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.
1. Solar energy is free although there is a cost in the building of collectors and other equipment required to convert solar energy into electricity or hot water. 2. Solar energy does not cause pollution. However, solar collectors and other associated equipment / machines are manufactured in factories that in turn cause some pollution. 3. Solar energy can be used in remote areas where it is too expensive to extend the electricity power grid.