We present a mock paper prepared by Neha Kaushal, pgt chemistry, GD Salwan Public School, Delhi

General Instructions

I. All questions are compulsory.

II. Q.1to 5 are very short answer questions and carries 1 mark each.

III. Q.6 to 10 are short answer questions and carries 2 marks each.

IV. Q.11 to 22 are also short answer questions and carries 3 marks each.

V. Q.23 is a value based question and carries 4 marks.

VI. Q.24 to 26 are long answer questions and carries 5 marks each.

VII. Use of calculators is not allowed in the paper.

1. Aluminium metal can't be produced by the electrolysis of aqueous solution of Aluminium salt?

2. Name the electrolyte used in mercury cell?

3. Why SO3 is not absorbed directly in water to form H2SO4? 

4. Fresh tomatoes are a better source of vitamin-C than those present in tomatoes which have been stored for some time. Why?

5. Arrange in order of reactivity of SN2 mechanism: 

2-Bromo-2-methylpentane, 1-Bromopentane, 

2-Bromopentane 

6. (a) Zinc Oxide becomes yellow on heating. Comment. 

(b) Which type of point defect is produced when AgCl is doped with CdCl2?

7. An element has a bcc structure with a cell edge of 288 pm.  The density of the element is 7.2 g/cm3.  How many atoms are present is 208 g of element? 

8. Give Reasons:- 

(a) People suffer from disease called anoxia at higher altitudes. 

(b) When mercuric iodide is added to an aqueous solution of KI, freezing point decreases. 

9. Draw a structure for: 

(a) Peroxodisulphuric acid  (b) XeOF4

10. Complete:

(a) Cr2O72- + H2S + H+  ___›                            

(b) MnO4- + I- + H+ ___›

OR

(a) Oxidation of S2O32- by MnO4- is neutral medium.

(b) Oxidation of SO2 by Cr2O72- in acidic medium.

11. 2g of benzoic acid (C6H5COOH) is dissolved in 25g of benzene shows a depression in freezing point equals to 1.62 K. What is the percentage association of acid if it forms dimer in the solution . (Given that: Kf = 4.9Kkgmol-1) 

12. The molar conductivity of 0.025mol methanoic acid is 46.1 Scm2mol-1. Calculate the degree of dissociation and dissociation constant. Given ^m (H+) = 349.6 Scm2mol-1 and  0 (HCOO-) = 54.6 Scm2mol-1.

13. Write the reactions involved in extraction of iron in the blast furnace.

OR

Explain: 

(i) use of pine oil in froath floatation process. 

 (ii) conversion of sulphide ores into oxide before reduction is required.

(iii) use of silica in extraction of copper.

14. State:-

(a) Why E0 value for Mn & Ni are more negative than expected? 

(b) La(OH)3 is more basic than Lu (OH)3.

(c) Transition elements are good complexing agent.

15. (a) Give IUPAC name of [Cr(OH)4(H2O)2]-2

(b) Why [Ni(CO)4] posses tetrahedral geometry while [Ni (CN)4]2- is square planar?

16. (a) How aspirin helps in prevention of heart attack? 

(b) Why bithional is added to soaps?

(c) State use of equanil.

17. (a) Differentiate between pair of polymers on the basis of structure- Novolac & Bakelite         

(b) Name the polymer used to make non-stick kitchen wares.                  

(c) Give monomers of glyptal. 

18. (a) What happens to the structure of proteins on denaturation?  

(b) How can we say D(+) glucose contains five hydroxyl group?

(c) Name the vitamin whose deficiency is responsible for poor blood coagulation?

19. Write the mechanism involved in the formation of ether.

20. Distinguish between: 

(a) Benzyl chloride and chlorobenzene 

(b) Dimethylamine and aniline 

(c) Benzaldehyde and ethanal 

21. (a) Give IUPAC name of- 

CH3CH2CH(OH)CH(F)CH2COOH 

(b) Carry out the conversions: 

(i) Benzyl alcohol to 2-Phenylethanoic acid                     

(ii) Aniline to p-Bromoaniline

22. State the reason for: 

(a) Vinyl chloride less reactive than ethylchloride. 

(b) Hydrazones of aldehydes and ketones are not prepared in highly acidic medium. 

(c) Treatment of alkyl chloride with aqueous KOH leads to formation of alcohols while in presence of alcoholic KOH, alkenes are the major product. 

23. Most of the substance we come across in our daily life are colloids.  The meals we eat, the clothes we wear, the wooden furniture we use, the houses we live in, the newspaper we read, are largely composed of colloids.  Dust particles in air, smoke, milk and blood are also examples of colloidal solution.

(a) Why is the sky blue in colour?

(b) How can we stop bleeding?

(c) How are deltas formed?

(d) Why should we decrease SPM (Suspended Particulate Matter) in atmosphere?

24. (a) A certain reaction is 50% complete in 20 minutes at 300 K and the same reaction is again 50% complete in  5 mins at 350 K.  Calculate the activation energy if it is a first order reaction. [log4 = 0.602]

(b) State the condition in which bimolecular reaction is kinetically first order reaction.

(c) Draw a graph showing variation of concentration with time for a zero order reaction.

OR

(a) For the decomposition of azoisopropane{(CH3)2CHN=NCH(CH3)2} to hexane and nitrogen at 543 K , the following data are obtained:

t (s) R (mm of Hg)

0 35.0

360 54.0

720 63.0

Calculate the rate of constant.

(b) State the effect of temperature on the rate of constant of reaction?

(c) State the equation by which temperature effect on rate constant be represented quantatively. 

25. (a) A compound 'A' (C2H4O) on oxidation gives B (C2H4O2).  'A' undergoes Iodoform reaction. On   

treatment with HCN, 'A' forms a product 'C' which on hydrolysis gives 2-hydroxy propanoic acid.

(i) Write down the structures of A, B and C

(ii) Name the product when 'A' react with dil NaOH.

 (iii) Write down the equations for the reactions involved. 

(b) Account for- 

(i) Riemer-Tieman Reaction  (ii) Aldol Condensation

OR

(a) An organic compound with molecular formula C9H10O forms 2, 4-DNP derivative, reduces Tollen's reagent and undergoes Cannizzaro reaction. On vigourous oxidation, it given Bezene-1,2-dicarboxylic acid. Identify the compound and write the reactions involved.

(b) Account for:

(i) Kolbe's Reaction   (ii) HVZ Reation

26. (a) Account for:- 

(i) H3PO3 is dibasic in nature. 

(ii) PCl5 exists as ionic solid.

(i) HF is stored in wax coated glass bottles.

(b) Complete- 

(i) (NH4)2Cr2O7  ___›         

(ii) Cu + HNO3(conc) ___› 

OR

(a) Account for:- 

(i) Noble gases have larger atomic radii than other elements.

(ii) Bond angle of NH3 is higher than PH3.

(iii) H2S acts only as reducing agent while SO2 acts as both oxidising & reducing agent.

(b) Complete:-

(i) P4+NaOH+ H2O  ___› 

(ii) NH3+Cl2 (excess)  ___› 

Mock Test paper CHEMISTRY Class XII Total Marks 70