सी.बी.एस.ई. रसायन विज्ञान-द्वितीय में सबसे महत्वपूर्ण प्रश्न पत्र - 2018 नमूना प्रश्न
1. Question no. 1 to 5 are very short answer questions, carrying 1 mark each.
2. Question no. 6 to 10 are very short answer, carrying 2 marks each.
3. Question no. 11 to 22 are short answer, carrying 3 marks each.
4. Question no. 23 is a value based question and carry 4 marks.
5. Question no. 24 to 26 are long answer of 5 marks each.
6. Calculators are not permitted. Use log tables if necessary.
SECTION A (1 Mark )
Q.1 Write the IUPAC name of the following organic compound. CH3-O-CH2-CH(OH)-CH2-CH3
Q.2 When a crystal of NaCl is heated in Na vapour it acquires a yellow Colour. This is due to which defect and write also name of centre which create?
Q.3 Which amongst the following is strongest oxidizing agent ClO4 -, BrO4-, IO4-
Q.4 p-Dichlorobenzene has higher m.p and solubility than ortho and meta isomer .why?
Q.5 C6H5NO2---- Fe/HCl ---- A --- NaNO2 + HCl ----- B ---- H2O/H + --- C Identify A,B,C.
SECTION B (2 Marks )
Q.6 State Raoult’s law for solutions of two volatile liquids. Taking suitable examples explain the meaning of positive and negative deviation from Raoult’s law.
Q.7 Calculate the amount of KCl which must be added to 100g of water so that water freezes at -2.0°C. Assume that KCl undergoes complete dissociation.
Q.8 What happens when D-Glucose is treated with the following reagents?
(ii) Bromine water.
Q.9 Account for the following:
(i) Aniline does not undergo friedel-crafts reaction.
(ii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
Explain the following with an example.
(a) Coupling reaction.
(b) Williamson synthesis.
Q.10 How will you bring about the following conversions in more than two steps?
(i) Propanone to Propene
(ii) Benzoic acid to Benzaldehyde.
SECTION C (3 Marks )
Q.11 Indicate the type of isomerism exhibited by the following complexes and draw the structures for these isomers:
Q.12 The resistance of a conductivity cell containing 0.001 M KCl solution at 298K is 1500 Ohms. What is the cell constant if conductivity of 0.001 M KCl solution at 298K is 0.146 x 10-3 S Cm-1.
Q.13 Describe the following
(i) Aldol condensation
(ii) cannizaro reaction
Q.14 Answers the following:-
(i) How much electricity in terms of Faraday is required to produce 50 g of Al from Al2O3?
(ii) A reaction is first order in A and second order in B. How is the rate affected when concentration of B is tripled?
(iii) Use valance bond theory predict the geometry and magnetic behaviour of [Co(NH3)6]+3 ion .[At.No. of Co = 27].
Q.15 15. Give one chemical test to distinguish:
(i) Acetaldehyde and Benzaldehyde
(ii) Benzophenone and Acetophenone
(iii) Ethyl amine and dimethylamine
Q.16 Write the Nernst equation. Calculate e.m.f of the following cell at 250C:
Pt(s)/Br2(l)/Br-(0.010M)//H+(0.030M)/H2 (1 bar)/Pt(s) [Given: Eo Br2/Br- = +1.08 V]
Q.17 Outline the principles of refining of metals by the following methods:
i) Zone refining
ii) Electrolytic refining
iii) Vapour phase refining.
Q.18 An organic compound with the molecular formula C9H10O forms 2,4-DNP derivative, reduces Tollen’s reagent and undergoes Cannizaro reaction. On vigorous oxidation, it gives 1, 2-benzene dicarboxylic acid. Identify the compound.
Q.19 Write the structure of monomer& uses each of BunaN, Teflon, Bakelite.
Q.20 (a) Differentiate between the thermoplastic and thermosetting polymers.
(b) What are biodegradable polymers? Give two examples.
State the function along with one example each of:
Q.21 N2 is bubbled through water at 293K .How many milli moles of N2 would dissolve in 1 lt of water. Assume that N2 exerts a partial pressure of .987 bar.Given that Henry law constant for N2 is 76.48 bar.
18 gm glucose is dissolved in 1Kg of water .At what temperature will water boil at 1.013 bar. Kb for water is .52 KKg / mole.
Q.22 Silver crystallises in fcc lattice. If edge length of the cell is 4.07 × 10-8cm and density is 10.5 g cm-8, calculate the atomic mass of silver.
Explain the terms : (i) Electrophoresis (ii) Coagulation (iii) Dialysis (iv) Tyndall effect
SECTION D (4 Marks )
Q.23 Raju was struggling from stomach ache because of hyper acidity condition. His friend, Ramesh offered him ‘Soda water’ (Aqueous NaHCO3), While Ratan wanted Raju to take ‘Gelusil’ (Aluminium hydroxide gel).
a) Should Raju follow Ramesh’s advice or Ratan’s?
b) What is the advantage of one medicine over the other?
c) What are the values associated with the three friends’ reactions?
SECTION E (5 Marks )
Q.24Answers the following:-
(i) Which of the compound in the pair will react faster in SN2 reaction with The aquous hydro oxide ion (CH3)3 C- Br Or CH3CH2Br.
(ii) What are the bases present in RNA- molecule ?
(iii) Why can not vitamin C be stored in our body ?
(iv) Show the preparation of ethylamine by Gabriel phthlamide reaction.
(v) Arrange the following in increasing order of their basic strength:
C2H5NH2, (C2H5)2NH, (C2H5)3N, C6H5NH2
Answers the following (Explain why):-
(a) Aldehydes are more reactive than Ketones towards Nucleophilic addition reaction
(b) There are two NH2 group in semicarbazide however only one is involved in the formation of semi carbazones.
(c) During the preparation of esters from a carboxylic acid and an alcohol in the presence of an acid catalyst, the water or the ester should be removed as fast as it is formed.
(d) Amino group in benzene ring is ortho-pera directing
(a)Draw the circuit diagram of a common emitter amplifier using an NPN transistor. What is the phase difference between input and output voltage ? Draw the input and output wave form,. Write an expression for its voltage gain. State two reasons Why a common emitter amplifier is preferred to a common base amplifier.
(b) The input resistance of a silicon transistor is 665 ohm. Its base current is changed by 15 micro amp which results in a change of 2 mA in the collector current. The transistor is used as a common emitter amplifier with a load resistance of 5 K Ohm. What is the voltage gain of the amplifier ?
(a) why PCl3 fumes in air?
(b) Why oxygen does not show +6 state?
(c) Why higher concentration of O3 are explosive?
(d) Why Cl2 act as bleaching agent?
(e) How is xenon oxide is prepared. Draw its structure?
(a) Why all the bonds in PCl5 are not of equal length?
(b) Why H2S is less acidic than H2Se ?
(c) How is O3 estimated quantitatively?
(d) Why fluorine has lower electron gain enthalpy than chlorine?
(e) What inspired N.Bartlett for carrying out reaction between Xe And PtF6 ?
Q.26Account for the following:
1. Zn, Cd and Hg are not considered as transition elements.
2. Scandium is a transition element but Zinc is not.
3. Silver atom has completely filled d orbital (4d10) in its ground state, yet it is transition element
4. Transition metals have high melting and boiling points.
5. Transition elements exhibit higher enthalpies of atomization.
(a) Describe how Potassium dichromate is made from chromite ore. Give the equations for the Chemical reactions involve.
(b) Write balanced ionic equations for reacting ions to represent the action of acidified Potassium dichromate solution on:
(i) Potassium iodide solution
[i] iron (ii) solution [iii] H2S