* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Class XI Chemistry Practics Paper
Water splitting wikipedia , lookup
Chemical equilibrium wikipedia , lookup
Rate equation wikipedia , lookup
Atomic theory wikipedia , lookup
Transition state theory wikipedia , lookup
Hydrogen bond wikipedia , lookup
Photoredox catalysis wikipedia , lookup
Chemical reaction wikipedia , lookup
Nucleophilic acyl substitution wikipedia , lookup
Acid dissociation constant wikipedia , lookup
Physical organic chemistry wikipedia , lookup
Resonance (chemistry) wikipedia , lookup
Acid–base reaction wikipedia , lookup
Click chemistry wikipedia , lookup
Biochemistry wikipedia , lookup
Hypervalent molecule wikipedia , lookup
Stoichiometry wikipedia , lookup
Metalloprotein wikipedia , lookup
Hydrogen-bond catalysis wikipedia , lookup
Lewis acid catalysis wikipedia , lookup
Bioorthogonal chemistry wikipedia , lookup
Electrolysis of water wikipedia , lookup
Hydroformylation wikipedia , lookup
SAMPLE PAPER-1 CLASS XI CHEMISTRY Time: 3 Hours General Instructions: All questions are compulsory. Marks of each question are indicated against it. Question nos. 1 to 8 are very short answer questions and carry 1 mark each. Question nos. 9 to 18 are short answer questions and carry 2 marks each. Question nos. 19 to 27 also short answer questions and carry 3 marks each. Question nos. 28 to 30 are long answer question and carry 5 marks each. Use log tables if necessary, use of calculators is not allowed. Maximum Marks: 70 Q1 How are 0.50 mol Na 2CO3 and 0.50 M Na2CO3 different? Q2 How many subshells are present in M shell? Q3 Which property of element is used to classify them in long form of periodic table? Q4 Write resonance structure of Ozone or sulphurdioxide. Q5 Write conjugate base for water and NH4+ species. Q6 What do you understand by Hydrogen economy? Q7 Find out oxidation number of chromium in K2Cr2O7 molecule Q8 Indicate sigma and pie bonds in CH2=C=CH2. 1 X 8 = 8 Marks Q9 Calculate number of photons with a wavelength of 3000pm that provides 1 Joule of energy.2 Marks Q10 Explain why bond angle in NH3 is more than in H2O molecule though both have sp3 hybridization. 2 MarksQ11 At constant temperature if the pressure of a fixed mass of gas is doubled what happens to its volume ? Which law governs this behavior of gases? 2 Marks Q12 How many grams of oxygen is required for complete combustion of 29g of butane as per the equation C4H10+4.5O22CO2+5H2O 2 Marks Q13 Calculate bond order of oxygen molecule. List all the information provided by the bond about this molecule.2 MarksQ14 Calculate the total pressure in a mixture of 16 g of oxygen and 4g of Hydrogen confined in a vessel of 1dm-3 at 27 degree celsius. (Molar mass of oxygen 32 Hydrogen 2 R= 0.083bar dm3 K-1mol-1) 2 Marks Q15 Balance following equation in acidic medium showing all steps, Br2 + H2O2- BrO2 + H2O 2 Marks Q16How are silicones prepared? Write necessary reaction. Write two uses of silicones. 2 marks Q 17 What is demineralised water? How is it obtained? 2 Marks Q18 What is the reason of diagonal relationship of elements? Write two properties of any two diagonally related elements. Or Give reasons (1) why alkali metals when dissolved in Liquid ammonia give blue solution? (2)Beryllium and Magnesium do not impart colour to the flame while other members do. Q19 (1) State Heisenberg s Uncertainty principle. (2) Write electronic configuration of Cu metal (Z=29) and Cr3+ ion. (3)Which orbital is represented by n=4 and l=3? 3 Marks Q20 Explain why (1) Halogens act as good oxidizing reagent. (2)Electron gain enthalpy of inert gases is zero. (3)Ionization enthalpy of Mg is higher than that of Na. 3 Marks Q21 (1) What do you mean by Bond Enthalpy? (2) Calculate bond enthalpy of Cl---Cl bond from following data. CH4(g) + Cl2 (g)--CH3Cl(g) +HCl (g) ΔH-= --109.3kJ mol-1 Bond enthalpy of C—H Bond = 413kJ, C—Cl Bond =326 kJ and H—Cl Bond =431kJ mol -1 3 Marks Q22 (1) What are extensive properties? (2) Write Gibbs free energy equation giving meaning of each term used. (3) Under what condition Δ U= ΔH ? 3 Marks Q23Write chemical equation only for preparation of (1) Plaster of Paris (2) Quick lime (3) slaked lime. 3 Marks Q24 (1) What do you mean by functional isomerism?3 Marks (2) What are electrophiles? (3) What is inductive effect ? Give an example. Or (1) Write IUPAC names for C6H5CH2CHO and (CH3)2—CH(NH2)—CH3 (2) Write an example of geometrical isomerism. (3) What do you mean by electromeric effect? 3 Marks Q25(1) Draw eclipsed and staggered conformations of ethane. (2)Write one equation each to show Wurtz reaction and Friedal craft alkylation. 3 Marks Q26 (1) How nitrogen is detected in an organic compound.?Wrirenecessary reactions. (2) How a molecular formula is different from empirical formula? 3 Marks Q27 (1) What do you mean by green chemistry? (2) Explain terms BOD and COD with reference to environmental chemistry. 3 Marks Q28 (1) For the reaction N2(g) + 3H2 (g)↔2NH3(g) the value of Kp is 3.6 x102-+ 2-2 at 500 K. Calculate the value of Kc for the reaction at the same temperature. R=0.083 bar L K-1 mol-1. (2) What do you understand by (1) Common ion effect (2) Buffer solution.3+2 Marks Or For the reaction PCl5↔PCl3+Cl2 at 473K the value of equilibrium constant Kc is 8.3 x10 -3 (1) Write an expression for Kc (2)What is the value of Kc for reverse reaction at same temperature. (3) What would be effect on Kc if pressure is increased. (2) State Henry’s Law. Write pH value of 1x10-5 M HCl solution. 3+2 Marks Q29 Give reasons for (1)[SiF62]- is known whereas [SiCl6]-2 is not known. (2) Diamond is a covalent solid, yet it has highest Melting Point. (3) Boric acid is considered a weak base. (4) BF3 behaves as Levis acid. (5) CO2 is a gas while SiO2 is a solid at room temperature. Or (1) What are fullerenes?-(2) Why is boric acid monobasic?(3)What is inert pair effect? (4)Why is PbCl2 is a good oxidizing reagent? (5)Write the formula of inorganic benzene. Q30 (1) State Markovnicoff’s rule.Using this write the reaction of propene with HCl. (2) Carry out following conversions (1) Ethyl alcohol to ethane. (2) Sodium acetanilide to benzene. (3) Benzene to nitrobenzene. 2+3 Marks Or (1) Write two reactions to show acidic nature of ethyne (2) Complete the following reactionsozone/Zn/H2O (1) CH3—CH=CH2 aquous KMnO4 (2)CH3—CH=CH2 (3)CH=CH + Br2 water SAMPLE PAPER-2 Class XI Time: 3 hours M.M-70 General instructions: 1. All questions are compulsory 2. Marks for each question are indicated against each 3. Question nos. 1-8 are very short answer questions and carry one mark each. Answer these questions in one word or about one sentence each. 4. Question nos. 9-18 are short answer questions and carry 2 marks each. Answer these questions in about 30 words each. 5. Question nos. 19-27 are short answer questions and carry 3 marks each. Answer these questions in about 40 words each. 6. Question nos. 28-30 are long answer questions and carry 5 marks each. Answer these questions in about 70 words each. 7. Use log table if necessary, use of calculators is not allowed. Q1 What does a mole represent? Q2 Why 4s orbital is filled earlier to 3d orbital? Q3.Locate the position of element with atomic number 33. Q4. Define Charles law. Q5.What is the entropy change when a liquid vaporizes? Q6.What is the conjugate acid of NH3? Q7.Which out of the two- lithium or sodium forms nitrides? Q8.What effect does branching of an alkane has on its boiling point? Q9.How many grams of NaOH should be dissolved to make 100 ml of 0.15 M NaOH solution? Q10.(a.) why Rutherford’s model was discarded?(b.) write the electronic configuration of S 2Q11.The reaction of NH2 CN(s) with oxygen was affected in a bomb calorimeter and ∆U was found to be -742.7 Kj/mol of cyanamide at 298 K. calculate enthalpy change for the reaction NH2CN(s)+3/2 O2 (g) N2 (g) + CO2 (g)+H2O(l) OR Calculate the enthalpy change for the reaction:-H2 (g) +Cl2 (g) 2HCl (g) Given that bond energies H-H, Cl-Cl and H-Cl bonds are 433,244 and 431Kj/mol respectively Q12.Write the equilibrium constant for the reaction :(a) (b) Cu(NO3)2 (s) Fe3+(aq) + 30H- (aq)Fe(OH)3 s 2CuO (s) + 4NO2(g) + O2 (g) Q13.Why is Li2CO3 decomposed at a lower temperature whereas Na2CO3 is decomposed at a higher temperature? Q14.Acount for the following.- (i) Na and K impart colour to the flame but Mg does not. (ii) Lithium is the best reducing agent in aqueous solution? Q15.(a) What is inert pair effect? Give one example. (b) Why is CO2 gas whereas SiO2 is solid? Q16.(a) Which of the following carboanion is more stable? (I) (CH3)3CCH2Ɵ (ii) CH3CƟHCH2CH3 (iii) CH3CH2CH2Ɵ (b) Draw the resonating structures for SO3. Q17.Explain the following(a)CCl4 does not give white precipitate with silver nitrate solution on heating. Why? (b) Why is O2NCH2O- is expected to be more stable than CH3CH2OQ18.complete the following(a)CH3Br + Mg Q19.The kinetic energy of an electron is 4.55x10 -25 J. dry ether the mass of electron (b) 2CH3CH2I + Na 9.1x10-31 Kg. dry ether Calculate velocity, momentum and the wavelength of the electron? 20.Give reasons: (a) Size of cation is always smaller than the parent atom. (b) Ionization enthalpy of nitrogen is greater than that of oxygen. (c) Electron gain enthalpies of beryllium and magnesium are positive. Q21.What will be the pressure exerted by mixture of 3.2 g of methane and 4.4 g of carbon dioxide contained in a 9 dm 3 flask of 27o C. Q22.What are factors responsible for spontaneity of reaction .Write in brief? Q23.The pH of 0.1 M solution of HCNOƟ is 2.34. Calculate the ionization constant for the acid and its degree of ionization in the solution. Q24. (a) Identify the substance oxidized and reduced: N2H4 + 2H2O2 N2 + 4H2O (c) Calculate the oxidization No. of Carbon in CH3CH2OH (d) Balance the following:MnO4–+Fe2+ Mn2++Fe3+(Acidic medium) OR .(a) Balance the following equation Fe2++Cr2O72- → Fe3++ Cr3+ (b) What is salt bridge. Write its application also Q25.(a) Give two properties of Water which are due to Hydrogen bonding. (b) Explain the Structure of H2O2. Q26.An org. compound contain 69% carbon and 4.8% Hydrogen, the remainder being oxygen, Calculate the masses of carbon dioxide and water produced when 0.20 g of this compound is subjected to complete combustion. Q27.(a) What do you mean by BOD? (b) Give difference between classical smog and photo chemical smog. Q28.Give reason: (a) Concentrated HNO3 can be transported in aluminium containers. (b) Graphite is used as lubricant. (c) A mixture if a dil. NaOH and aluminuim piece is used to open holes. (d) Carbon shows catenation but silicon does not. (e) Tin (II) is a reducing agent but Pb(II) is not. OR A certain salt(X) gives the following results (a) Its aqueous solution is alkaline to litmus. (b) It swells up to glassy material (Y) on strong heating. (c) When concentrated H2SO4 is added to hot solution of X, white crystals of an acid Z separates out. (d) Write equations for ii and iii. Also identify X, Y, Z. Q29.(a) i) How many sigma and Pi bonds are present in CH2=CH—C≡CH ii) Why H2+ is more stable than H2Ɵ? iii) Why is B2 molecule paramagnetic? (b)Discuss orbital structures of following molecules on the basis of hybridization i) BH3 ii) C2H2 OR a) on the basis of VSEPR theory explain shapes of following b) Which of the two NH3 or NF3 has higher dipole moment? c) Why N2 is more stable than O2? d) Why is ethyl alcohol miscible with water? (1) NH3 (2) H2O 30.a) Why terminal alkynes are acidic in nature? b) Write IUPAC name of followi CH3—C—CH2—COOH ║ O c) Write the following conversions i) Propene to 2-3 Dimethyl butaneii) Ethane to Ethyneiii) Benzene to Benzene sulphonic acid OR write short notes on (i)Wurtz reaction (ii)Markonikoff’s rule (iii)Freidel crafts alkylation (a)A hydrocarbon Y decolourizes bromine water. On ozonolysis it gives 3-methyl butanal and formaldehyde. Give the name and formula of the compound. (b)Why is benzene extraordinary stable though it contain 3 double bonds?