Practice paper-1
Class-XII
Chemistry
[Section - A]
1. Which of the following is independent of temperature?
(a) Molarity
(b) Formality
(c) Normality
(d) Molality
2. The units of molar conductivity are;
(a) Ohm⁻¹m² mol⁻¹
(c) Ohm⁻¹ m² mol
(b) Ohm m²mol⁻¹
(d) Chm⁻² m²mol⁻¹
3. Rate Constant for a reaction is
Rate= K[A]²[B]⁻³/²
the order of reaction is:
(a) 3.0
(b) 0.5
(c) 1
(d) -0.5
4. Which element does not show Variable oxidation state?
(a) Sc
(b) V
(c) Fe
(d) Hg
5. What is the Coordination number of metal in [Co(en)2Cl2]Cl
(a) 4
(b) 5
(c) 6
(d) 3
6. CH3CH2OH--443k/conc.H2SO4---› X;what is X?
(a) CH2 = CH2
(b) C2H5OC2H5
(c) CH3OCH2CH3
(d) CH3CH2HHSO4
7. Reaction of ethylamine with chloroform in alcoholic KOH gives:
(a) C2H5CN
(b) C2H5NC
(c) CH3CN
(d) CH3NC
8. Vitamin B1 is Known as;
(a) Ascorbic acid
(b) Thiamine
(c) Riboflavin
(d) Pyridoxine
9. Which of the following does not undergo aldol condensation?
(a) ClCH2CHO
(b) CCl3CHO
(C) C6H5CH2CHO
(d) CH3CHO
10. Osmotic pressure is the minimum pressure that has to be applied on the solution to prevent the entry of solvent from ... to ...
11. Propanone on treatment with methyl magnesium iodide followed by hydrolysis from......
12. Vitamin B_{12} is a coordination compound of.......transition metal.
1 13. Among the ionic species Sc³⁺Ce³⁺ and Eu²⁺ which one is a good oxidising agent?
14. Draw structure of cyclopropanone Oxime.
15. Which of the following is most reactive towards SN² reaction?
CH3CH2Br ,(CH3)2CHBr,(CH3)3CHBr
Assertion - Reason Based questions:
The question below consists of two statements: Assertion (A) and Reason (R), answer the questions by selecting the appropriate 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. Assertion (A): o-nitrophenol is less soluble in water than the m-and p-isomers.
Reason (R): m-and p- nitrophenol exists as associated molecules.
17. Assertion (A): Acetophenone and Benzophenone can be distinguished by lodoform test.
Reason (R): Acetophenone and Benzophenone both are carbonyl compounds 1
18. Assertion (A): Both glucose and mannose from same osazone
Reason (R): Glucose and Mannose are aldohexoses.
[Section -B:]
19. The boiling point of benzene is 353.23 K. When 1.80 g of non-volatile solute was dissolved in 90g of benzene, the boiling point is raised to 354.11 K. Calculate the molar mass of the solute.Kb for benzene is 2.53 K Kg mol-¹.
20. For the first order reaction show that the time required for 99%completion of first order reaction is twice the time required for the completion of 90%
21. The resistance of 0.01N solution at 25°C is found to be 200 ohm.Calculate the equivalent conductivity of the solution if cell constant of the conductivity cell is unity.
22. Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why?
OR
What are interstitial compounds? Why are such compounds will know for transition metals?
23. Although chlorine is an electron withdrawing group, yet it is ortho-para directing in electrophilic aromatic substitution reactions, why?
OR
Aldehydes are more reactive than ketone towards Nucleophilic addition reactions. Explain.
24. What is the effect of denaturation on the structure of proteins?
25. State one reaction as an example in each case:
(i) Stephen's reduction
(ii) Etard reaction
OR
Describe the following:
(i) Cross Aldol condensation
(ii) H.V.Z reaction
[Section - C:]
26. Write three steps mechanism of acid dehydration of ethanol to yield Ethene.
OR
Write the Equation for the reaction of phenol with the following:
(i) Br₂/water
(ii) CHCl3 + NaOH
(iii) Na2Cr2O7 + conc.H2SO4
27. A solution (N*O_{3}) 2 electrolysed between platinum electrode using a current of 5 Ampere for 20 minutes.what mass of Ni is deposited at the cathode? (Ni = 58.7)
OR
Explain the Variation of molar conductivity of a strong Electrolyte and weak electrolyte with concentration through graph.
28. An organic compounds with molecular formula C9H10O forms 2,4 DNP derivatives, reduces Tollen's reagent and undergoes Cannizaro reaction. on vigorous oxidation, it gives 1,2-benzene dicarboxylic acid. Identify the compound.
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 structures and IUPAC names of Compounds A, B, C .
29. Give Simple Chemical test to distinguish between the following pairs of compounds:
(i) Propanal and Propanone
(ii) Aniline and Benzylamine
(iii) Benzoic acid and ethyl benzoate
30. (i) Indicate the steps in the preparation of K₂Cr₂O7 from the Chromite ore.
(ii) Why transition element have the high enthalpy of atomization?
[Section-D:]
31. Monosaccharides are simple carbohydrates that can't be broken further into smaller units on hydrolysis. For example Glucose, fructose, Ribose etc. oligosaccharides are the carbohydrates which on hydrolysis give two to ten units of monosaccharides eg.sucrose, Maltose, Lactose etc. polysaccharides product large number of monosaccharides units on hydrolysis eg. Starch, cellulose.
(i) Name the Linkage that holds the two units in the disaccharide.
(ii) Which disaccharide is found only in animals, not in plants?
(iii) Draw Haworth projection of α-D Glucose.
OR
What is Glycogen? How it is different from starch?
32. The Spontaneous flow of the solvent through a SPM from a pure solvent to a solution or from a dilute solution to a concentrated solution is called as Osmosis. The phenomenon of osmosis can be demonstrated by taking two eggs of the same size .In an egg the membrane below the shell and around the egg material is SPM.The outer hard shell can be removed by putting the egg in dilute HCI. After removing the hard shell, one egg is placed in distilled water. And the other in a saturated salt solution.After some time, the egg place in distilled water swells up while the egg placed in distilled water swells up while the egg placed in salt solution shrinks. The external pressure applied to stop the osmosis is termed as osmotic pressure. Reverse osmosis takes place when the applied external pressure becomes Larger than the osmotic pressure.
(i) What happens when RBC's are placed in 0.9% NaCl solution?
(ii) Which one of the following has higher osmotic pressure: 1M KCl or 1M urea ?
(iii) What is Reverse osmosis? Name one SPM which can be used in this Reverse osmosis.
OR
How the molecular mass of substance can be determined by the method based on measurement of osmotic pressure?
[Section-E:]
33.
(i) Discuss the nature of bonding in the following coordination entities on the basis of V.B.T.
(a) [CoF6]³⁻
(b) [Fe (CN) 6 ]⁴⁻
(ii) Write down the IUPAC each of the following complexes and indicated the oxidation state, electronic configuration, coordination number and magnetic moment of the complex K4 [Mn (CN)6].
OR
(i) What is spectrochemical series? Explain the difference between a weak field ligand and a strong field Ligand.
(ii) A Solution of [Ni(H2O)6]²⁺ is green but a solution of [Ni(CN)4]²⁻ is Colourless. Explain.
(iii) What will be the correct order for the wavelength of absorption in the visible region of the following: [Ni(NO2)6]⁴⁻,[Ni(NH3)6]²⁻,[Ni(H2O)6 ]²⁺
34. (i) An organic compounds (A) with molecular formula C8H8O forms an orange -red ppt with 2,4 DNP reagent and gives yellow ppt on heating with iodine in the presence of sodium hydroxide. It neither reduces Tollen's or Fehling 's reagent, nor does it decolourise bromine water or Baeyer's reagent. on drastic oxidation with chromic acid. It gives a Carboxylic acid (B) having molecular formula C7H6O2 identify the compound (A) and (B) explain the reaction involved.
(ii) Arrange the following Compounds in increasing order of their property as indicated:
(a) Acetaldehyde, Acetone, Di-tert-butyl ketone, Methyl tert - butyl Ketone (reactivity towards HCN)
(b) Benzoic acid, 4 - Nitro benzoic acid, 3,4-dinitro benzoic acid, 4-methoxybenzoic acid (Acid strength)
OR
(i) Prepare the following from benzene diazonium chloride:
(a) iodobenzene
(b) Fluorobenzene
(c) Benzene
(ii) Why Aniline does not show Friedal craft reaction.
35. (i)Write the Nernst equation and Calculate the EMF of the following cell at 298 K :
Mg(s) |Mg²⁺(0.001M)||Cu^ 2+ (0.0001M)|Cu(s) E°Mg²⁺/ Mg = - 2.37V
E°cu²⁺/Cu.=+0.34 V
(ii) Why does the Conductivity of a solution decrease with dilution.
OR
(i) Calculate the standard cell potential of galvanic cell in which the following reaction takes place. Also calculate the value of ∆rG° of the reaction:
2Cr(s)+3Cd²⁺(aq)→2Cr³⁺(aq)+3Cd(s)
E°cr³⁺/Cr = - 0.74V
E°Cd²⁺/Cd = - 0.4V
(ii) Define Kohlrausch's Law by taking suitable examples.
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