XII Standard - 12th - Chemistry - First Midterm Test Question Paper - Samacheer Kalvi

 

First Mid Term Test

Class: XII                                                                                                    Marks: 70

Sub: CHEMISTRY                                                                                   Duration:3:00 Hrs.

Part - A

I. Choose the correct answer from the given options below:                    15x1=15

1. Bauxite has the composition

   a)        b)  n.O         c)  .2O         d) None of these

2. The incorrect statement among the following is ----------

   a) Nickel is refined by Mond’s process

   b) Titanium is refined by Van Arkel’s process

   c) Zinc blende is concentrated by froth floatation

   d) In the metallurgy of gold, the metal is leached with dilute sodium chloride     solution

3. Which one of the following ores is best concentrated by froth – floatation   method?

    a) Magnetite   b) Haematite              c) Galena                    d) Cassiterite

4. The element that does not show catenation among the following p-block element is---------

   a) Carbon        b) silicon                    c) Lead                        d) germanium

5. Which of the following is not  hybridised?

    a) Graphite    b) grapheme                c) Fullerene                 d) dry ice

6. An aqueous solution of borax is----------

    a) neutral       b) acidic                      c) basic                        d) amphoteric

7. Graphite and diamond are---------

    a) Covalent and molecular crystals        b) ionic and covalent crystals

    c) both covalent crystals                         d) both molecular crystals

8. The vacant space in bcc lattice unit cell is----------

    a) 48%           b) 23%                        c) 32%                          d) 26%

9. Solid  is an example of---------

    a) Covalent solid     b) metallic solid   c) molecular solid     d) ionic solid

10. The addition of a catalyst during a chemical reaction alters which of the    following quantities?

   a) Enthalpy           b)Activation energy     c) Entropy            d) Internal energy

11. The rate constant of a reaction is  5.8 x   . The order of the reaction is

   a) First order        b) zero order          c) Second order           d) Third order

12. If the initial concentration of the reactant is doubled, the time for half  reaction is also   

      doubled. Then the order of the reaction is----------

   a) Zero                  b) one                    c) Fraction                   d) none

13. Which of the following compound can be used as artifreeze in automobile radiators?

   a) methanol           b) ethanol              c) Neopentyl alcohol   d) ethan -1, 2-diol

14. On reacting with neutral ferric chloride, phenol gives--------------

   a) red colour         b) violet colour      c) dark green colour     d) no colouration.

15. Which one of the following will react with phenol to give salicyladehyde after hydrolysis?

    a) Dichloro methane b) trichloroethane c) trichloro methane d)

 

PART-B

II. Answer any 6 of the following questions: Q.NO 24 is Compulsory.    6x2=12

16. Draw the major product formed when 1-ethoxyprop-1-ene is heated with one equivalent of

      HI.

17. What happens when 1-phenyl ethanol is treated with acidified KMn?

18. Which type of ores can be concentrated by froth floatation method? Give two examples for  such ores.

19. Give the two uses of zinc.

20. Write a note on Fisher tropsch synthesis.

21. How will you convert boric acid to boron nitride?

22. Define average rate and instantaneous rate.

23. Explain the following terms with suitable examples.

     (i) Gangue (ii) slag

24. Sodium metal crystallizes in bcc structure with the edge length of the unit cell 4.3 x   cm.

      calculate the radius of sodium atom.

 

PART-C

III. Answer any 6 of the following questions: Q. No 33 is compulsory.   6x3=18

25. How will you identify borate radical?

26. A hydride of 2nd period alkali metal (A) on reaction with compound of Boron (B) to give a

      reducing agent (C). identify A, B and C.

27. Distinguish tetrahedral and octahedral voids.

28. Explain the rate determining step with an example.

29. Define rate law and rate constant.

30.What is the two dimensional coordination number of a molecule in square close packed layer?

31. Explain Kolbe’s reaction.

32. What is the major product obtained when two moles of ethyl magnesium bromide is treated

      with methyl benzoate followed by acid hydrolysis

 

PART-D

IV. Answer all the questions:                                                                                   5x5=25

34. a)   (i)  Explain the electrometallurgy of aluminium.

            (ii) Give the limitations of Ellingham diagram.         

(OR)

      b)    Describe the role of the following in the process mentioned.

            (i) Silica in the extraction of copper.

            (ii) Cryolite in the extraction of aluminium.

            (iii) Iodine in the refining of Zirconium.

            (iv) Sodium cyanide in froth floatation.

35.   a) (i)  Describe the structure of diborane.

            (ii) What is an elementary reaction? Give the differences between order and

                    molecularity of a reaction.

(OR)

        b) (i)  Write a note on zeolites.

            (ii) What is catenation ? Describe briefly the catenation property of carbon.

36.a) (i) Differentiate crystalline solids and amorphous solids.

           (ii) Classify the following solids

            a.       b. Brass       c. diamond      d. NaCl      e. Iodine                                                     

(OR)

      b) Calculate the percentage efficiency of packing in case of body centered cubic crystal.

37. a) Derive integrated rate law for a zero order reaction. A → Product   

(OR)

      b) (i) Explain the effect of catalyst on reaction rate with an example.

          (ii) Explain Schottky defect.

38. a)  Predict the major product, when 2-methyl but -2-ene is converted into an alcohol in each

      of the following methods.

     (i.) Acid catalysed hydration

     (ii.) Hydroboration

     (iii.) Hydroxylation using Baeyer's reagent        (OR)

b)  (i) How is phenol prepared from i) chloro benzene ii) isopropyl benzene

     (ii)What is metamerism? Give the structure and IUPAC name of metamers of 2-methoxy    

      propane