Chemistry Class - XII 1996 (CBSE)
You are on Set no 1 Qno. 1 to 20

Time allowed : 3 hours
Maximum Marks : 70
General Instructions :

(i) All questions are compulsory.
(ii) Marks for each question are indicated against it.
(iii) Question number 1 to 10 are very short-answer questions each of 1 mark. Answer them in about one sentence each.
(iv) Question number 11 to 26 are short-answer questions of 2 marks. Answer them in not more than 30 words each.
(v) Question number 27 to 32 are short-answer questions of 3 marks. Answer them in not more than 40 words each.
(vi) Question number 33 to 34 are long-answer questions of 5 marks each. Answer them in not more than 70 words each.
(vii) Use Log Tables, if necessary.
(viii) Please write down the serial number of the question before attempting it.

Q1) Write the state of hybridisation of Boran in BCI₃.  (Marks 1)

Q2) What are the coordination number of each of the ions present in the cubic close packed structure of CaF₂ at ordinary temperature and pressure?  (Marks 1)

Q3) The rate constant of a reaction is 2 x 10^-2 L mol^-1 s^-1. What is the order of the reaction? (Marks1) 

Q4) Give the IUPAC name of the following compound:  (Marks 1)

				O
CH3		CH		C		CH		OCH2CH3
		CH3				CH3

Q5) Which alkali metal carbonate decomposes on heating to liberate CO₂?  (Marks 1)

Q6) Name the first element of the 3-d transition metal series.  (Marks 1)

Q7) Give the IUPAC name of the linkage isomer of [ (NH₃)₃ Pt-NO₂ ] Cl.  (Marks 1)

Q8) Fill in the blanks:
Alpha rays are fast moving ... nuclei.   (Marks 1)

Q9) Fill in the blanks:
The scattering of light by colloidal dispersion is called ...   (Marks 1)

Q10) If a fragment of one strand of DNA has the base sequence TACGGACAT, what is the base sequence of the complementary strand?   (Marks 1)

Q11) A solid AB has the NaCl structure. If a radius of the cation A⁺ is 120 pm, calculate the maximum possible value of the radius of the anion B^-.  (Marks 2)

Q12) The enthalpy change for the reaction
                   Ag₂O(s) 2Ag(s) + ½ O₂(g)
is 30.54 kJ mol^-1 and S = 0.06 kJ K¹ mol^-1 (at 1 atm). Calculate the temperature at which G is equal to zero. Also predict the direction of the reaction at a temperature below this calculated temperature.   (Marks 2)

Q13 What is standard hydrogen electrode? Give the reaction that occurs at this electrode when it acts as positive electrode in an electrode in an electrochemical cell.  (Marks 2)

Q14 Calculate the E.M.F. of the following cell at 298 K : (Marks 2)
                   Mg | Mg²⁺ (0.1 M) || Ag⁺ (0.1M) | Ag
Given:
    E°_Mg²⁺ _{/ Mg} = -2.37 V, E°_Ag+/Ag = 0.8 V,
    R=8.31 JK^-1 mol^-1, F= 96500 C mol^-1 

Q15 With the help of chemical reaction show how you convert 2-propanol to 1-bromopropane in two steps?  (Marks 2)

Q16) Give a chemical test to distinguish between ethanol and propanol. Write the balance chemical equation.  (Marks 2)

Q17) Predict the product of the following reaction and balance the equation:  (Marks 2)
                               heat
(a) C₆H₅OCH₃ + HBr
                       (cont.)        
                  
                  NaOH(dil.)
(b) CH₃CHO          
                 as catalyst

Q18) What is Sandmeryer's reaction? Illustrate with a suitable example.   (Marks 2)

Q19) What are interstitial compounds? Explain them with reference to transition metals and mention their two important properties.   (Marks 2)

Q20) Using valence bond approach, predict the shape and the magnetism (i.e. paramagnetic or dia-magnetic) of [Co(CO)₄]^-. (Atomic number of Co=27).   (Marks 2)