Calculate the electronegativity of Chlorine from bond energy of Cl – F bond (61 kcal mol−1) F−F (38 kcal mol−1) and Cl−Cl bond (58 kcal mol−1) and electronegativity of fluorine 4.0 eV
CHAPTER - 1 THE SOLID STATE
Q. In India, we have shortage of electricity. Electricity is being produced by hydel power, nuclear power, thermal power, gas power, etc. Which source like wind energy, tidal energy, solar energy is being used to some extent to generate power. Solar energy can be converted into electricity by special type of substances called photovoltaic material. Use of CFC' and LED" lamps can also save lot of electricity.
1. Name one photovoltaic material.
2. Why is solar power generation better than conventional way of generating power? Give one reason.
3. Why is solar power not very popular in India?
4. What are the value associated with above passage?
Calculate the electronegativity of Chlorine from bond energy of Cl – F bond (61 kcal mol−1) F−F (38 kcal mol−1) and Cl−Cl bond (58 kcal mol−1) and electronegativity of fluorine 4.0 eV
Q.15. Biochemical Oxygen Demand (BOO) value can be a measure of water pollution caused by the organic matter. Which of the following statements is correct ?
1. Clean water has BOD value higher than 10 ppm.
2. Aerobic bacteria decrease the BOD value.
3. Polluted water has BOD value higher than 10 ppm.
4. Anaerobic bacteria increase the BOD value.
Q. Viscosity of a liquid arises due to strong intermolecular forces existing between the molecules. Stronger the intermolecular forces, greater is the viscosity. Name the intermolecular forces existing in the following liquids and arrange them in the increasing order of their viscosities. Also give, reason for the
assigned order.
water, hexane and glycerine.
Name the intermolecular forces existing in the following liquids and arrange them in the increasing order of their viscosities. Also give reason for the assigned order.
Q.59. What diseases are caused by streptococcus infections? Name the chemical in the drugs to cure such infections.