What is the principle of LIKE DISSOLVES LIKE ,EXPLANATION needed,and also limitations?

1 Answer
Jun 15, 2018

Polar solvents dissolve polar solutes....of course there is a catch...


Polar solvents TEND to dissolve polar solutes....and non-polar solvents TEND to dissolve non-polar solutes...but this is a VERY general rule of thumb. And here when we say #"polar"# we mean #"charge-separated"#.

Water is an exceptionally polar solvent, and is capable of solvating MANY ionic species, and many species that are capable of hydrogen-bonding, for instance the SHORTER alcohols. Methanol, and ethanol in particular are infinitely miscible with water.

On the other hand, non-polar solvents such as hexanes, are capable of (sometimes) dissolving non-polar solutes. Hexanes is miscible with ethanol (because of the two-carbon chain), but IMMISCIBLE with methanol (a ONE carbon chain). And there are also polar solvents such as diethyl ether, and methylene chloride, that while incapable of dissolving ionic solutes, are nevertheless GOOD solvents for many organic solutes.

So how do you know which solute is soluble in which solvent? How else by experiment? And polar or not, MOST solutes HAVE SOME solubility in water, one of the most powerful solvents known.

Confused yet?