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Maharashtra 2020
class 12
Chemistry
Series: J-346 SET - E Time allowed: 3 hours Maximum Marks: 70
General Instructions:
The question paper is divided into four sections.
(1) Section A: Q. No 1 concludes Ten multiple choice type of questions carrying One mark each.
Q. No 2 contains Eight very short answer type of questions carrying One mark each.
(2) Section B: Q. No. 3 to Q. No. 14 are Twelve short answer type of questions carrying Two marks each (Attempt any Eight)
(3) Section C: Q. No 15 to Q. 26 are Twelve short answer type of questions carrying Three marks each (Attempt any Eight)
(4) Section D: Q. No 27 to Q. No. 31 are Five long answer type of questions carrying Four marks each (Attempt any Three) (5) Use of log table is allowed. Use of calculator is not allowed.
(6) Figures to the right indicate full marks.
(7) For each MCQ. Correct answer must be written along with its alphabet. e.g. (a) ………/ (b) ………./ (c) ………/ (d) ………. etc.
(8) Physical constant:
Avogadro’s Number = NA = 6.022 x 1023
SECTION - A
Q.1. Select and write correct answer of the following questions: [10]
1. Identify synthetic polymer amongst the following: (a) Linear (b) Jute
(c) Silk (d) Terylene
2. Which among the following hydrides is NOT a reducing agent? (a) H2O (b) H2S
(c) H2Te (d) H2Se
3. During oxidation of ferrous sulphate using mixture of dil. H2SO4 and potassium dichromatic, oxidation state of chromium changes from ______.
(a) +6 to +2 (b) +6 to +3
(c) +6 to +1 (d) +6 to +4
4. Identify complex ion in which effective atomic number of the central metal ion is 35.
(Given At. Number of Co = 27, Fe = 26, Zn = 30)
(a) [Zn(NH3)6]2+
(b) [Zn(CN)6]4-
(c) [Zn(CN)6]3-
(d) [Co(NH3)6]3+
5. Conversion of methyl chloride into methyl fluoride is known as ______.
(a) Finkeltein reaction (b) Swarts reaction
(c) Williamson’s synthesis (d) Wurtz reaction
6. The number of moles of methyl iodide required to prepare tetramethyl ammonium iodide from 1 mole of methyl amine leave:
(a) 1 (b) 2
(c) 3 (d) 4
7. Name the reagent which on reaction with glucose confirms the presence of five hydroxyl groups in glucose:
(a) Hydroxyl amine
(b) Bromine water
(c) Dilute nitric acid
(d) Acetic anhydride
8. The number of moles of methyl iodide required to prepare tetra methyl ammonium iodide from 1 mole of methyl amine leave:
(a) Codeine (b) Equanil
(c) Penicillin (d) Valium
9. The number of atoms per unit cell body centered cube is: (a) 1 (b) 2
(c) 4 (d) 6
10. Calculate the work done during the reaction represented by the following thermochemical equation at 300 K:
CH4 + 2O2 CO2+2H2O
(g) (g) (g) (l)
(R = 8.314 JK-1mol-1)
(a) +4.988 KJ (b) -4.988 KJ
(c) -49.88 KJ (d) +49.88 KJ
Q.2. Answer the following questions: [8]
(i) What is the concentration of dissolved oxygen at 500C under pressure of one atmosphere if partial pressure of oxygen at 500C is 0.14 atm.
(ii) Write structural formula of the alcohol that results when acetaldehyde is reacted with CH3MgBr in the presence of dry ether and the product is hydrolysed.
(iii) Write the chemical reaction for preparation of acetic anhydride using acetic acid.
(iv) Write the chemical reaction involved in the formation of ethyl amine using acetaldoxime.
(v) What is electrometallurgy?
(vi) For the reaction:
N2O4 2NO2
(g) (g)
+ + -1 (ΔH =+57.24KJ,ΔS =+175.8JK )
At what temperature the reaction will be spontaneous? (vii) The standard e.m.f. of the following cell is 0.463 V Cu | Cu++ || Ag+ | Ag
(s) (1M) (1M) (s)
If the standard potential of Ag electrode is 0.800 V, what is the standard potential of Cu Electrode?
(viii) Write the mathematical relation between half life of zero order reaction and its rate constant.
SECTION – B
Attempt any EIGHT of the following questions: [16] Q. 3. State and explain Hess’s law of constant heat summation.
Q. 4. Write the cell reaction and calculate E0 cell of the following electrochemical cell:
Al | Al3+ || Zn2+ | Zn
(s) (aq.) (aq.) (s)
(1M) (1M)
E0Al = -1.66V
E0Zn = -0.76V
Q. 5. Distinguish between order and molecularity of a reaction. Q. 6. Write two uses of each of the following:
(a) Helium
(b) Neon
Q. 7. Write the name and chemical formula of one ore of zinc. Define : Quatermary ammonium salt.
Q. 8. What is the action of acidified potassium dichromate on the following:
(a) KI
(b) H2S
Q. 9. Define optical activity. How many optical isomers are possible for glucose?
Q. 10. Explain continuous etherification process for the preparation of diethyl ether.
Q. 11. Identify ‘A’ and ‘B’ in the following reaction:
Zn - Hg
+ CH3COCl A B + H2O AlCl3
-HCl
Conc. HCl
Q. 12. Write Haworth projection formula of
α - D - (+) - glucopyranose
Define hormones.
Q. 13. Classify the following solids into different types: (a) Silver (b) P4
(c) Diamond (d) NaCl
Q. 14. Define:
(a) Molality
(b) Osmotic pressure
SECTION – C
Attempt any EIGHT of the following questions: [24]
Q. 15. Define flux.
Write a note on leaching process.
Q. 16. Draw the structure of sulphurous acid.
Explain why nitrogen does not form pent halides.
Q. 17. Write the general electronic configuration of lanthanoids.
Why are most of the compounds of transition metals coloured?
Q. 18. Calculate the effective atomic number (e.a.n.) of copper in [Cu(NH3)4]2+.[Z of Cu = 29]
Explain ionisation isomerism in coordination compounds with a suitable example.
Q. 19. Write the chemical reactions of chlorobenzene with respect to:
(a) Sulphonation
(b) Acetylation
(c) Nitration
Q. 20. How is ethanol prepared from the following compounds? (a) Ethanol
(b) Ethene
(c) Bromoethane
Q. 21. How primary, secondary and tertiary aitroalkanes are distinguished using HNO2?
Q. 22. What are monosaccharides? Explain denaturation of proteins. Q. 23. Define non-biodegradable polymer.
Write the preparation of terylene.
Q. 24. What are soaps? How are soaps prepared?
Define antiseptic.
Q. 25. Unit cell of a metal has edge length of 288 pm and density of 7.86 g cm-3. Determine the type of crystal lattice.
[Atomic mass of metal = 56 g mol-1]
Q. 26. Define instantaneous rate of reaction.
Explain pseudo first order reaction with suitable example. SECTION – D
Attempt any THREE of the following questions: [12] Q. 27. Define the terms:
(a) Electrochemical series
(b) Corrosion
Write two applications of electrochemical series. Q. 28. Explain interhalogen compounds.
How is oxygen prepared from the following compounds? (a) KClO4
(b) PbO2
Q. 29. Explain the mechanism of aldol addition reaction. Mention two uses of carboxylic acids.
Q. 30. Derive the mathematical expression between molar mass of a non-volatile solute and elevation of boiling point.
State and explain van’t Hoff-Avogadro’s law. Q. 31. Define:
(a) Reversible process.
(b) Standard empathy of combustion Calculate the enthalpy change for the reaction: N2(g)+3H2(g) 2NH3(g)
The bond enthalpies are:
|
Bond
|
N = N
|
H - H
|
N - H
|
|
+ -1 ΔH KJmol
|
946
|
435
|
389
|
