CLASS XI

                                                                   CHEMISTRY

                                                            SAMPLE PAPER-2

 

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:

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

(i) 3

(ii) 4

(iii) 2

(iv) 1

 

Question 2:

Given below are few statements related to Mendeleev’s Periodic table:

a) Mendeleev ignored the order of atomic weights at some instances and placed the elements with similar properties together in same group.

b) He proposed that some of the elements were still undiscovered and therefore, left several gaps in the table.

c) Mendeleev arranged elements in horizontal rows and vertical columns of a table in order of their increasing atomic weights in such a way that the elements with similar properties occupied the same vertical column or group.

d) Mendeleev relied on the similarities in the empirical formulas and properties of the compounds formed by the elements.

Which of the above statement/statements are incorrect?

1) a

2) b

3) d

4) none of the above

 

Question 3:

Which of the following hydrides is electron-deficient hydride?

(i) B₂H₆

(ii) NH₃

(iii) H₂O

(iv) CH₄

 

Question 4:

Formula of Quick lime & Slaked lime is __________ & __________ respectively.

1) CaCO₃, Ca(OH)₂

2) CaO, Ca(OH)₂

3) Ca(OH)₂, CaO

4) CaO, CaCO₃

 

Question 5:

CO is isoelectronic with

(i) NO⁺

(ii) N₂

(iii) SnCl₂

(iv) NO₂^–

 

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:

What do you mean by Biochemical Oxygen Demand?

 

Question 8:

What is the oxidation state of K in KO₂?

 

Question 9:

Define: Standard Enthalpy of formation (Δ_fH^ɵ).

 

Question 10:

Assign the position of elements having outer electronic configuration

1) ns² np⁴ for n = 3

2) (n – 1)d² ns² for n = 4

 

Question 11:

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

 

Question 12:

Write the IUPAC names of the following compounds:

1) (CH₃)₃CCH₂C(CH₃)₃  

2) (CH₃)₂C(C₂H₅)₂

 

Question 13:

a) How many water molecules can directly attach to one water molecule through H-bonding?

b) Why is dihydrogen gas not preferred in balloons?

 

Question 14:

Using given standard electrode potentials, find out whether redox reaction between Fe³⁺

& Cu is feasible or not.

Standard electrode potential values: Fe³⁺/Fe²⁺ = +0.77 V; Cu²⁺/Cu = +0.34 V

 

Question 15:

a) The Balmer series in the hydrogen spectrum corresponds to the transition from n₁ = 2 to n₂ = 3,4,5, .......... This series lies in the visible region. Calculate the wave number of line associated with the transition in Balmer series when the electron moves to n = 5 orbit. (R_H = 109677 cm^–1)

b) What is black body & black body radiation?

 

Question 16:

a) How will you prepare propanone from propyne?

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

c) How alkene can be obtained from vicinal dihalides?

 

Question 17:

a) Give similarities in properties between Beryllium & Aluminium.

b) How is Sodium hydrogencarbonate prepared?

 

Question 18:

a) Melting point of compound showing intermolecular H-bonding is more or less than melting point of compound showing intramolecular H-bonding?

b) Draw the resonance structures of Ozone molecule.

c) What is octet rule?

 

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:

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 22:

a) The value of K_c for the reaction, N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g) is 0.50 at 400 °C. Find the value of K_p at 400 °C when concentrations are expressed in mol L^-1 and pressure in atmosphere.

b) For the hypothetical reactions, the equilibrium constant (K) values are given:

A ⇌ B; K₁ = 2;

B ⇌ C; K₂ = 4;

C ⇌ D; K₃ = 3

What is the equilibrium constant (K) for the reaction A ⇌ D?

c) The solubility of Sb₂S₃ in water is 1 x 10^-5 mol/L at 298 K. What will be its solubility product?

 

Question 23:

What is acid & base according to

1) Arrhenius theory

2) Bronsted-Lowry theory

3) Lewis Concept

 

Question 24:

a) Give any four physical properties of gases.

b) Write the reaction of preparation of BeH₂ from BeCl₂

 

Question 25:

Assertion (A): All isotopes of a given element show the same type of chemical behaviour. Reason (R): The chemical properties of an atom are controlled by the number of electrons in the atom.

(i) Both A and R are true and R is the correct explanation of A.

(ii) Both A and R are true but R is not the correct explanation of A.

(iii) A is true but R is false.

(iv) Both A and R are false.

 

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): The compound cyclooctane has the following structural formula:

It is cyclic and has conjugated 8π-electron system but it is not an aromatic compound.

Reason (R): (4n + 2) π electrons rule does not hold good and ring is not planar.

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

(ii) Both A and R are correct but R is not the correct explanation of A.

(iii) Both A and R are not correct.

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

 

Question 28:

(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 29:

Give reasons:

(a) Conc. HNO₃ can be transported in aluminium containers.

(b) A mixture of dil. NaOH and aluminium pieces is used to open drains.

(c) Graphite is used as Lubricant.

(d) Diamond is used as abrasive.

(e) Aluminium alloys are used to make aircraft body.

 

Question 30:

(a) What are electrophiles & nucleophiles? Explain with examples.

(b) Identify the reagents shown in bold in the following equations as nucleophiles or electrophiles:

1) CH₃COOH + OH^- → CH₃COO^- + H₂O

2) CH₃COCH₃ + CN^- → (CH₃)₂C(CN)(OH)

3) C₆H₆ + CH₃CO⁺ → C₆H₅COCH₃

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