Polarity and Boiling Point: The polarity of the molecules determines the forces of attraction between the molecules in the liquid state. Polar molecules are attracted by the opposite charge effect (the positive end of one molecule is attracted to the negative end of another molecule.
The five disadvantages of solar power. It's intermittent. Solar energy is only available when the sun is shining. It's low efficiency. It requires large areas of land. It's not completely free of environmental impact. Ultrapure polysilicon is now scarce. It's high cost.
However, problems with solar energy, namely the expensive cost and inconsistent availability, have prevented it from becoming a more utilized energy source. Solar power makes up less than 0.5% of all power produced in North America even though there are vast regions of the continent where the sun continuously shines.