Study

Chemistry 1. Explain why 0-nitrophenol has a lower boiling point than p-nitrophenol? 2. Why alkali metals used in photoelectric cells? 3. Due to which compound, ozone depletion is caused in Antarctica? 4. Which of the element among B, Al, C and Si :- a. Has the highest first ionization enthalpy? b. Has the most negative electron gain enthalpy? 5. c. Write the atomic number of the element present in the third period and seventeenth group of the periodic table. d. Out of the elements Cr (Z-24), Mg (Z=12), and Fe (Z=26), identify the element with five electrons in 3d sub shell. 6. Critical temperature of ammonia and carbon dioxide are 405.5 K and 304.10 K respectively. Which these gases will liquefy first when you start cooling from 500K to their critical temperature 7. An element ‘A’ belongs to group 2 of the periodic table. It shows anomalous behavior from the rest of the elements of its group. It shows a diagonal relationship with another element ‘B’. Chlorides of both ‘A’ and ‘B’ have bridged structure in vapour phase. Identify A and B and draw the structures of their respective chlorides. 8. Calculate the mass percent of different elements in sodium sulphate (Na2SO4). 9. Why does the rain water normally have a pH of about 5.6? When does it become acid rain? 10. The threshold frequency for the ejection of electron from a metal is 5 X 1014 s-1. Will the photon of radiation having energy 3.0 X 10-19 J give photo electric effect or not? 11. A metal ‘X’ is present in chlorophyll. Identify the metal ‘X’. write the reaction of this metal with N2. 12. An orbital has n=3. What are the possible values of l and m l ? 13. Explain the hybridization of PCl5 molecule. Why PCl5 on decomposition gives PCl3 and Cl2 ? 14. Consider the chemical reaction:
2SO2 (g) + O2 (g) 2SO3 (g) +189.4 KJ. Indicate the direction in which the equilibrium will shift when:- e. Temperature is increased.