CHEMISTRY (Theory)

General Instructions :
(i) All questions are compulsory.
(ii) Questions number 1 to 5 are very short-answer questions and carry
1 mark each.
(iii) Questions number 6 to 10 are short-answer questions and carry 2 marks each.
(iv) Questions number 11 to 22 are also short-answer questions and carry
3 marks each.
(v) Question number 23 is a value based question and carries 4 marks.
(vi) Questions number 24 to 26 are long-answer questions and carry 5 marks each.
(vii) Use log tables, if necessary. Use of calculators is not allowed.

Q1.What is the formula of a compound in which the element P forms ccp lattice and atoms of Q occupy 2/3rd of tetrahedral voids ?

Q2.Arrange the following hydrides of Group-16 elements in the increasing
order of their thermal stability :
H2O, H2S, H2Se, H2Te

Q3.What is the role of desorption in the process of catalysis ?

Q4.Write the IUPAC name of the following compound :
C6H5– CH2– CH2– OH

Q5.Among the isomers of pentane (C5H12), write the one which on photochemical chlorination yields a single monochloride

Q6.Do the following conversions in not more than two steps :
(a) Propene to Acetone
(b) Propanoic acid to 2-hydroxypropanoic acid
                                   OR
Write the reaction involved in the following :
(a) Etard reaction
(b) Wolff-Kishner reduction

Q7.What are colligative properties ? Write the colligative property which is used to find the molecular mass of macromolecules.

Q8.a) Write the IUPAC name of the isomer of the following complex :[Pt(NH3)2Cl2]
(b) Write the formula for the following :
Tetraammineaquachloridocobalt(III) nitrate

Q9.In a galvanic cell, the following cell reaction occurs :
Zn (s) + 2 Ag+(aq) Zn2+ (aq) + 2 Ag (s)o cell E = + 1·56 V
(a) Is the direction of flow of electrons from zinc to silver or silver to zinc ?
(b) How will concentration of Zn2+ ions and Ag+ ions be affected when the cell functions ?

Q10.In the following ions :
Mn3+, V3+, Cr3+, Ti4+
(Atomic no. : Mn = 25, V = 23, Cr = 24, Ti = 22)
(a) Which ion is most stable in an aqueous solution ?
(b) Which ion is the strongest oxidizing agent ?
(c) Which ion is colourless ?
(d) Which ion has the highest number of unpaired electrons ?

Q11.The electrical resistance of a column of 0·05 M KOH solution of diameter 1 cm and length 45·5 cm is 4·55  103 ohm. Calculate its molar conductivity.

Q12.Define the following terms with an example in each :
(a) Lyophobic colloids
(b) Homogeneous catalysis
(c) O/W emulsion
                                            OR
Write three differences between Physisorption and Chemisorption.

Q13.A solution of glucose (Molar mass = 180 g mol–1) in water has a boilingpoint of 100·20C. Calculate the freezing point of the same solution. Molal constants for water Kf and Kb are 1·86 K kg mol–1 and 0·512 K kg mol–1
respectively.

Q14.(a) Write the principle of vapour phase refining.
(b) What is the role of depressant in froth floatation process ?
(c) Write the name of reducing agent to obtain iron from Fe2O3 at high temperature.

Q15.(a) What is the radius of sodium atom if it crystallises in bcc structure with the cell edge of 400 pm ?

(b) Examine the given defective crystal :

(i) Write the term used for this type of defect.
(ii) What is the result when XY crystal is doped with divalent(Z2+) impurity ?

Q16.Give reasons :
(a) Propanone is less reactive than ethanal towards nucleophilic addition reactions.
(b) O2N – CH2 – COOH has lower pKa value than CH3COOH.
(c) (CH3)2CH – CHO undergoes aldol condensation whereas(CH3)3C – CHO does not.

Q17.Write the names and structures of the monomers of the following
polymers :
(a) Terylene
(b) Teflon
(c) Nylon-6,6

Q18.(a) Define crystal field splitting energy. On the basis of crystal field
theory, write the electronic configuration for d4
ion if o< P.
(b) [Ni(CN)4]2– is colourless whereas [Ni(H2O)6]2+ is green. Why ?
(At. no. of Ni = 28)

Q19.What happens when
(a) (CH3)3C – OH is treated with Cu at 573 K,
(b) Anisole is treated with CH3Cl / anhydrous AlCl3
(c) Phenol is treated with Zn dust ?
Write chemical equations in support of your answer.

Q20.Draw the structures of the major monohalo product for each of the following reactions :

Q21.Account for the following :
(a) CuCl2 is more stable than Cu2Cl2
(b) Atomic radii of 4d and 5d series elements are nearly same.
(c) Hydrochloric acid is not used in permanganate titrations.

Q22.Define the following terms :
(a) Tranquilizer
(b) Anionic detergent
(c) Disinfectant

Q23.After watching a programme on TV about the presence of carcinogens(cancer causing agents) Potassium bromate and Potassium iodate in bread and other bakery products, Veena, a class XII student, decided to make others aware about the adverse effects of these carcinogens in foods. She consulted the school principal and requested him to instruct the canteen contractor to stop selling sandwiches, pizzas, burgers and other bakery products to the students. The principal took an immediate
action and instructed the canteen contractor to replace the bakery products with some proteins and vitamins-rich food like fruits, salads, sprouts, etc. The decision was welcomed by the parents and students.After reading the above passage, answer the following questions :
(a) What are the values (at least two) displayed by Veena ?
(b) Which polysaccharide component of carbohydrates is commonly present in bread ?
(c) Write the two types of secondary structures of proteins.
(d) Give two examples of water soluble vitamins.

Q24.(a) A first order reaction is 75% completed in 40 minutes. Calculate its t1/2.
(b) Predict the order of the reaction in the given plots :

where [R]o is the initial concentration of reactant.
(Given : log 2 = 0·3010, log 4 = 0·6021)

The following data were obtained for the reaction :
2 NO + O2 2 NO2

Q25.(a) Find the order of reaction with respect to NO and O2
(b) Write the rate law and overall order of reaction.
(c) Calculate the rate constant (k).

(a) Account for the following :
(i) BiH3 is the strongest reducing agent in Group 15 elements hydrides.
(ii) Cl2 acts as a bleaching agent.
(iii) Noble gases have very low boiling points.
(b) Draw the structures of the following :
(i) H4P2O7
(ii) XeOF4
                                         OR
(a) Although nitrogen and chlorine have nearly same electronegativity
yet nitrogen forms hydrogen bonding while chlorine does not. Why ?
(b) What happens when F2
reacts with water ?
(c) Write the name of the gas evolved when Ca3P2
is dissolved in
water.
(d) Write the formula of a noble gas species which is isostructural
with IBr^2- .
(e) Complete the equation :
[Fe(H2O)6]2+ + NO 

Q26.Write the structures of A, B, C, D and E in the following reactions :

                                                               OR
(a) Write the structures of the main products when benzene
diazonium chloride reacts with the following reagents :
(i) CuCN
(ii) CH3CH2OH
(iii) Cu / HCl
(b) Arrange the following in the increasing order of their basic
strength :
CH3NH2, (CH3)2NH, C6H5NH2, C6H5CH2NH2
(c) Write one chemical test to distinguish between Aniline and Ethyl amine.