CLASS XI

SAMPLE PAPER - 1

General Instructions:

(i) All the questions are compulsory.

(ii) Questions 1 to 4, carry one mark each and questions 5 and 6, carry 2 marks.

(iii) Questions 7 to 10 are short answer questions carrying one mark each.

(iv) Questions 11 to 15 are also short answer questions carrying two marks each.

(v) Questions 16 to 24 are also short answer questions carrying three marks each.

(vi) Questions 25 to 27 are assertion- reason questions carry two marks each.

(vii) Questions 28 to 30 are long answer questions and carry five marks each.

(viii) Use log tables for calculations if necessary.

 

Question 1:

The molar mass in grams is numerically equal to __________ in u.

1) Atomic mass

2) Formula mass

3) Molecular mass

4) All of the above                                                                                      

 

Question 2:

pH of the solution of salt of weak acid & strong base is given by

1) pH = 7 + ½ (pK_a - pK_b)

2) pH = 7 + ½ (pK_a + logC)

3) pH = 7 - ½ (pK_b + logC)

4) None of the above                                                                                

 

Question 3:

Which of following decomposes on heating to give Metal Oxide, NO₂ & O₂?

1) KNO₃

2) CsNO₃

3) NaNO₃

4) LiNO₃                                                                                                                           

 

Question 4:

The compound with highest boiling point is

1) n-hexane

2) n-pentane

3) 2,2-dimethyl propane

4) 2-methylbutane                                                                                     

 

Question 5:

In which of the following pairs, the ions are iso-electronic?

1) Al³⁺, N^3-

2) Mg³⁺, O^2-

3) F^-, Mg⁺

4) O^2-, Na⁺                                                                                                     

 

Question 6:

Electrophiles are electron seeking species. Which of the following sets consist of electrophiles only.

(i) BF₃, NH₃, H₂O

(ii) AlCl₃, SO₃, ⁺NO₂

(iii) ⁺NO₂, ⁺CH₃, CH₃ – ⁺C = O

(iv) ^-C₂H₅, ^.C₂H₅, ⁺C₂H₅                                                                                

 

Question 7:

Which element do you think would have been named by

(i) Lawrence Berkeley laboratory

(ii) Seaborg’s group                                                                                   

 

Question 8:

Why are potassium and caesium, rather than Lithium used in photoelectric cells?          

 

Question 9:

Write the chemical equation for the combustion reaction of butane.                      

 

Question 10:

Why COD is preferred over BOD?                                                         

 

Question 11:

Write the total number of sigma & pi bonds in the following molecules?

(a) C₂H₂

(b) C₂H₄                                                                                                          

 

Question 12:

A vessel of 120ml capacity contains a certain amount of gas at 35°C and 1.2 bar pressure. The gas is transferred to another vessel of volume 180ml at 35°C. What would be its pressure?   

 

Question 13:

Classify the following species into Lewis acids & Lewis bases and show how these act as such:

(a) HO^-

(b) F^-

(c) H⁺

(d) BCl₃                                                                                                             

 

Question 14:

Calculate the oxidation number of phosphorus in the following species.

1) PH₃

2) H₂PO₂^-                                                                                                       

 

Question 15:

Give 2 reactions showing that heavy water is used for the preparation of other deuterium compounds.                                                                                                 

 

Question 16:

Write the favourable factors for the formation of ionic bond.     

 

Question 17:

At what temperature will the root mean square velocity of SO₂ be same as that of methane at 300 K?                                                                                                           

 

Question 18:

The ionization constant of HF, HCOOH and HCN at 298K are 6.8 x 10^-4, 1.8 x 10^-4 and 4.8 x 10^-9 respectively. Calculate the ionization constants of the corresponding conjugate base.              

 

Question 19:

Write balanced chemical equation for the following reaction: Permanganate ion (MnO₄^–) reacts with sulphur dioxide gas in acidic medium to produce Mn²⁺ and hydrogensulphate ion. (Balance by oxidation number method)                                                                     

 

Question 20:

i) How will you prepare H₂O₂ from BaO₂?                                                            

ii) Statues coated with white lead on long exposure to atmosphere turns black and the original colour can be restored on treatment with H₂O₂. Explain.                    

 

Question 21:

i) How is Plaster of Paris prepared?                                                            

ii) Write the reaction of preparation of 

(a) BeCl₂ from BeO.

(b) BeH₂ from BeCl₂                                                                                          

 

Question 22:

i) How alkene can be obtained from vicinal dihalides?                         

ii) Prepare Deuteropropane from isopropyl bromide                           

iii) How is ethyne prepared on industrial scale from Calcium carbide?                    

 

Question 23:

i) Calculate the wavelength of radiation in nanometer having frequency 5.89 × 10¹⁴ Hz. Which part of the electromagnetic spectrum does it belong to?                     

ii) Which of the following orbitals are degenerate?

5d_xz, 4d_xy, 4d_yz, 5d_yz, 5d_xy                                                                          

 

Question 24:

i) Why 4f- & 5f-inner transition series of elements placed separately in periodic table?                                                                                                                  

ii) Write the name & symbol according to IUPAC nomenclature for the element with atomic number 115?                                                                             

iii) Write the general outer electronic configuration of d-block & f-block elements.                                                                                                            

 

Question 25:

Assertion (A): The first ionization enthalpy of alkali metals decreases down the group. Reason (R): Increase in number of orbitals increases the shielding effect which outweighs the increasing nuclear charge, therefore, the removal of outermost electron requires less energy on moving down the group.

(i) A and R both are correct but R is not the explanation of A.

(ii) A is false but R is correct.

(iii) A and R both are correct and R is the correct explanation of A.

(iv) A and R both are incorrect.                                                                                            

 

Question 26:

Assertion (A): Nitration of benzene requires the use of concentrated sulphuric acid and nitric acid.

Reason (R): The mixture of acids produces the electrophile for the reaction.

(i) A and R both are correct but R is not the explanation of A.

(ii) A is false but R is correct.

(iii) A and R both are correct and R is the correct explanation of A.

(iv) A and R both are incorrect.                                                                                

 

Question 27:

Assertion (A): Ozone is destroyed by solar radiations in upper stratosphere.

Reason (R): Thinning of ozone layer allows excessive UV radiations to reach the surface of earth.

(i) A and R both are correct but R is not the explanation of A.

(ii) A is false but R is correct.

(iii) A and R both are correct and R is the correct explanation of A.

(iv) A and R both are incorrect.                                                                                            

 

Question 28:

(a) Classify the following oxides as neutral, acidic, basic or amphoteric:

CO, B₂O₃, CO₂, Al₂O₃, Tl₂O₃                                                                            

(b) Write suitable chemical equations to show their nature.               

 

Question 29:

(i) Define the following:

(a) Lattice enthalpy

(b) First law of thermodynamics                                                                  

(ii) Find out whether it is possible to reduce MgO using carbon at 298K. If not, at what temperature it becomes spontaneous. For reaction

MgO(s) + C(s)                 Mg(s) + CO(g)

Δ_rH⁰ = 491.18 kJ/mol, Δ_rS⁰ = 197.67 J/K mol                                                        

 

Question 30:

a) Will CCl₄ give white precipitate of AgCl on heating it with silver nitrate? Give reason for your answer.                                                                                                                                                                                             b) Why is a solution of potassium hydroxide used to absorb CO₂ evolved during the estimation of carbon present in an organic compound?                                     

c) Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens?                                                                                                                         

d) Write the IUPAC name of the following compound:

                                                                          

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