Question

Predict which solutions will have a higher electrical conductivity: 14.22 g of cobalt (II) nitrate in 57.8 mL of water or 9.528 g of copper (II) chloride in 32.9 mL of water.

Answer 1

molarity of cobalt(II) nitrate = [mass/ molarmass]/V(L)

= [14.22g/182.94g/mol)/0.0578L

=1.345 mol/L

Co(NO3)2 (aq) ----------> Co+2 + 2NO3-

1.345 2x1.345

Total ions = 1.345 + 2.690 = 4.035moles of ions

molarity of copper (II) chloride = [ 9.528g/134.45g/mol] /0.0329L

=2.153 mol/L

As the molarity of CuCl2 > Co(NO3)2 , both give te same number of ions, CoCl2 has higher electrical conductivity than cobalt nitrate.