KENDRIYA VIDYALAYA ORDNANCE FACTORY DUMDUM
SUMMER VACATION HOLIDAY HOMEWORK
SUBJECT: CHEMISTRY CLASS-XII-A
SUBJECT TEACHER: Mr. PARTHA DATTA(PGT CHEM)
CHAPTER 1: THE SOLID STATE.
QUESTIONS: 1 MARK QUESTIONS
1. Name a liquefied metal which expands on solidification.
2. How many number of molecules per unit cell which crystallizes in the form of end face centred (monoclinic) lattice with a molecule at each lattice.
3. What is the coordination number of carbon, in diamond?.
4. Name the solid which has weakest intermolecular force?
5. Arrange the following types of interactions in correct order of their increasing strength : Covalent, hydrogen bonding, Vander Waals, dipole dipoleinteraction
6. Give reason for the appearance of color in alkali metal halides.
7. Which type of defect occur in AgBr ?
2 MARKS QUESTIONS:
8. Define the term ‘amorphous’.Givetwo examples of amorphous solids.
9. What makes a glass different from a solid such as quartz ? Under what condition quartz couldbe convertedinto glass ?
10. How can you determine the atomic mass of an unknown metal if you know its density and the dimension of its unit cell?
11.If the radius of octahedral voids is ‘r’ and radius of atoms in close packing is R, derive relation between r and R.
12. What is semiconductor? Describe the two main types of semiconductor and contrast their conduction mechanism?
13. How many unit cells are present in a cube shaped ideal crystal of NaCl of mass 1 gm ?
14. In the mineral spinal; having the formula MgAl2O4 . The oxide ions are arranged in CCP, Mg2+ ions occupy the tetrahedral voids. While Al3+ ions occupied the octahedral voids.What percentage of tetrahedral voids is occupied by Mg2+ions ?
15. Givereasons: (a) Window glass of old building look milky. b) Window glass of old building is thick at bottom. (c) CaCl2 will introduce Schottky defect if added to AgCl crystal.
16. Analysis shows that nickel oxide has the formula NiO0.98O1.00. What fractions of nickel exist as Ni2+ and Ni3+ ions?
17. What type of defect can arise when a solid isheated? Which physical property is affected by this and in what way?
18. What happens when a Ferromagnetic or Ferrimagnetic solid is heated?
19. How n-type and p -type semi conductors are obtained?
CHAPTER 2: SOLUTIONS
1. Define the term solution. How many types of solutions are formed? Write briefly about each type with an example.
2. Define the terms: i)Mole fraction ii)Molarity iii)Molality iv)Mass percentage
3. Concentrated nitric acid used in laboratory work is 68% nitric acid by mass in aqueous solutions. What should be the molarity of such a sample of the acid if the density of the solution is 1.504g/ml?
4. State Henry’s law and mention some important applications?
5. The vapour pressure of water is 12.3kPa at 300K.calculate vapour pressure of 1 molal solution of a non-volatile solute in it.
6. A sample of drinking water was found to be severely contaminated with chloroform (CHCl3) supposed to be a carcinogen. The level of contamination was 15 ppm(by mass):
7. Express this in percentage by mass.
8. Determine the molality of chloroform in the water sample.
9. The vapour pressure of deliquescent substance is less or more than that of water vapours in air ?
10. If a is the degree of dissociation of Na2SO4 then write the Vant Hoff factor used for calculating the molecular mass.
11. If 6.023 × 1020 molecules of urea are present in 100 ml of its soln. then what is the conc. of urea soln. ?
12. 0.004 M soln of Na2SO4 is isotonic with 0.01 M soln of glucose at the temp. What is the apparent degree of dissociation of Na2SO4 ?
13. What happen when mango is placed in dilute aqueous soln of HCl ?.
14. Out of (a) 200 ml of 2 M NaClSoln and (b) 200 ml of 1 M glucose Soln. which one has higher osmotic pressure ?
15. Out of (a) 0.01 M KNO3 (b) 0.01 M Na2SO4 which aqueous soln. will exhibit high B. P?
16. Out of (a) 1 M CaCl2 (b) 1 M AlCl3 which aqueous soln. will show max. vapour pressure at 300 K ? If we assume 100% dissociation, i for CaCl2 = 3 and AlCl3 = 4 and relative lowering of V. P. is directly proportional to i.
17. Out of (a) HNO3 + H2O and (b) C6H6 + C6H5CH3 which will form max. Boiling azeotrope ?
18. Why water cannot be separated completely from ethyl alcohol by fractional distillation?
19. Why a person suffering from high blood pressure is advised to take minimum quantity of common salt?
WISH YOU HAPPY& PROSPERROUS SUMMER VACATION.
THANK YOU.
THE END.