posted by ~christina~ on .
statement from my text says:
"like disolves like", This rule is most commonly applied to polar and nonpolar compounds. According to this rule, a polar solvent will dissolve polar(or ionic) compounds and non polar solven will dissolve nonpolar compounds.
For this statement I wanted to know if they mean polar substances are ionic or they mean a polar solvent will dissolve both polar and ionic compounds
and another part says:
...it is helpful to separate the types of solutions we will be looking at into 2 categories: solutions in which both the solvent and the solute are covalent(molecular) and ionic solutions, in which the solute ionizes and dissociates.
For this part it refers to once again their bracketed content. Are all covalent solutions molecular? According to how I'm reading this correctly then that's what it says but what do they mean by "molecular" then?
Polar substances MAY be ionic but they may also be polar coavalent.
A strictly covalent molecular often is referred to as molecular. Benzene might be such a sompound. CCl4 could be classified as a molecular compound. A strictly ionic bond makes an ionic compound. Then we have all of the shades of grey between strictly ionic and strictly covalent and we call them polar covalent.
Hm..then why do they say polar or ionic? Are they being vague then in the description?
Thanks Dr.Bob =)
Ionic solvents will dissolve ionize ionic compounds (like and like). Covalent compounds will dissolve covalent compounds (like and like). In addition, polar compounds (and most polar solvents are polar covalent compounds), will dissolve other polar compounds and if the polar solvent is polar enough, it will dissolve VERY polar (ionic) compounds. H2O, for example, is a polar covalent molecule, but it has no trouble dissolving many (probably most) ionic compounds. (like and like again). When they say "polar or ionic" they are making the distinction that not all polar molecules must be ionic.
Thanks for clearing that up, Dr.Bob =D