Class-12-Chemistry-board-exam-questions

 CLASS XII CBSE BOARD EXAM CHEMISTRY IMPORTANT QUESTIONS

                                                       

CBSE Class 12 Chemistry – Chapter-wise Marks Distribution

S. No.	Title	Marks
1	Solutions	7
2	Electrochemistry	9
3	Chemical Kinetics	7
4	d- and f-Block Elements	7
5	Coordination Compounds	7
6	Haloalkanes and Haloarenes	6
7	Alcohols, Phenols and Ethers	6
8	Aldehydes, Ketones and Carboxylic Acids	8
9	Amines	6
10	Biomolecules	7
TOTAL		70

                                                                UNIT 1 SOLUTION 

Question 1: When silicon is doped with arsenic, what kind of semiconductor is produced?

Question 2: When silicon is doped with arsenic, what kind of semiconductor is produced?

Isotonic solutions: what are they?

Question 3: Certain liquids create "azeotropes" when they mix. "Azeotropes": what are they?

Question 4: What kind of attractive intermolecular interaction is present between methanol and acetone?
Question 5: Which of BaCl₂ and KCl is better at causing a negatively charged colloidal sol to coagulate? Give an explanation.

Question 6: Raoult's law deviates from non-ideal solutions either positively or negatively. What causes these deviations, and what are they? Describe each class with one example.

Question 7: Give definitions for the terms "osmosis" and "osmotic pressure."
What is the benefit of determining the molar masses of solutes in solutions using osmotic pressure as opposed to other colliding properties?

Question  8: Give definitions for the following terms:

(i) Mole fraction; (ii) Isotonic solutions; (iii) Van't Hoff factor; (iv) Optimal solution

Question 9: Describe why cold water is more comfortable for aquatic animals than warm water.

Question 10: Describe Henry's law and list two significant uses for it.

Question 11: Why do gases almost always become less soluble in liquids as the temperature rises?

Question 12: Below 273 K, a sodium chloride aqueous solution freezes. Using an appropriate illustration, describe how the freezing points of water are dropping.

Question 13: Why do gases almost always become less soluble in liquids as the temperature rises? (All India Committee, 2012).

Question 14: In a saucepan, 1 kg of water is used to dissolve 18 g of glucose, C₆H₁₂O₆ (molar mass: 180 g mol⁻¹). What is the boiling point of this solution? (The boiling point of pure water is 373.15 K; Kb for water is 0.52 K kg mol⁻¹.)

Question 15 (i) The volume of the resultant solution drops when liquid X and liquid Y are mixed. What kind of departure from Raoult's law does the final solution demonstrate? After combining liquids X and Y, what temperature shift would you notice?
(ii) What happens if the blood cell is submerged in a hypotonic solution of water? Give an explanation. (All India, 2015)

Question 16: Give definitions for the following terms: (2017, Delhi)

(i) Colligative characteristics (ii) Molality (m)

Question 17: Describe why the boiling point of water rises when one mol of glucose is added to one liter of water. (Delhi Committee, 2017)

Question 17: A solution of 10.0 mL is created by dissolving 100 mg of a protein in just enough water. What is the protein's molar mass if the osmotic pressure in this solution is 13.3 mm Hg at 25°C?

(R = 0.0821 L atm mol⁻¹ K⁻¹ and 760 mm Hg = 1 atm.) (All India & Delhi, 2009)

Question 18: The boiling point of a solution made by dissolving 1.25 g of wintergreen oil (methyl salicylate) in 99.0 g of benzene is 80.31°C. Find this compound's molar mass. (Kb for benzene = 2.53°C kg mol⁻¹ and B.P. of pure benzene = 80.10°C) Delhi (2010)

Question 19: To reduce the freezing point by 7.5°C, how much NaCl (molar mass = 58.5 g mol-1) must dissolve in 65 g of water? Water has a freezing point depression constant (Kf) of 1.86 K kg mol-1. Assume that the van't Hoff factor for NaCl is 1.87. (All India, 2010)

Question 20: At 298 K, the vapor pressure of a solution with precisely 30 g of non-volatile solute in 90 g of water is 2.8 kPa. This solution is supplemented with an additional 18 g of water. At 298 K, the new vapor pressure is 2.9 kPa. Determine (i) (i) (i) (i) (i) (i) (i) the solute's molecular mass and (ii) the water's vapor pressure at 298 K. (Delhi Committee, 2012)

Question 21: There is a 1.62 K drop in the freezing point of 3.9 g of benzoic acid dissolved in 49 g of benzene. Determine the solute's type (associated or dissociated) by calculating the Van't Hoff factor.

(Given: Kf for benzene = 4.9 K kg mol⁻¹, Molar mass of benzoic acid = 122 g mol-1) (2015, Delhi)

                        UNIT II Electrochemistry

First question: How does a catalyst affect a reaction's (i) Gibbs energy (ΔG) and (ii) activation energy?
Question 2: How does adding a catalyst affect

(a) Energy of activation (Ea), and

(b) A reaction's Gibbs energy (AG)?
Question 3.

Below are two electrochemical cell half-cell reactions:
MnO₄(aq) + 8H⁺(aq) + 5e⁻ → Mn²⁺(aq) + 4H₂O(l), E° = + 1.51 V Sn²⁺ (aq) → 4 Sn⁴⁺ (aq) + 2e⁻, E° = + 0.15 V
Create the redox equation using the two half-cell reactions, then determine whether the reaction favors the creation of the reactants or products indicated in the equation. 

Question 4: Describe the relationship between the conductivity of the solution, the resistance of the solution in the cell, and the cell constant. What is the relationship between a solution's conductivity and its molar conductivity?

Question 5:  Given that the standard electrode potentials (E°) of metals are :

K+/K = -2.93 V, Ag+/Ag = 0.80 V, Cu2+/Cu = 0.34 V,
Mg2+/Mg = -2.37 V, Cr3+/Cr = -0.74 V, Fe2+/Fe = -0.44 V.
Arrange these metals in increasing order of their reducing power.

Question 6: Two half-reactions of an electrochemical cell are given below :

MnO–4 (aq) + 8H+ (aq) + 5e– → Mn2+ (aq) + 4H2O (I), E° = 1.51 V
Sn2+ (aq) → Sn4+ (aq) + 2e–, E° = + 0.15 V.
Construct the redox reaction equation from the two half-reactions and calculate the cell potential from the standard potentials and predict if the reaction is reactant or product favoured.

Question 7: Two half-reactions of an electrochemical cell are given below :

MnO–4 (aq) + 8H+ (aq) + 5e– → Mn2+ (aq) + 4H2O (I), E° = 1.51 V

Sn2+ (aq) → Sn4+ (aq) + 2e–, E° = + 0.15 V.

Construct the redox reaction equation from the two half-reactions and calculate the cell potential from the standard potentials and predict if the reaction is reactant or product favoured.

Question 8: Determine the values of equilibrium constant (Kc) and ΔG° for the following reaction:

Ni(s) + 2Ag+ (aq) → Ni2+ (aq) + 2Ag(s),

E° = 1.05 V

(1F = 96500 C mol-1)

Question 9: Two half-reactions of an electrochemical cell are given below :

MnO₄⁻ (aq) + 8H⁺ (aq) + 5e– → Mn²⁺ (aq) + 4H₂O (I), E° = 1.51 V

Sn²⁺ (aq) → Sn⁴⁺ (aq) + 2e⁻, E° = + 0.15 V.

Construct the redox equation from the standard potential of the cell and predict if the reaction is reactant favored or product favored.

Question 10: A zinc rod is dipped in 0.1 M solution of ZnSO₄. The salt is 95% dissociated at this dilution at 298 K. Calculate the electrode potential.

[E°Zn²⁺/Zn = – 0.76 V]

Question 11: The conductivity of 0.20 M solution of KCl at 298 K is 0.025 S cm-1. Calculate its molar conductivity. (Delhi 2013)

Question12: State Kohlrausch law of independent migration of ions. Why does the conductivity of a solution decrease with dilution?

Question 13: Define the following terms :

(i) Rate constant (k)

(ii) Activation energy (Ea)

Question 14: (a) following reactions occur at the cathode during the electrolysis of aqueous silver chloride solution :

Ag⁺(aq) + e– → Ag(s) E° = +0.80 V

H+(aq) + e– → 12H2(g) E° = 0.00 V

On the basis of their standard reduction electrode potential (E°) values, which reaction is feasible at the cathode, and why?

(b) Define limiting molar conductivity. Why conductivity of an electrolyte solution decrease with the decrease in concentration?

Question 15: From the given cells: Lead storage cell, Mercury cell, Fuel cell and Dry cell

Answer the following:

(i) Which cell is used in hearing aids?

(ii) Which cell was used in the Apollo Space Program?

(iii) Which cell is used in automobiles and inverters?

(iv) Which cell does not have long life?(Delhi 2016)

Question 16: Calculate the degree of dissociation (a) of acetic acid if its molar conductivity (Λm) is 39.05 S cm2 mol-1.

Given: λ°(H+) = 349.6 S cm² mol⁻¹ and λ°(CH3COO–) = 40.9 S cm2 mol-1 (Delhi 2017)

Question 15: The Following reactions can occur at cathode during the electrolysis of aqueous silver nitrate solution using Pt electrodes :

On the basis of their standard electrode potential values, which reaction is feasible at the cathode, and why?

Question 17:  A copper-silver cell is set up. The copper ion concentration in it is 0.10 M. The concentration of silver ion is not known. The cell potential is measured at 0.422 V. Determine the concentration of silver ion in the cell.

Given : E°Ag+/Ag = + 0.80 V, E° Cu2+/Cu = + 0.34 V. (All India 2009)

 

Question 18: When a certain conductance cell was filled with 0.1 M KCl, it has a resistance of 85 ohms at 25°C. When the same cell was filled with an aqueous solution of 0.052 M unknown electrolyte, the resistance was 96 ohms. Calculate the molar conductance of the electrolyte at this concentration.

[Specific conductance of 0.1 M KCl = 1.29 × 10⁻² ohm⁻¹ cm⁻¹]

Question 19: The cell in which the following reaction occurs :

2Fe3+ (aq) + 2I⁻ (aq) → 2Fe2+ (aq) + I2 (s) has E₀ cell = 0.236V at 298K. Calculate the standard Gibbs energy and the equilibrium constant of the cell reaction.

(Antilog of 6.5 = 3.162 × 106; of 8.0 = 10 × 108; of 8.5 = 3.162 × 108)

UNIT III CHEMICAL KINETICS

Question1: Define ‘order of a reaction’

Question 2: Define ‘activation energy’ of a reaction

Question 3: Express the rate of the following reaction in terms of the formation of ammonia :

N2(g) + 3H2(g) → 2NH3(g)

Question 4: Write the unit of rate constant for a zero order reaction.

Question 5: A reaction is of second order with respect to a reactant. How will the rate of reaction be affected if the concentration of this reactant is

(i)               doubled, (ii) reduced to half?

Question 6: Distinguish between ‘rate expression’ and ‘rate constant’ of a reaction

Question 7: What do you understand by the rate law and rate constant of a reaction? Identify the order of a reaction if the units of its rate constant are : (i) L-1 mol s-1 (ii) L mol-1 s-1

Question 8: The thermal decomposition of HCO2H is a first order reaction with a rate constant of 2.4 × 10-3 s-1 at a certain temperature. Calculate how long will it take for three-fourths of initial quantity of HCO2 H to decompose. (log 0.25 = -0.6021)

 

Question 9: A reaction is of second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is reduced to half? What is the unit of rate constant for such a reaction? (All India 2011)

Question 10: A reaction is of second order with respect to a reactant. How is its rate affected if the concentration of the reactant is (i) doubled (ii) reduced to half?

Question 10: A first order gas phase reaction : A2B2(g) → 2A(g) + 2B(g) at the temperature 400°C has the rate constant k = 2.0 × 10-4 sec-1. What percentage of A2B2 is decomposed on heating for 900 seconds? (Antilog 0.0781 = 1.197)

Question 11: Define the following terms :

(a) Pseudo first order reaction.

(b) Half life period of reaction (t1/2).

Question 12: a) For a reaction, A + B → Product, the rate law is given by, Rate = k[A]1[B]2. What is the order of the reaction?

(b) Write the unit of rate constant ‘k’ for the first order reaction

Question 13: How does a change in temperature affect the rate, of a reaction? How can this effect on the rate constant of a reaction be represented quantitatively? (Comptt. All India 2014)

Question 14: Define each of the following :

(i) Specific rate of a reaction

(ii) Energy of activation of a reaction

Question 15: Derive integrated rate equation for rate constant of a first order reaction

Question 16: For a decomposition reaction the values of rate constant k at two different temperatures are given below :

k1 = 2.15 × 10-8 L mol-1 s-1 at 650 K

k2 = 2.39 × 10-7 L mol-1 s-1 at 700 K

Calculate the value of activation energy for this reaction.

(R = 8.314 J K-1 mol-1) (All India 2009)

Question 17: The rate of a reaction becomes four times when the temperature changes from 293 K to 313 K. Calculate the energy of activation (Ea) of the reaction assuming that it does not change with temperature. [R = 8.314 JK-1 mol-1, log 4 = 0.6021] (All India 2013)

Question 18: The rate constant for the first order decomposition of H2O2 is given by the following equation:

log k = 14.2 – 1.0×104TK

Calculate Ea for this reaction and rate constant k if its half-life period be 200 minutes.

(Given: R = 8.314 J K-1 mol-1) (Delhi 2016)

Question 19: Following data are obtained for the reaction:
N₂O₅ → 2NO₂ + 12O₂

t/s	0	300	600
[N205]/mol L-1	1.6 × 10-2	0.8 × 10-2	0.4 × 10-2

(a) Show that it follows first order reaction.
(b) Calculate the half-life.
(Given log 2 = 0.3010 log 4 = 0.6021) (Delhi 2016)

Question 20: (a) With the help of a labelled diagram explain the role of activated complex in a reaction.

(b) A first order reaction is 15% completed in 20 minutes. How long will it take to complete 60% of the reaction ? (Comptt. Delhi 2012)

UNIT IV d- and f-Block Elements

1.      What is meant by ‘lanthanoid contraction’?

2.      Why do transition elements show variable oxidation states?

3.      Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group number

4.      Write the formula of an oxo-anion of Chromium (Cr) in which it shows the oxidation state equal to its group number. (Delhi 2017)

5.      Explain the following observations :
(i) Generally there is an increase in density of elements from titanium (Z = 22) to copper (Z = 29) in the first series of transition elements.
(ii) Transition elements and their compounds are generally found to be good catalysts in chemical reactions. (Delhi 2010)

6.      Assign reasons for the following :
(i) Copper (I) ion is not known in aqueous solution.
(ii) Actinoids exhibit greater range of oxidation states than lanthanoids

7.      How would you account for the following :
(i) Cr²⁺ is reducing in nature while with the same d-orbital configuration (d⁴) Mn³⁺ is an oxidising agent.
(ii) In a transition series of metals, the metal
which exhibits the greatest number of oxidation states occurs in the middle of the series.

8.      State reasons for the following :
(i) Cu (I) ion is not stable in an aqueous solution.
(ii) Unlike Cr³⁺, Mn²⁺, Fe³⁺ and the subsequent other M²⁺ ions of the 3d series of elements, the 4d and the 5d series metals generally do not form stable cationic species. (All India 2011)

9.      Explain giving a suitable reason for each of the following :
(i) Transition metals and their compounds are generally found to be good catalysts.
(ii) Metal-metal bonding is more frequent for the 4d and the 5d series of transition metals than that for the 3d series. (All India 2011)

10.  Complete the following chemical equations : (Delhi 2012)

11.  Explain the following :
(a) The enthalpies of atomization of transition metals are quite high.
(b) The transition metals and many of their compounds act as good catalysts. (Comptt. Delhi 2012)

12.  What is meant by ‘disproportionation’? Give an example of a disproportionation reaction in aqueous solution. (Comptt. Delhi 2015)

13.  Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with oxalic acid? Write the ionic equations for the reactions. (Comptt. All India 2015)

14.  Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with
(i) iodine (ii) H₂S. (Comptt. All India 2015)

15.  When chromite ore FeCr₂O₄ is fused with NaOH in presence of air, a yellow coloured compound (A) is obtained which on acidification with dilute sulphuric acid gives a compound (B). Compound (B) on reaction with KC1 forms an orange coloured crystalline compound (C).
(i) Write the formulae of the compounds (A), (B) and (C).
(ii) Write one use of compound (C). (Delhi 2016)

16.  How would you account for the following :
(i) Many of the transition elements and their compounds can act as good catalysts.
(ii) The metallic radii of the third (5d) series of transition elements are virtually the same as those of the corresponding members of the second series.
(iii) There is a greater range of oxidation states among the actinoids than among the lanthanoids. (All India 2009)

17.  Explain the following observations giving an appropriate reason for each.
(i) The enthalpies of atomization of transition elements are quite high.
(ii) There occurs much more frequent metal- metal bonding in compounds of heavy transition metals (i.e. 3^rd series).
(iii) Mn²⁺ is much more resistant than Fe²⁺ towards oxidation. (Delhi 2012)

18.  Explain the following observations :
(i) Many of the transition elements are known to form interstitial compounds
(ii) There is a general increase in density from titanium (Z = 22) to copper (Z = 29).
(iii) The members of the actinoid series exhibit a larger number of oxidation states than the corresponding members of the lanthanoid series. (All India 2012)

19.  Explain each of the following observations :
(i) With the same d-orbital configuration (d⁴), Cr²⁺ is a reducing agent while Mn³⁺ is an oxidising agent.
(ii) Actinoids exhibit a much larger number of oxidation states than the lanthanoids.
(iii) There is hardly any increase in atomic size with increasing atomic numbers in a series of transition metals. (All India 2012)

20.  A mixed oxide of iron and chromium is fused with sodium carbonate in free access of air to form a yellow coloured compound (A). On acidification the compound (A) forms an orange coloured compound (B), which is a strong oxidizing agent. Identify compound (A) and (B). Write chemical reactions involved. (Comptt. All India 2017)

21.  (a) Give reasons for the following:
(i) Compounds of transition elements are generally coloured.
(ii) MnO is basic while Mn₂O₇ is acidic.
(iii) Calculate the magnetic moment of a divalent ion in aqueous medium if its atomic number is 26. (Comptt. All India 2017)

22.  (a) Why do transition elements show variable oxidation states?
(i) Name the element showing maximum number of oxidation states among the first series of transition metals from Se (Z = 21) to Zn (Z = 30).
(ii) Name the element which shows only +3 oxidation state.
(b) What is lanthanoid contraction? Name an important alloy which contains some of the lanthanoid metals. (All India 2013)

23.  Give reasons :
(i) Zirconium (Z = 40) and Hafnium (Z = 72) have almost similar atomic radii.
(ii) d-block elements exhibit more oxidation states than f-block elements.
(iii) The enthalpies of atomization of the transition metals are high.
(iv) The variation in oxidation states of transition metals is of different type from that of the non-transition metals.
(v) Orange solution of potassium dichromate

24.  The elements of 3d transition series are given as:
Se Ti V Cr Mn Fe Co Ni Cu Zn
Answer the following:
(i) Write the element which shows maximum number of oxidation states. Give reason.
(ii) Which element has the highest m.p.?
(iii) Which element shows only +3 oxidation state?
(iv) Which element is a strong oxidizing agent in +3 oxidation state and why? (All India)

UNIT V Coordination Compounds

1. Give an example of linkage isomerism. (Delhi) 2010

2. Give IUPAC name of ionization isomer of [Ni(NH3)3NO3]Cl. (Comptt. All India 2012)

3.         Write down the formula of : Tetraamineaquachloridocobalt(III) chloride. (Comptt. All India 2012)

4. Which complex ion is formed when undecomposed AgBr is washed with hypo solution in photography? (Comptt. All India 2013)

5. Give IUPAC name of the ionization isomer of [Ni(NH3)3NO3]Cl. (Comptt. All India 2013)

6. Give two examples of ligands which form coordination compounds useful in analytical chemistry. (Comptt. All India 2013)

7. Which of the following is more stable complex and why?

[Co(NH3)6]3+ and [Co(en)3]3+ (Delhi 2014)

8. What is meant by chelate effect? (Comptt. All India 2015)

9. Why are low spin tetrahedral complexes not formed? (Comptt. Delhi 2017)

10. Write IUPAC name of the complex: [CoCl2(en)2]+ (Comptt. All India 2017)

11. Name the following coordination compounds according to IUPAC system of nomenclature :

(i) [Co(NH3)4 (H2O)Cl]Cl2

(ii) [CrCl2(en)2]Cl,

(en = ethane – 1, 2 – diamine) (Delhi 2010)

12. Describe the shape and magnetic behaviour of following complexes :
(i) [CO(NH₃)₆]³⁺
(ii) [Ni(CN)₄]^2- (At. No. Co = 27, Ni = 28) (Delhi 2010)

13. How is the stability of a co-ordination compound in solution decided ?
How is the dissociation constant of a complex defined? (Comptt. All India 2012)

14. Explain why [Co(NH3)6]3+ is an inner orbital complex whereas [Ni(NH3)6]2+ is an outer orbital complex. (At. no. Co = 27, Ni = 28) (Comptt. All India 2013)

15. When a co-ordination compound CrCl3.6H2O is mixed with AgNO3, 2 moles of AgCl are precipitated per mole of the compound. Write

(i) Structural formula of the complex.

(ii) IUPAC name of the complex. (Delhi 2016)

16. Using IUPAC norms write the formulae for the following:

(i) Sodium dicyanidoaurate (I)

17. For the complex [Fe(en)₂Cl₂], Cl, (en = ethylene diamine), identify
(i) the oxidation number of iron,
(ii) the hybrid orbitals and the shape of the complex,
(iii) the magnetic behaviour of the complex,
(iv) the number of geometrical isomers,
(v) whether there is an optical isomer also, and
(vi) name of the complex. (At. no. of Fe = 26) (Delhi 2009)

18. Compare the following complexes with respect to their shape, magnetic behaviour and the hybrid orbitals involved :
(i) [CoF₄]^2-
(ii) [Cr(H₂O)₂(C₂O₄)₂]^–
(iii) [Ni(CO)₄] (Atomic number : Co = 27, Cr = 24, Ni = 28) (Delhi 2009)

19. Giving a suitable example for each, explain the following :
(i) Crystal field splitting
(ii) Linkage isomerism
(iii) Ambidentate ligand (All India 2009)

20. Explain the following :
(i) Low spin octahedral complexes of nickel are not known.
(ii) The π-complexes are known for transition elements only.
(iii) CO is a stronger ligand than NTL, for many metals. (All India 2009)

21. Explain the following cases giving appropriate reasons :
(i) Nickel does not form low spin octahedral complexes.
(ii) The n-complexes are known for the transition metals only. (All India 2010)

21. Explain the following terms giving a suitable example in each case :
(i) Ambident ligand
(ii) Denticity of a ligand
(iii) Crystal field splitting in an octahedral field

22. State a reason for each of the following situations :

(i) Co2+ is easily oxidized to Co3+ in presence of a strong ligand.

(ii) CO is a stronger complexing reagent than NH3.

(iii) The molecular shape of [Ni(CO)4] is not the

same as that of [Ni(CN)4]2- (Delhi 2011)

23. Write the name, the structure and the magnetic behaviour of each one of the following complexes :
(i) [Pt(NH₃)₂Cl(NO₂)]
(ii) [Co(NH₃)₄Cl₂]Cl
(iii) Ni(CO)₄ (Atmos. Co = 27, Ni = 28, Pt = 78) (Delhi 2011)

24. (a) Give two examples of coordination compounds used in industries.

(b) Using valence bond theory, explain the geometry and magnetic behaviour of [Co(NH3)6]3+

(At. no. of Co = 27) (Comptt. Delhi 2011)

25. What is meant by crystal field splitting energy? On the basis of crystal field theory, write the electronic configuration of d⁴ in terms of t_2g and e_g in an octahedral field when
(i) Δ₀ > P
(ii) Δ₀ < P (All India 2013)

26. (a) How is a double salt different from a complex?
(b) Write IUPAC names of the following :
(i) K₃[Fe(C₂O₄)₃]
(ii) [Pt(NH₃)₆]Cl₄.
(c) Draw the structure of cis isomer of [CO(NH₃)₄Cl₂]⁺ (Comptt. Delhi 2013)

27. (a) For the complex [Fe(H₂O)₆]³⁺, write the hybridization, magnetic character and spin of the complex. (At. number: Fe = 26)
(b) Draw one of the geometrical isomers of the complex [Pt(en)₂Cl₂]²⁺ which is optically inactive. (All India 2016)

28. (a) What type of isomerism is shown by the complex [Co(NH₃)₅ (SCN)]²⁺?
(b) Why is [NiCl₂₄]^2- paramagnetic while [Ni(CN)₄]^2- is diamagnetic? (Atomic number of Ni = 28)
(c) Why are low spin tetrahedral complexes rarely observed? (All India 2017)

 

 UNIT VI  Haloalkanes and Haloarenes

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           Unit 7-8 Download here
 

                                          UNIT 8 AMINES

1. Give the IUPAC name of H2N — CH2—CH2—CH = CH2. (Delhi 2010)

2. Arrange the following compounds in an increasing order of their solubility in water : C6H5NH2, (C2H5)2NH, C2HSNH2 (Delhi & All India 2011)

3. Give a chemical test to distinguish between ethylamine and aniline. (All India 2011)

4. Arrange the following in increasing order of their basic strength in aqueous solution: CH3.NH2, (CH3)3N, (CH3)2NH (Delhi 2013)

5. Arrange the following in increasing order of basic strength (Comptt. All India 2015)

Aniline, p-Nitroaniline and p-Toluidine

6. Write the IUPAC name of the given compound: (Delhi 2016)

7. Give the chemical tests to distinguish between the following pairs of compounds :
(i) Ethyl amine and Aniline
(ii) Aniline and Benzylamine (All India 2010)

8. Identify A and B in each of the following processes : (All India 20100

9. Give the chemical tests to distinguish between the following pairs of compounds :
(i) Methylamine and Dimethylamine
(ii) Aniline and N-methylaniline (All India 2010)

10. Describe the following giving the relevant chemical equation in each case :
(i) Carbylamine reaction
(ii) Hofmann’s bromamide reaction (All India 2012)

11. How are the following conversions carried out :
(a) Aniline to p-hydroxyazobenzene
(b) Ethanoyl chloride to Ethanenitrile. (Comptt. Delhi 2012)

12. How would you account for the following :
(a) Aniline is a weaker base than cyclohexyl amine.
(b) Methylamine in aqueous medium gives reddish-brown precipitate with FeCl3. (Comptt. All India 2012)

13. How would you account for the following :
(a) Electrophilic susbstitution in case of aromatic amines takes place more readily than benzene.
(b) Ethanamide is a weaker base than ethanamine. (Comptt. All India 2012)

14. Illustrate the following reactions :
(a) Sandmeyer’s reaction
(b) Coupling reaction (Comptt. All India 2012)

15. Give chemical tests to distinguish between the following pairs of compounds :
(a) Aniline and Ethylamine
(b) Ethylamine and Dimethylamine (Comptt. Delhi 2013)

16. Write the chemical equations involved in the following reactions: (All India 2016)
(i) Hoffmann-bromamide degradation reaction
(ii) Carbylamine reaction

17.Complete the following chemical equations : (Delhi)

17. Write chemical equations for the following conversions :

(i) Nitrobenzene to benzoic acid.
(ii) Benzyl chloride to 2-phenylethanamine
(iii) Aniline to benzyl alcohol. (Delhi 2012)

18. Give the structures of A, B and C in the following reactions : (Delhi 2014)

19. (a) Write the structures of main products when benzene diazonium chloride reacts with the following reagents :

(i) H3PO2 + H2O (ii) CuCN/KCN (iii) H2O
(b) Arrange the following in the increasing order of their basic character in an aqueous solution :
C2H5NH2, (C2H5)2NH, (C3H5)3N
(c) Give a simple chemical test to distinguish between the following pair of compounds :
C6H5—NH2 and C6H5—NH—CH3 (All India 2015)

                                                                   Unit 10   Biomolecules

1. What are the expected products of hydrolysis of lactose ? (Comptt. Delhi 2012)

2. What are three types of RNA molecules which perform different functions? (Delhi 2013)

3. Name one water soluble vitamin which is a powerful antioxidant. Give its one natural source.

(Comptt. Delhi 2013)

4. Mention one important function of nucleic acids in our body. (Comptt. All India 2013)

5. What are the products of hydrolysis of maltose? (All India 2014)

6. Write the products of hydrolysis of lactose. (All India 2014)

7. Explain what is meant by (Delhi 2009)

(i) a peptide linkage
(ii) a glycosidic linkage.

8. Name two water soluble vitamins, their sources and the diseases caused due to their deficiency in diet. (Delhi 2009)

9. Name the four bases present in DNA. Which one of these is not present in RNA? (All India 2009)

10. Explain the following terms :
(i) Invert sugar
(ii) Polypeptides (Delhi 2009)

11. What are essential and non-essential amino acids in human food? Give one example of each type.(Delhi 2009)

12. State clearly what are known as nucleosides and nucleotides. (Delhi 2009)

13. Describe what you understand by primary structure and secondary structure of proteins. (Delhi 2009)

14. Name the bases present in RNA. Which one of these is not present in DNA? (Delhi 2009)

15. Write the main structural difference between DNA and RNA. Of the four bases, name those which are common to both DNA and RNA. (All India 2009)

16. Write down the structures and names of the products formed when D-glucose is treated with
(i) Hydroxylamine
(ii) Acetic anhydride. (Comptt. All India 2012)

17. Enumerate the reactions of glucose which cannot be explained by its open chain structures. (Comptt. Delhi 2014)

18.Amino acids may be acidic, alkaline or neutral. How does this happen? What are essential and non-essential amino acids? Name one of each type. (All India 2010)

19. Define the following as related to proteins :
(i) Peptide linkage
(ii) Primary structure
(iii) Denaturation (All India 2012)