H.S.C. Board Practice Question Paper Set C

H.S.C. Board Practice Question Paper Set C

Date:    Feb 2016                                                    Sub.: Chemistry (55)                                          Seat Number:

Time: 3Hr.                                                   (Physical and Inorganic Chemistry)                                          Marks: 70   

Section I

Q. 1. Select and write the most appropriate answer from the given alternatives for each sub question. [7]

(i) p-type semiconductor is formed when trace amount of impurity is added to silicon. The number of valence electrons in the impurity atom must be

(a) 3       (b) 5       (c) 1       (d) 2

(ii) Relative vapour pressure lowering depends only on

(a)  Mole fraction of solute (b)  Nature of solvent

(c)  Nature of solute             (d)  Nature of solute and solvent

(iii) In the reaction, H_2(g) + Cl_2(g)2HCl_(g)

ΔH =- 184 kJ, if 2 moles of H₂ react with 2 moles of Cl₂, then ΔU is equal to

(a)  -184kJ              (b)  -368kJ

(c)  zero                  (d)   +368kJ

(iv) The standard potential for the cell reaction

2Tl_(s) + Hg²⁺_(1M)→ 2Tl⁺ _(1M) + Hg_(l)where E° _Tl = -0.34V, E°_Hg = 0.86V is

(a) 0.52V          (b) -0.52V         (c) -1.2V       (d) +1.2V

(v) Molecularity of an elementary reaction

(a) may be zero                      (b) is always integral

(c) may be semi-integral      (d) may be integral, fractional or zero.

(vi) Zone refining is a method to obtain:

(a) Very high temperature              (b) Ultra pure Al

(c) Ultra pure Germanium              (d) Ultra pure oxides

(vii) Noble gas used in the miner's cap lamp is

(a) krypton              (b) argon            (c) helium           (d) radon

Q. 2. Answer any SIX of the following.                                                                                                                   [12]

(i) Explain AAAA type two dimensional close packing.

(ii) State and explain van't Hoff-Avogadro'slaw.

 (iii) State and explain Hess's law of constantheat summation. Give it application.

(iv) Write cell reactions in lead storage battery during discharge.

(v) What is the molecularity of the following reaction?

     (1) O_3(g)→O_2(g) + O_(g)

     (2) 2NO_2(g)→ 2NO_(g) + O_{2 (g)}

(vi) Mention names and formulae of two ores of aluminium.

(vii) Name and draw the structures of different oxyacids of phosphorus.

       (1) Hypophosphorous acid

        (2) Orthophosphorous acid.

(viii) What is the standard hydrogen electrode OR Primary reference electrode? Write the construction and working of it.

Q.3. Answer any THREE of the following.                                                                                                               [09]

(i) Calculate the mass in gm of an impurity molar mass 100 gm mol^-1 which would be required to raise the     

     boiling point of 50gm of chloroform by 0.30K.

(ii) Calculate ΔS_Total and hence show whether the following reaction is spontaneous at 25°C.

      HgS_(s) + O_2(g)Hg_(l) + SO_2(g)ΔH° = –238.6KJ ΔS° = +36.7 JK^–1.

(iii) Write the cell reaction and calculate the emf of the cell at 25°C. Cr_(s) |Cr³⁺_(0.0065M) || Co²⁺_(0.012M) |Co_(s)

         E°_Co = - 0.280 V, E°_Cr = -0.74 V. What is ∆G for the reaction? 

(iv) Explain contact process of the manufacture of sulphuric acid.

Q. 4. Answer the following any ONE of the following.[07]

(i) (a)Write the structures of oxyacids of sulphur

          (1) Pyrosulphuric acid

          (2) Pyrosulphurous acid.

     (b) Define and explain with suitable examples:

          (1) Flux  

          (2) Slag.

     (c) Consider the reaction 2A + B                  2C. Suppose that at a particular moment during the reaction,

         rate of disappearance of A is 0.076M/s,

          (1) What is the rate of formation of C?

          (2) What is the rate of consumption of B?

          (3) What is the rate of the reaction?

(ii) (a) Describe the construction and working of Hydrogen-oxygen fuel cell.

      (b) Explain with reason sign convention of ΔS in the following reactions

           (1) N_2(g) + 3H_2(g)2NH_3(g)

           (2) CO_2(g)CO_2(s)

           (3) Solid I₂ dissolved in water

      (c) State and explain van't Hoff-Boyle's law. 

Section: II

Q. 5. Select and write the most appropriate answer from the given alternatives for each sub question. [07]

(i) The properties of Zr and Hf are similar because

(a) both have same atomic radii                    (b) both belong to d-block

(c) both belong to same series                        (d) both have same number of electrons

(ii) Cis-platin compound is used in the treatment of:

(a) malaria                (b) cancer

(c) AIDS                     (d) yellow fever

(iii) Which one of the following alkane is NOT formed in Wurtz reaction?

a) Methane     b) ethane

c) propane       d) butane

(iv) Which of the following alcohols is prepared by acid catalysed hydration of alkenes?

(a) Butan - 1 - ol         (b) Propan - 1 - ol

(c) ethanol                   (d)methanol

(v) The smell of bitter almond is given by the compound.

(a) Benzoic acid          (b) Benzaldehyde                   

(c) vanillin                   (d) cinnamaldehyde

(vi) The amine which reacts with nitrous acid to give yellow oily compound is

(a) ethyl amine          (b) isopropyl amine

(c) secondary amine (d) dimethyl amine

(vii) Which of the following is a bactericidal antibiotic?

a) Erythromycin     b) Ofloxacin

c) Tetracycline        d) Chloromphenical

Q. 6. Answer any SIX of the following.                                                                                                                    [12]

(i) Calculate the magnetic moment of Fe²⁺_(aq) ion (Z=26).                                        

(ii) Explain the terms  Inner sphere.

(iii) Distinguish between of SN² and SN¹ mechanism.

(iv) What happen when conc.HNO₃ is heated with 2,4,6-trinitrophenol.

(v) Write a note on Clemmensen reduction.

(vi) Write a note on By Hoffmann bromamide degradation.

(vii) How are vitamins classified depending upon their solubility?

(viii) How is nylon-6, 6 prepared?

Q.7. Answer any THREE of the following.                                                                                                              [09]

(i) Q. What are detergents? What are the types of detergent?  

(ii) Explain the mechanism of SN² reaction with energy profile diagram.

(iii) (a) What are Actinoids? Write their position in the periodic table?

       (b) Distinguish between Lanthanoids and Actinoids.

(iv) Discuss the classification of ligands.

Q. 8. Answer any ONE of the following.                                                                                                                [07]

(i) (a) How is nylon-6 prepared? Give its uses?

    (b) Explain the optical activity of Lactic acid.

    (c) Why does p-nitrochlorobenzene undergo displacement reaction readily with attack of nucleophile  

          OH^- ion.

(ii) (a) Write the structures of nucleoside and nucleotide?

      (b) How will you prepare pinacol from acetone.

      (c) How will you prepare aryl fluoride from diazonium salt.

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