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Class XI Chemistry Practice Paper

Central Board of Secondary Education

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Time Allowed: 3 hours Maximum Marks: 70


General Instructions:

I) All questions are compulsory.

ii) Question number 1 to 8 are short answer questions and carry 1mark each.

iii) Question number 9 to 18 are short answer questions and carry 2 marks each.

iv) Question number 19 to 27 are also short answer questions and carry 3 marks each.

v) Question number 28 to 30 are long answer questions and carry 5 marks each.

vi) Use log tables if necessary

1. Write the electronic configuration of Fe3+ ion (Atomic number of Iron = 26).

2. Why does boron form electron deficient compounds?

3. Tertiary carbocation is more stable than Secondary. Explain why?

4. How does molarity change with temperature?

5. Write the IUPAC name of tertiary butyl alcohol.

6. An atomic orbital has l=2.What are the possible values of m?

7. Find out the oxidation number of manganese in MnO4 and MnO42-.

8. Carbon shows the property of catenation remarkably. Assign a reason for this statement.

9. Write any two points of differences between sigma and pi bond.


a) How many sigma and pi bond are present in the molecule:


b) Which type of hybrid orbital is used by the second carbon atom in the following molecule.


10. What is the density of SO2 gas at 27oC. (Atomic Weights: S=32, O=16, R=0.0821l/K/mol.

11. What happens when

a) Lead sulphide is reacted with hydrogen peroxide solution.

b) Chlorine reacts with milk of lime. Write chemical equations for reactions involved.

12. Why do real gases deviate from the ideal behaviour? What are the conditions under which real gases show ideal behaviour?

13. The mass of an electron is 9.1×10-31 Kg. If its kinetic energy is 3×10-25 J, calculate its wavelength.

14. Account for the following

a. The first ionization enthalpy of Mg is greater than that of Al.

b. Oxygen has a lower electron gain enthalpy than sulphur.

15. Calculate the bond order of O2+ and O22- molecular ions and predict their magnetic behaviour.

16. Explain the following:

a. Wurtz reaction

b. Huckles Rule

17. Account for the following :

a. Pentane has higher melting point than 2-methyl butane.

b. Ethyne is more acidic than ethane.

18. What are electrophiles and neucleophiles? Give one example of each.

19. Write the net ionic equation for the reaction of potassium dichromate(VI) with sodium sulphite in an acid solution to give chromium(III) ion and the sulphate ion.


Permanganate (VII) ion in basic solution oxidises iodide ion to produce iodine and manganese dioxide. Write a balanced ionic equation to represent this redox reaction.

20. Write short notes on :

a. Photochemical Smog

b. Ozone Hole

c. Acid Rain

21. a. How will you prepare hydrogen peroxide by industrial method.

b. What happens when

i. ionic hydrides are treated with water?

ii. Boron tri-fluoride reacts with sodium hydride?

22. a. Define the term conjugate acid-base pair.

b. The value of Kc for the reaction 2A↔B+C is 2×10 -3 at 500K at a given time. The composition if reaction mixture is [A]=[B]=[C]= 3×10-4 M. Is the reaction mixture at equilibrium? If not, what is the direction of net reaction?

23. State Le-Chatelier’s Principle. What are its applications in the manufacture of Ammonia in Habers Process?

24. How will you detect the presence of nitrogen in Lassaigne’s Test .

During estimation of nitrogen by kjeldahl’s method the ammonia evolved from 0.5g of the compound neutralised 10ml of 1M H2SO4.Find out the percentage of nitrogen in the compound.

25. Draw the structure of:

a. Di-borane


C.BeCl2 in solid state

26. a. What do you understand by common ion effect?

b. Determine the solubility of barium sulphate in 0.05M in barium chloride solution.(Ksp-BaSO4=1.1×10-10).

27. Why lithium shows anomalous behaviour in the group. Give two points of similarities between lithium and magnesium.

28. Explain the following with suitable examples:

a. Inductive Effect.

b. Resonance Effect.

c. Hyper-conjugation.


Define Isomerism. Explain the type of isomerism shown by

a. But-2-ene.

b. Conformations of Ethane.

29. a. SiF6 2- is known where as SiCl6 2- is not. Give possible reason.

b. Why is boric acid considered as a weak acid?

c. What are silicones?

d. CCl4 does not hydrolyse unlike SiCl4.

e. Tl(1) compounds are more stable than Al(1) compounds. Give reasons.


a. Why does BCl3 act as a Lewis acid?

b. What is dry-ice? Why is it so called?

c. What is water gas? How is it prepared?

d. Which is the basic building unit of all silicates?

e. What are zeolites?

30. How will you bring about the following conversions?

i. Propene to 1- bromo-propane.

ii. Benzene to acetophenone.

iii.Ethyne to acetaldenhyde.

iv.Ethene to formaldehyde.

v.Sodium Benzoate to Benzene.


What happens when

a. Ethyne gas is allowed to pass over red hot iron tube.

b. Calcium carbide is treated with water.

c. Propene is treated with dilute KMnO4.

d. Benzene is treated with chlorine in presence of UV light.

e. Phenol is treated with heated zinc dust.

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Class 12 CBSE Chemistry Test Paper


Blood cells collapse when suspended in saline water. Account for it.



Name any two neutral oxides.



a) What is the principle behind reverse osmosis?

b) Which substance is usually added into water in the car radiator to act as antifreeze?



State Raoult’s law for a solution containing non-volatile solute.




Complete the following equations and also balance them.

i) NH4Cl + Ca(OH)2 clip_image002

ii) Zn + HNO3 clip_image004

iii) P4 + SOCl2clip_image004[1]

iv) MnO4 + HClclip_image006



Draw the structures of the following compounds.

i) Peroxodisulphuric acid

ii) Phosphorous acid and account for the basicity of phosphorous acid.



45 g of ethylene glycol ( C2H6O2) is mixed with 600g of water. Calculate (a) the freezing point depression and (b) the freezing point of the solution.



2 g of benzoic acid (C6H5COOH) dissolved in 25 g of benzene shows a depression in freezing point equal to 1.62 K. Molal depression constant for benzene is 4.9 K Kgmol-1. What is the percentage association of acid if it forms dimer in solution?



Arrange the following in the order indicated.

i) MF, MCl, MBr, MI – Decreasing ionic character.

ii)HOCl, HOBr, HOI – increasing acidic strength

iii)NH3, AsH3, SbH3, PH3 – Decreasing bond dissociation enthalpy



Give reasons for the following observations.

i)Halogens are strong oxidizing agents

ii)Noble gases have large positive electron gain enthalpy.

iii)Sulphur shows paramagnetic character in vapour phase.



How do you prepare XeO3 from XeF4? Write equation. Draw the structure of XeF6. Mention any two applications of He gas.



i) How is O3 estimated quantitatively?

ii)H2SO4 is a moderately strong acid. Give evidence.

ii)Though N2 exhibits +5 oxidation state, it doesnot form pentahalide. Why?

iv)Mention the conditions required for the maximum yield of NH3.

v)What happens when Cl2 reacts with excess NH3 and NH3 reacts with excess Cl2. Give equations.



i) With the help of a graph explain positive deviation.

ii)The vapour pressure of pure liquids A & B are 450 & 700mm Hg respectively at 350K. Find out the composition of the liquid mixture if total vapour pressure is 600mm Hg. Also find the composition of the vapour phase.


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CBSE Class XI Chemistry Unit Test (First Term)


Express the following in the scientific notation:

a) 0.000456 b) 500.0



Name the experiment which is used to find the charge of an electron & what is the charge of an electron?



What are the drawbacks of Rutherford’s atomic model?



Round up the following up to three significant figures.

a) 46.216 b) 10.4107 c) 0.04597 d) 2808



Calculate the number of atoms in the following;

a) 52 moles of Ar b) 52g of He.



What is the SI unit of mass? How is it defined?



State law of multiple proportion with an example.



The density of 3M solution of NaCl is 1.25g/ml. Calculate molality of the solution.



Define isobars with examples.



Mention the two developments which played a major role in the formulation of Bohr’s model of an atom.



The atomic number and mass number of Calcium are 20 & 40 respectively. Find out the number of electrons, protons and neutrons in a Ca2+ ion.



a) How many seconds are there in 3 days?

b) A jug contains 5L of milk. Calculate the volume of milk in m3.



Calculate the concentration of HNO3 in moles per litre in a sample which has density 1.41g/ mL & the mass percent of nitric acid in it being 69%.



A compound contains 4.07% Hydrogen, 24.27 carbon and 71. 65% chlorine. Its molar mass is 98.96g. What is the empirical formula of the compound?



Write notes on Thomson’s plum pudding model of atom with its important features.



What are the conclusions drawn by Rutherford in his gold foil experiment?



i) Define limiting reagent.

ii) 50.0kg of N2 (g) and 10.0kg of H2 (g) are mixed to produce NH3 (g). Calculate the NH3(g)

produced. Identify the limiting reagent in this reaction.


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CBSE Chemistry Test Paper

1. Differentiate between ore and mineral? (1)

2. Nitrogen is inert compared to phosphorous why? (1)

3. Give an example of shape selective catalyst? (1)

4. What are aerosols give example. (1)

5. Why do Zr and Hf exhibit similar properties ? (1)

6. Assign a reason (2)

a)Ammonia is stronger base than phosphine

b)Catenation tendency of Sulphur is more than Oxygen . Read more…

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CBSE Chemistry Class 11 (Mid Term Exam Model Paper)


Duration: 3 hrs Maximum marks: 70

General Instructions:

All questions are compulsory.

i)Marks for each question are indicated against it.

ii)Question numbers 1 to 8 are very short answer questions and carry 1 mark each.

iii)Question numbers 9 to 18 are short answer questions and carry 2 marks each.

iv)Question numbers 1 9 to 27 are also short answer questions and carry 3 marks each.

v)Question numbers 28 to 30 are long answer questions and carry 5 marks each.

vi)Use logarithm tables if necessary. Use of calculator is not allowed.


1 Calculate the number of moles in 14g of N2 molecule. (1)
2 What would be the IUPAC and symbol for the elements with atomic numbers 121 and 113. (1)
3 Draw the Lewis dot structure of Nitrite ion (NO2). (1)
4 What do you meant by bond length? (1)
5 Define coefficient of viscosity. What is its S.I. unit? (1)
6 Calculate the oxidation number of phosphorous in H3P2O7and Au in HAuCl4. (1)
7 How the presence of H ions be confirmed in ionic hydrides? (1)
8 What do you understand by the term hydrogen economy ? (1)
9 Chlorine is prepared in the laboratory by treating MnO2 with aqueous HCl according to the reaction:

clip_image001[4]4HCl(aq) + MnO2 (s) 2H2O (l) + MnO2(aq) + Cl2(g)

How many grams of HCl react with 5.0 g of MnO2?


clip_image002[6]Calcium carbonate reacts with aqueous HCl to give CaCl2 and CO2 according to the reaction, CaCO3 (s) + 2HCl(aq) CaCl2 (aq) + CO2 (g) +H2O (l).

What mass of CaCO3 is required to react completely with 25ml of 0.75 M HCl?

Atomic mass of Mn=25,Ca=20 Read more…

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