClO4 and CuSO4 are strong electrolytes.

Here is the calculation for LiClO4.

mmmmmmmLiClO4Li++ClO-4
I/mol⋅L-1:mm0.10mmmll0mmml0
C/mol⋅L-1:ml-0.10mml+0.10m+0.10
E/mol⋅L-1:mml0mmmm0.10mm0.10

[Li+]=[ClO-4]=0.10 mol/L

Total ion concentration=2 × 0.10 mol/L=0.20 mol/L