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.
Potential environmental impacts and obstacles of solar energy. Solar energy is considered a sustainable energy supply technology however, the production technology for solar modules (which are used to convert energy into power) requires relatively high energy outputs. The predominant negative environmental impacts of solar energy come from producing the solar panels. Production of these panels consumes substantial amounts of energy and produces waste water and hazardous by-products which are released to the air during the manufacturing process.