CLASS XI

CHEMISTRY

SAMPLE PAPER-04

 

Max. Marks – 70                                                                                                                 Time allowed: 3 hours

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:

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

1) KNO₃

2) CsNO₃

3) NaNO₃

4) LiNO₃

 

Question 2:

The number of radial nodes for 4p orbital is __________.

(i) 3

(ii) 4

(iii) 2

(iv) 1

 

Question 3:

The number of sigma & pi bonds in 1-butene-3-yne are

a) 5 sigma; 5 pi

b) 7 sigma; 3 pi

c) 8 sigma; 2 pi

d) 6 sigma; 4 pi

 

Question 4:

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 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:

Which of the following statement(s) is/are not true about the following decomposition reaction?

2KClO₃ → 2KCl + 3O₂

(i) Potassium is undergoing oxidation

(ii) Chlorine is undergoing reduction

(iii) Oxygen is oxidised

(iv) None of the species are undergoing oxidation or reduction

 

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:

What is the oxidation state of K in KO₂?

 

Question 10:

Why does rain water have a pH of about 5 – 6?

 

Question 11:

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

 

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:

Carbon monoxide gas is more poisonous than the carbon dioxide gas. Why?

 

Question 14:

Using stock notation represent the following compounds:

1) V₂O₅

2) Cu₂O.

 

Question 15:

Write the IUPAC names of the following compounds:

1) (CH₃)₃CCH₂C(CH₃)₃  

2) (CH₃)₂C(C₂H₅)₂

 

Question 16:

a) Wooden ball of 200 g does not move like a wave when it is thrown at a speed of 200 km/h. Calculate the wavelength of the wooden ball and explain why it does not show wave nature.

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

 

Question 17:

Write the favourable factors for the formation of ionic bond.           

 

Question 18:

a) Give similarities in properties between Beryllium & Aluminium.

b) How is Sodium hydrogencarbonate prepared?

 

Question 19:

What are the reasons for the different chemical behaviour of the first member of a group of elements in the s- and p-blocks compared to that of the subsequent members in the same group?

 

Question 20:

a) Write the empirical formulae of the following:

1) C₆H₆

2) C₆H₁₂O₆

b) Density of water at room temperature is 1.0 g/cm³. How many molecules are there in one drop of water if its volume is 0.1 cm³?

c) State Gay Lussac’s Law of Gaseous Volumes.

 

Question 21:

Write balanced chemical equation for the following reaction: Reaction of liquid hydrazine (N₂H₄) with chlorate ion (ClO₃^–) in basic medium produces nitric oxide gas and chloride ion in gaseous state. (Balance by ion electron method)

 

Question 22:

a) A balloon of diameter 20 m weighs 100 kg. Calculate its payload if it is filled with He at 1.0 atm and 27 °C. Density of air is 1.2 kg m^-3. (R = 0.082 dm³ atm K^-1 mol^-1)

b) A gas occupies 20 L under a pressure of 1 atm. What will be its volume if the pressure is increased to 2 atm? (Temperature is constant)

 

Question 23:

a) Why gypsum is added during of setting of cement?

b) What is cement clinker?

c) How is Plaster of Paris prepared?

 

Question 24:

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 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): Some metals like platinum and palladium, can be used as storage media for hydrogen.

Reason (R): Platinum and palladium can absorb large volumes of hydrogen.

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

(ii) A is correct but R is not correct.

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

(iv) A and R both are false.

 

Question 27:

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 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:

(a) Define the following:

1) Spontaneous process

2) First Law of Thermodynamics

3) State functions

(b) For the following reaction:

H₂(g) + ½ O₂(g) → H₂O(l); Δ_fH^ɵ = -286 kJ/mol; Temperature = 298 K.

Calculate ΔS in surroundings.

 

Question 30:

Draw the structures of following compounds whose IUPAC names are given below:

1) 3-Ethyl-5-methylheptane

2) 3-Ethyl-1,1-dimethylcyclohexane

3) Cyclohexene

4) Hexane-2,4-dione

5) 5-Oxohexanoic acid

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