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Old Sunday, March 04, 2012
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Arrow Chemistry papers 2012

Chemistry Paper I

Q No.2.
(i) Glucose is formed according to the following reaction, absorbing 2840 kJ of heat. How much energy will be given out by combustion of 1.08 of glucose? (4)
6CO2(g)+ 6H2O(l)C6H12O6(s) + 6O2 (g)
(ii) State and explain the relationship of ionization energy of an atom with its reactivity.
(iii) Explain: Why dipole movement of BF3 is Zero?
(iv) Why dipole movement of NH3is greater than that of NF3?
(v) Why does SO2 have dipole movement while CO2 does not?

Q No.3.
(i) Differentiate between a gangue and slag. Give an example of a metallurgical step where slag, flux, and gangue are involved simultaneously.
(ii) Describe the different industrial process for preventing the metals from corrosion.
(iii) Draw diagram extraction of aluminum from soil.
(iv) Name the flux used in the extraction of Iron.

Q No.4.
(i) Given the reaction: XeF4(g) + F(g)XeF6(g) (04) Predict the change in hybridization and consequent, final shape of the molecule followed in the above reaction.
(ii) Valence shell electron pair repulsion theory can be used to predict the shapes of molecules. Using this theory explain the shapes acquired by BF3 and CH4.
(iii) Explain why HOH bond angle in H2O is slightly less than the tetrahedral angle 109.5?

Q No.5.
(i) A galvanic cell consists of metallic Zn place immersed in 0.1 M Zn (NO3)2 solution and metallic plate of lead in 0.02 M Pb (NO3)2 solution. Given EoZn2 + Zn = -0.76 V, EoPB2 + Pb = -0.13 V Write the half cell reaction.
(ii) Write the overall reaction of the cell.
(iii) Calculate the e.m.f. of the cell.
(iv) Explain the Nernst heat theorem.
(v) Define enthalpy of formation.

Q No.6. Write one reaction each for the preparation of the following, Also write one use of each product.
(i) Bleaching Power
(ii) Caustic Soda
(iii) Quick Lime
(iv) Ammonia
(v) How is caustic soda manufactured by using Nelson's cell?
(vi) What is an ideal solution?

Q No.7.
(i) What do you understand by entropy? In what way the total entropy change is related to spontaneity of a system and to a system in equilibrium.
(ii) Entropy change from liquid water to steam at 373 K is 109J mol−1 K-1. What the enthalpy change for the transition of liquid water to steam at 373 K?
(iii) Define Gibbs free energy function. Explain its significance.
(iv) Explain following:
(a) Ion selective electrode
(b) Quantum yield
(c) Fuel Cell
(d) Langmuir isotherm

Q No.8.
(i) Why is chlorination not the most desirable method of disinfecting polluted water?
(ii) What are anthropogenic pollutants? Give two examples each of primary and secondary pollutants.
(iii) What are the effects of detergents on fresh water bodies?
(iv) Calculate the pH of 0.001 M HCl solution.
(v) How Global Warming is caused? List and explain four consequences of green house effect.
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  #2  
Old Sunday, March 04, 2012
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Q No.2.
a. What is the difference between Valence Bond Theory and Molecular Orbital Theory? (8)
b. Draw the Molecular orbital Diagram of CO molecule showing sigma, pi bonding, non-bonding and anti bonding molecular orbital. (8)
c. Discuss the difference between the Hybridization of SO2 and SO3. (4)

Q No.3.
a. Discuss the rate law of SN1 mechanism. (6)
b. What is the importance of half life in the determination of order of reaction? (6)
c. What is the pseudo first order reaction? What is its importance? (8)

Q. No. 4
a. Describe the difference between physical adsorption and chemiadsorplion. (8)
b. The data of Langmuir for the adsorption of Nitrogen and mica at 90 K given

....... ............. P (atm) ....... ........... ..2.8 ..... 3.4 .....4.0 .....4.9 ....6.0 .....7.3 ......9.4 .....12.8..... 17.9..... 23.5
------------------------------------------------------------------------------------------------------------------
Amt adsorbed cumm at 20K & 760MM ... 12.3 ... 13.4 ... 15.1 ...17.9 ...19.0 ...21.6 ....23.9 .....25.5 .....28.2..... 30.8

Estimate the surface area of the mica sample in the Langnuir experiment? (8)
c. Define Homogeneous catalyst & Heterogeneous catalyst. (4)

Q. No. 5
a. Discuss stereo isomerism in compounds having 2 similar asymmetric carbon atoms. (6)
b. Draw Fischer projection formulae of the following compounds. (8)
i) R & S 2 - Bromopentane
ii) R & S 3 - chloro-1-pentane.
iii) R & S 3-chloro-3-methylocatne
iv) R & S 2-pentanol
c. What do you understand by the terms Z & E isomers? Illustrate your answer with example. (6)

Q. No. 6
a. Discuss the structure of Grignard Reagent. (4)
b. How these compounds can be prepared by Grignard Reagent? (12)
i) Ethane
ii) Acetic Acid
iii) 2-Butanol
c. What is the diazotization reaction? (4)

Q. No. 7
How would you prepare the following compounds from Benzene? Name each reaction as well. (20)
i) Acetophenone
ii) Bromobenzene
iii) Maleic anhydride
iv) Toluene
v) Benzaldehyde

Q. No. 8
a. Write main steps in the formation of following polymers: (3+3)
i) Nylon 6,6 and polyester by condensation polymerization
ii) Polyethlene by Free Radical polymerization
b. Differentiate between oil, fat & wax with examples. (9)
c. What are alkaloids? (5)
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Old Tuesday, March 06, 2012
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Well chemistry paper is going to be complicated every year. Q.Paper is set in such a way so that student could not attempt all section i.e a,b,c,d,e of the single Question. This is not an encouraging trend specially for the science subjects. 3 MCQs and 2,3 Questions were repeated unexpectedly from 2011's paper.
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Old Wednesday, March 07, 2012
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I think paper is that difficult that I expected .... As I have studied chemistry upto Intermediate level.... Due to deep interest in chemistry now I am opting for chemistry for 2013...
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Old Wednesday, March 07, 2012
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Quote:
Originally Posted by mfrehman1 View Post
I think paper is that difficult that I expected .... As I have studied chemistry upto Intermediate level.... Due to deep interest in chemistry now I am opting for chemistry for 2013...
I'll suggest you not to opt chemistry, its really time taking and day by day its level is being raised. Paper is unexpected and above all paper II is lethal. I m doing Ph.D in chemistry but I could,t solve the whole paper this year.
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Originally Posted by alimallah View Post
I'll suggest you not to opt chemistry, its really time taking and day by day its level is being raised. Paper is unexpected and above all paper II is lethal. I m doing Ph.D in chemistry but I could,t solve the whole paper this year.
In the above given paper what your were not able to solve ? Plz explain ..... I think all question are easily attempt able .... I will give chemistry 4 months ..... Insha allah
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Old Wednesday, March 07, 2012
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this is easy paper as compared to the previous year's..i didnt appeared this year but last year chemistry paper 1 was so much difficult..
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Old Friday, March 09, 2012
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Originally Posted by mfrehman1 View Post
In the above given paper what your were not able to solve ? Plz explain ..... I think all question are easily attempt able .... I will give chemistry 4 months ..... Insha allah
Well its easy to say from out the arena. Well if u feel then you can go ahead, it was only suggestion.

Quote:
Originally Posted by sumyra View Post
this is easy paper as compared to the previous year's..i didnt appeared this year but last year chemistry paper 1 was so much difficult..
Off course it was difficult as paper was not according to the trend of previous papers. Well I managed to take 116 in those papers. What was ur score in chemistry last year?
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Old Friday, March 09, 2012
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Paper was difficult or not??????? but its not in line with previous paper pattern.....especially Bonding of CO via MOT was not an easy thing.....atleast for a BSC level student

Its also the fact that reading the Paper in CSS - Forum and saying it was easy is very easy but being in the paper situation lets you feel a bit different pressure.......

Sumyra is very respected member of CSS-Chemistry. She has qualified chemistry. Best luck to her.

CO via MOT was harsh and i could not do it in paper......Sumyra can u plz let me know its bonding? plz
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Old Sunday, March 11, 2012
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Quote:
Originally Posted by Chintoo2010 View Post
Paper was difficult or not??????? but its not in line with previous paper pattern.....especially Bonding of CO via MOT was not an easy thing.....atleast for a BSC level student

Its also the fact that reading the Paper in CSS - Forum and saying it was easy is very easy but being in the paper situation lets you feel a bit different pressure.......

Sumyra is very respected member of CSS-Chemistry. She has qualified chemistry. Best luck to her.

CO via MOT was harsh and i could not do it in paper......Sumyra can u plz let me know its bonding? plz
i just read your post today and came to know that u have asked something from me..first of all thanx for appreciation..and secondly.. to say this question paper easy doesnt mean that we can attempt all the questions and it doesnt mean that i know each and every thing regarding chemistry.. i was just comparing this paper to the prvious year's because last year i was shocked to see the question paper .. i was able to attempt just 1 or 2 parts of each and every question in first paper...but this year chemistry first paper is a little bit different..atleast 4 required questions can be solved..
honestly speaking right now i dont know a b c of MOT it requires a lot of preparation and i always advise others not to opt chemistry.
i know the grievances of candidates opting chemistry because i am one of them
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