Class XII CHEMISTRY chapter 1, 2, 3 AND 4 PRACTICE PAPER

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CLASS –XII   SUBJECT: CHEMISTRY (UT-1, 2, 3 AND 4)   PRACTICE PAPER

TIME: 3 hr  

MAXIMUM MARKS: 70

NOTE: All questions are compulsory

MCQs Section A

Q1 The value of van’t Hoff factor for ethanoic acid in benzene is (a) 1.0 (b) 1.5 (c) 0.5 (d) 2

 Q2 Which of the following aqueous solutions should have the highest boiling point? (a) 1.0 M NaOH (b)      1.0 M Na2SO4 (c) 1.0 M NH4NO3 (d) 1.0 M KNO3

Q3 In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl2      solution is _____________.(a) the same (b) about twice (c) about three times (d) about six times

Q4 If we place the blood cells in a solution containing less than 0.9% (m/V) sodium chloride. They would     swell. This is because (a) the solution is hypotonic (b) the solution is isotonic (c) the solution is      hypertonic (d) none of these

Q5 The positive value of the standard electrode potential of Cu2+/Cu indicates that ______________.  (a) this redox couple is a stronger reducing agent than the H+ /H2 couple. (b) this redox couple is a stronger oxidising agent than H+ /H2. (c) Cu can displace H2 from acid. (d) Cu cannot displace H2 from acid

Q6 On increasing temperature, (a) ionic conductance increases and electronic conductance decreases. (b) ionic conductance decreases and electronic conductance increases. (c) both ionic and electronic       conductance increase. (d) both ionic and electronic conductance decrease

Q7 Charge carried by 1 mole of electrons is    (a) 6.023 × 1023 coulomb (b) 9.65 × 104 coulomb (c) 1.6 ×       10–19 coulomb  (d) 6.28 × 1019 coulomb

Q8 Which of the following is a zero order reaction? (a) Decomposition of N2O5 (b) Decomposition of     NH3 (c) Decomposition of N2O (d) Radioactive decay of unstable nuclei

Q9 The half life of a first order reaction is 69.35 sec.      The value of rate constant of the reaction is (a)       1.0 s–1 (b) 0.1 s–1 (c) 0.01 s–1 (d) 0.001 s–1

Q10 The magnetic moment is associated with its spin angular momentum and orbital         momentum.        Spin only magnetic moment value of Cr3+ ion is ____________. (a) 2.87 B.M. (b) 3.87 B.M. (c) 3.47         B.M. (d) 3.57 B.M.

Q11 Transition elements show magnetic moment due to spin and orbital motion of electrons. Which of        the following metallic ions have almost same spin only magnetic moment?  (a)       Co2+    (b) Cr2+          (c) Mn2+ (d) Cr3+

Q12 The electronic configuration of Cu(II) is 3d 9 whereas that of Cu(I) is 3d10. Which of the following is correct? (a) Cu(II) is more stable (b) Cu(II) is less stable (c) Cu(I) and Cu(II) are equally stable (d) Stability of Cu(I) and Cu(II) depends on nature of copper salt

Assertion-Reason Questions In the following questions, two statements are given—one labeled Assertion (A) and the other labeled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:

(a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).

(b) Both Assertion (A) and Reason (R) are correct statements, but Reason (R) is not the correct explanation of the Assertion (A).

(c) Assertion (A) is correct, but Reason (R) is incorrect statement.

 (d) Assertion (A) is incorrect, but Reason (R) is correct statement

Q13 Assertion (A) : Zn, Cd and Hg cannot be regarded as transition elements. .

       Reason (R) : These  elements do not belong to the d-block of the periodic table.

Q14 Assertion (A) : Rusting of iron is quicker in saline water than in ordinary water.

         Reason (R) : Salt water helps in flow of current in the miniature cell developed on the iron surface.

Q15 Assertion (A) : Order of the reaction can be zero or fractional.

        Reason (R) : We cannot determine  order from balanced chemical equation.

Q16 Assertion (A) : The solubility of a gas in a liquid increases with increase of pressure.

         Reason (R) : The solubility of a gas in a liquid is directly proportional to the pressure of the gas.

EACH QUESTION CARRY 2 MARKS  (12) SECTION B

Q17 Define Molecularity of a Reaction  and pseudo order reaction  with examples

Q18  Units of Zero order reaction and first order of reaction

Q19 A solution of Ni(NO3)2 is electrolysed between platinum electrodes using  a current of 5 amperes for 20 minutes. What mass of Ni is deposited at the cathode?

Q20  Discuss the  Variation of Conductivity and Molar Conductivity with Concentration

Q21.  State Henry’s law and mention some important applications?

Q22 Based on solute-solvent interactions, arrange the following in order of increasing solubility in n-octane and explain. Cyclohexane, KCl, CH3OH, CH3CN.

EACH QUESTION CARRY3 MARKS (18) SECTION C

Q23 What is meant by positive and negative deviations from Raoult's law and how is the sign of ΔmixH related to positive and negative deviations from Raoult's law.

Q24 The vapour pressure of pure liquids A and B are 450 and 700 mm Hg respectively, at 350  K . Find out the composition of the liquid mixture if total vapour pressure is 600 mm Hg. Also find the composition of the vapour phase.

Q25 Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate? Or

How does the acidified permanganate solution react with (i) iron(II) ions (ii) SO2and (iii) oxalic acid? Write the ionic equations for the reactions.

Q26 Give examples and suggest reasons for the following features of the transition metal chemistry:

(i)The lowest oxide of transition metal is basic, the highest is amphoteric/acidic.

(ii)A transition metal exhibits highest oxidation state in oxides and fluorides.

(iii) The highest oxidation state is exhibited in oxoanions of a metal.

Q27 (i) State two advantages of H2—O2 fuel cell over ordinary cell

(ii) What type of a battery is lead storage battery? Write the anode and cathode reactions and the overall cell reaction occurring in the operation of a lead storage battery

Q28 i) Calculate ∆r G° for the reaction        Mg(s) + Cu2+(aq)                 Mg2+(aq) + Cu(s) Given: Eo cell = +2.71 V, 1 F = 95600 C mol–1 (ii) Name the type of cell which was used in Apollo space programme for providing electrical power.

EACH QUESTION CARRY 4 MARKS (9)  SECTION D

Q29 The d-block elements are those elements in which the last electron enters the d-subshell of the penultimate shell. The general electronic configuration of these elements is (n – 1) d1–10 ns 1–2, where n is outermost shell. The d-block consisting of groups 3–12 occupies the large middle section of the periodic table. The elements of d-block are also known as transition elements as they possess properties that are transitional between the s and p block elements. A transition element is defined as an element which has incompletely filled d-orbitals in its ground state or any one of its oxidation states. There are four series of transition elements spread between group 3 and 12. First transition series or 3d-series: Scandium (21Sc) to Zinc (30Zn), Second transition series or 4d-series: Yttrium (39Y) to Cadmium (48Cd), Third transition series or 5d-series: Lanthanum (57La) and Hafnium (72Hf) to Mercury (80Hg) (Omitting 58Ce to 71Lu), Fourth transition series or 6d-series: Begins with Actinium (89Ac) is still incomplete.

In what way is the electronic configuration of transition elements different from that of the nontransition elements?

2. Why is zinc not regarded as a transition clement?

3. Why does a transition series contain 10 elements?

4. Name the element which shows outer electronic configuration 3d3 4s 2

5. What are interstitial compounds?

Q30 A solution which obeys Raoult’s law strictly is called an ideal solution, while a solution which shows deviations from Raoult’s law is called a non-ideal solution or real solution. Suppose the molecules of the solvent and solute are represented by A and B respectively, and let gAB, gAA and gBB are the attractive forces between A—B, A—A and B—B respectively. An ideal solution of the components A and B is defined as the solution in which the intermolecular interactions between the components A—B are of the same magnitude as the intermolecular interactions found in the pure components A—A and B—B. Similarly,a non- ideal solution of the components A and B is defined as the solution in which the intermolecular interactions between the components A—B are of the different magnitude as the intermolecular interactions found in the pure components A—A and B—B.

 1. What type of liquids form the ideal solution?

2. Give one example of an ideal solution.

 3. Write two characteristics of non-ideal solution

4. On mixing liquid A and liquid B, volume of the resulting solution decreases, what type of deviation from Raoult’s law is shown by?

EACH QUESTION CARRY 5 MARKS (15) SECTION E

Q31 (i) Define the following terms: (a) Azeotrope (b) Osmotic pressure (c) Colligative properties (ii) Calculate the molarity of 9.8% (w/w) solution of H2SO4 if the density of the solution is 1.02 g mL–1. (Molar mass of H2SO4 = 98 g mol–1)

Q32 i) State Kohlrausch law of independent migration of ions. Write an expression for the molar conductivity of acetic acid at infinite dilution according to Kohlrausch law. (ii) Calculate  for acetic acid. Given that   (HCl) = 426 S cm2 mol–1,  (NaCl) = 126 S cm2 mol–1   (CH3COONa) = 91 S cm2 mol–1

Q33 (i)The rate constant for a first order reaction is 60 s –1. How much time will it take to reduce the initial concentration of the reactant to its 1/16th value?

(ii) A reaction is first order in A and second order in B. (i) Write the differential rate equation. (ii) How is the rate affected on increasing the concentration of B three times? (iii) How is the rate affected when concentration of both A and B are doubled?

Important question of amines and diazonium salt

SUBJECT – CHEMISTRY THEORY (043) 2022-23

CHAPTER- AMINES

MM: 70                                                                            

TIME : 3 HOURS

General instructions: 

Read the following instructions carefully.

a) There are 35 questions in this question paper with internal choice.

b) Section A consist of 18 multiple-choice questions carrying 1 mark each.

c) Section B consists of 7 very short answer questions carrying 2 marks each.

d) Section C consists of 5 short answer questions carrying 3 marks each.

e) Section D consists of 2 case based questions carrying 4 marks each.

f) Section E consist of 3 long answer questions carrying 5 marks each.

g) All questions are compulsory.

h) Use of log tables and calculators is not allowed.

Section- A

The following questions are multiple choice questions with one correct answer each question carries one mark there is no internal choice in this section.

 

1. When a haloalkane is heated with KCN in aqueous ethanoic solution, the product formed is-

a) Alkyl nitrite                                                 

b) nitro alkane 

     c)  alkane nitrile                                                    

      d) carbylamine      

2. Amine that cannot be prepared by Gabriel phthalimide synthesis is-

a) Aniline                                                           

b)  benzyl amine 

     c) tertiary-butylamine 

     d) isobutylamine

3. Which of the following amine has highest boiling point?

a) Pentaamine  

b) 2-methylbutanamine

c) 2,2-dimethylpropamine

d) 3-methylbutamine              

4. The amine that reacts with NaNO2 and HCl to give yellow oily liquid is-

a) Ethylamine.    

b) Diethylamine

c) Isopropyl amine

d) Secondary butylamine    

5. Sandmeyer reaction of diazonium salt is a replacement of N2by-

a) Halogen Cl or Br

b) Hydroxyl group

c) Coupling

d) Hydrogen        

6. One of the following amines will not undergo Hoffmannbromamide reaction-

a) CH3CONHCH3

b) CH3CH2CONH2

c) CH3CONH2

d) C6H5CONH2   

7. The correct order of the basic strength of methyl substituted amines in aqueous solution is

a) CH3NH2 > (CH3)2NH > (CH3)3N

b) (CH3)2NH > CH3NH2 >  (CH3)3N

c) (CH3)3N >CH3NH2 > (CH3)2NH

d) (CH3)3N > (CH3)2NH > CH3NH2

8. The correct statement regarding the basicity of arylamine is

a) arylamines are generally more basic than alkylamines because of aryl group

b) arylamines are generally more basic than alkylamines because the nitrogen atom in aryalamines is sp- hybridised

c) arylamines are generally less basic than alkylamines because the nitrogen lone- pair electrons are delocalised by intraction with the aromatic ring π- electron system

d) arylamines are generally more basic than alkylamines because the nitrogen loan-pair electrons are not delocalisedby interaction with the aromatic ring π-electron system.            

9. What reagent is used in Hinsberg test of amines?

a) (CH3CO)2O and pyridine

b) C6H5SO2Cl followed by aq. NaOH

c) NaNO2 in aq. H2SO4

d) CH3I(excess) followed by AgOH  

10. Aniline reacts with sodium nitrite and hydrochloric acid at 273 -278 K to give:

a) Benzene

b) Benzene diazonium chloride

c) Chlorobenzene

d) o-chloroaniline    

11. Propane amide on reaction with bromine in aqueous NaOH gives:

a) Propanamine

b) ethanamine

c) N-Methyl ethanamine

d) Propanenitrile               

12. The gas evolved when methylamine reacts with nitrous acid is:

a) NH3

b) N2

c) H2

d) C2H6     

13. Which of the following is not correct regarding aniline?

a) It is less basic than ethyl amine

b) It can be steam distillated

c) It reacts with sodium to give hydrogen

d) It is soluble in water        

 

14. Acetamide and ethylamine can be distinguished by reacting with:

a) Aq. HCl and heat

b) Aq. NaOH and heat

c) Acidified KMnO4

d) Bromine water          

15. Given below are two statements labelled assertion (A) and reason(R).

Assertion(A)- Hinsberg's reagent can be used to distinguish primary amines from secondary amines.

Reason(R)- Benzenesulphonyl chloride is called Hinsberg'sreagent.

Select the most appropriate answer from the option given below :

a. Both A and R are true and R is the correct explanation of A.

b. Both A and R are true but R is not the correct explanation of A.

c. A is true but R is false.

d. A is false but R is true.             

16. Given below are two statements labelled assertion (A) and reason(R).

Assertion(A)- Solubility of amines in water decreases with increase in molar mass.

Reason(R)- Intermolecular H bonds formed by the higher amines are weaker.

Select the most appropriate answer from the option given below :

a. Both A and R are true and R is the correct explanation of A

b. Both A and R are true but R is not the correct explanation of A.

c. A is true but R is false.

d. A is false but R is true.             

17. Given below are two statements labelled assertion (A) and reason(R).

Assertion(A)- Amines behave as a Lewis base.

Reason(R)- Amines have an unshared pair of electrons on nitrogen atom.

Select the most appropriate answer from the option given below :

a. Both A and R are true and R is the correct explanation of A.

b. Both A and R are true but R is not the correct explanation of A.

c. A is true but R is false.

d. A is false but R is true.          

18. Given below are two statements labelled assertion (A) and reason(R).

Assertion(A)- Acylation of amines gives a mono substituted product whereas alkylation of amines gives poly substituted product.

Reason(R)- Acyl group sterically hinders the approach of further acyl groups.

Select the most appropriate answer from the option given below :

a. Both A and R are true and R is the correct explanation of A.

b. Both A and R are true but R is not the correct explanation of A.

c. A is true but R is false.

d. A is false but R is true.         

 

 

 

 

Section - B

This section contains 7 questions with internal choice in two questions. The following questions are very short answer type and carry 2 marks each.

 

19. How will you distinguish between the following pairs of compounds:

        i) Aniline and ethanamine.

       ii) Aniline and N-methylaniline

20. Give reasons:

        i) Aniline does not undergo friedal Craft reaction.

       ii) (CH3)2NH is more basic than (CH3)3N in an aqueous solution.

OR

       i) Although -NH2 group is o/p directing in electrophilic substitution reactions, yet aniline, on nitration gives good yield of m-nitroaniline.

      ii) pKb of methylamine is less than that of aniline.

21. Write chemical equations for the following conversion:

       i) nitrobenzene to benzenoic acid

       ii) aniline to benzyl alcohol

OR

        i) Write the reaction involved in the following: Diazotisation

       ii) Give reason:

            Aromatic diazonium salts are more stable than aliphatic diazonium salts.

22. Illustrate the following with an example of reaction in each case-

       i) Sandmeyer reaction

       ii) coupling reaction

23. Complete the following reactions:

       i) CH3CH2NH2 + CHCl3+alc.KOH------->

       ii) CH3NH2+ C6H5COCl---------->

24. Ammonolysis of alkyl halides is not a good method to prepare pure primary amines. Explain.

25. State and illustrate the following:

                    Gabriel phthalimide synthesis.

     

Section- C

Section contains 5 questions with internal choice in two questions the following questions are sort answer type and carry 3 marks each.

26.  a) Write the chemical reaction of methylamine with benzyl chloride and write the 

             IUPAC name of the product obtained.

       b) Arrange the following in the increasing order of their pkbvalues:

              C6H5NH2 , NH3 , C2H5NH2 ,(C2H5)2 NH

27. Write the structures of main products when aniline reacts with the following reagents:

          i) Br2 water.          

         ii) HCl

         iii) (CH3CO)2O/Pyridine

 

28. Write the structures of A, B and C in the following:

                                Br2/aq. KOH                      NaNO2+ConcHCl/0-5 0C                  KI/∆

      i) C6H5CONH2  ---------- ---------àA ------ ---------------à  B ------ ----à  C

                         KCN                         LiAlH4                             CHCl3+alcKOH

     II) CH3Cl ---- ----------à A ---- -----------à  B -------------------- ---à   C

 

29. Give reasons for any three of the following observations:

a. Aniline is acetylated before nitration reaction.

b. pKb of aniline is smaller than the m-nitro aniline.

c. Primary amine on treatment with benzene sulfonyl chloride forms a product which is soluble in NaOH, however secondary amine gives product which is insoluble in NaOH.

d. Aniline does not react with methyl chloride in the presence of anhydrous AlCl3 catalyst.

30. Write the structures of main products when benzenediazonium chloride reacts with 

      the following reagents.

a) CuCN

b) CH3CH2OH

c) KI

Section- D

The following questions are case based questions. Each question has an internal choice and carries 4(1+1+2) marks each. Read the passage carefully and answer the questions that follow.

 

31. Benzene ring in aniline is highly activated. This is due to the sharing of lone pair of nitrogen with the ring which results in increase in the electron density on the ring and hence facilitates the electrophilic attack. The substitution mainly takes place at Ortho and para positions because electron density is more at Ortho and para positions. On reaction with aqueous bromine all the ortho and para position get substituted resulting  in the formation of 2,4,6- tribromoaniline. To get a monobromocompound, the amino group is acetylated before bromination. After bromination, the bromoacetanilide is acid hydrolysed to give the desired halogenated amine.     

a) Why does -NH2 group facilitates electrophilic attack in aniline?

b) Explain why: in aniline, the substitution mainly takes place at Ortho and Para positions.

c) Show the conversion of benzene into aniline.

 

32. In amines the N atoms of the amino group are SP3hybridised. Amines readily lose its electron pair and act as a base. In aliphatic amines ,the alkyl group tends to increase the electron density on the nitrogen atom due to the +I effect. In aromatic amines, the basic strengths are influenced by the presence of an electron withdrawing group at the O-, m- and p- position in the ring.

a) Lower member of aliphatic amines are soluble in water .Why?

b) Out of (CH3)3N  and and (CH3)2NH which one is more basic in aqueous solution?

c) Which isomer of C3H9N which does not react with Hinsberg’s reagent.

 

 

Section- E

The following questions are long answer type and carry five marks each two questions have internal choice.

 

33. An organic compound A with molecular formula C7 H7NO reacts with Br2/aq. KOH to give compound 'B', which upon reaction with NaNO2 and HCl at 00 Celsius gives 'C'. Compound 'C' 

on heating with CH3CH2OH gives hydrocarbon 'D'.  compound 'B' on further reaction with Br2 water gives white precipitate of compound 'E'. Identify the compound A,B,C,D and 'E'.

Also justify your answer by giving relevant chemical equations.               

OR

An aromatic compound 'A' on treatment with aqueous ammonia and heating forms compound 'B' which on heating with Br2 and KOH forms a compound 'C' of molecular formula C6H7N. write the structure and IUPAC names of the compound A, B and C .Justify your answer by giving relevant chemical equations.          

34. i) Write the structure of main products when benzenediazonium chloride (C6H5N2+Cl-) reacts with the following reagents:

a) KI         b) C2H5OH

      ii) write the structures of A B and C in the following reactions:

                                                                     LiAlH4                                    HNO2 /Low temp

CH3Cl+ KCN (alc)----------------->A-- --------------------->B------------------------>C

                                                                           OR

     i) Write the reactions involved in the following:

a) Hoffmann’s Bromamide degradation reaction

b) Carbylamine reaction

35. i)    Convert the following:

a) Phenol to N-phenylethanamide

b) Chloroethane to methanamine

c) Propanenitrile to ethanal.

ii) What happens when-

a) N-ethylethaneamine reacts with benzenesulphonyl chloride.

b) Aniline reacts with chloroform in the presence of alcoholic potassium hydroxide.

 

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