First find the number of moles of aluminium sulfate using n=m/MM
n(Al2SO43)=34.2/342.15
n(Al2SO43)=0.1
Now find the ratio of the ions in the aluminium sulfate (which is 2Al^3+: 3(SO4)^2-) and multiply these ratios by the original number of moles of aluminium sulfate.
Therefore the number of...