Grade :12 Chemistry FM:75 PM:30 Author : NEB important questions Time:3 hours Group : “A” Attempt any 15 questions.(2*15 =30)
1)Define pH of a solution.Write relation between pH and pOH.
2)Mention one example of each :Trigonal and sp hybridization.
3)X gm of caustic soda requires 50 ml of 5 N HCl solution for complete neutralization.Find value of X.
4)Why is aqueous solution of Sodium carbonate basic?Explain.
5)Why is trichloroacetic acid stronger than chloroacetic acid?
6)Convert phenol to acetanalide.
7)Why does zinc become dull in moist air?
8)Define electrolytic conductance.Write its unit.
9)What happens when:
a)Phenol is treated with chloroform and aq.NaOH.
b)Chlororbenzene is heated with chloral in prescence of conc Sulphuric acid.
10)Suggest a chemical test to identify phenol and ethanol.
11)Show your familiarity with williamson's synthesis.
12)The half life of a first order reaction is 30 minutes.Calculate rate constant of the reaction.
13)Point out differences between end point and equivalence point.
14)Acetamaide is amphoteric in nature.Justify it.
15)Write the action of Heat and cobalt nitrate on zinc oxide.
16)Name two important ores of copper with formula.
17)Define heat of combustion and enthalpy of formation.
18)Give an example and use of homo polymer and co polymer.
19)What is an azodye?Give an example.
20)How can you say that life is impossible without Hydrogen bond?
21)What happens when oil is hydrogenated.
22)Convert calomel into corrosive sublimate and vice versa.
Group (B) Solve any 5 questions (5*5 =25)
23)An alkylhalide (X)when reacted with KCN gives a compound ,which on acidic hydrolysis gives a compound (Z).The compound Z reacts with calcium carbonate to produce a compound (A).The compound (A) when heated strongly gives propanone.Identify compound A, X,Y,Z.Give equations of all reactions.
24)How would you obtain primary,secondary,tertiary alcohols by using Grignard's reagent?Also state what happens when they are oxidized.( 3+2 )
25)Difference between Methanl and ethanal.
26)The standard reduction potential of copper and silver electrodes are +0.34V and +0.80 V respectively. a)Identify anode and cathode.(0.5+0.5) b)Calculate standard cell potential. (1) c)Write balance reaction taking at anode and cathode.(1) d)Write overall cell reaction.(1) e)Show it in figure.(1)
27)Describe the extraction of pure zinc from its sulphide ore.
28)State and explain the second law of thermodynamics.How does a free energy change depend on the equilibrium constant.
29)Define rate of reaction.Explain the effect of temperature and catalyst on the rate of reaction.
Group “C”
Solve any two questions. (2*10=20 )
30)How is pure aniline prepared in lab?Convert aniline into :
a)Phenol b)phenyl isocyandie c)sulphanilic acid d)chlorobenzene
31)i)Starting from the ethanol how would you prepare the following? a)ethnae b)ethyl iodide c)ethyne d)ethanoic acid e)iodoform
ii)How is ethoxy ethane prepared in lab and purified ?
32)i)Define the terms : a)Acidimerity b)Formality c)Normality d)Molality e)Indicator
ii)3 g of trivalent metal was completely dissolved with 750 ml of 1N HCl.The residual solution further required 1000 ml of N/2 NaOH for the complete neutralization.Find the atomic mass of the metal.
iii)Calculate molarity of 5% Sulphuric acid solution.
33)Write short notes on any two : a)Manufacture of steel by open hearth process. b)Common ion effect c)lab preparation of methanoic acid. d)Chemistry on blue vitriol.
Some of the Important Question that you mustn’t miss before the start of exam :
Unit 1 : VSEPR Theory
Unit 5 : Numerical Questions from this unit [5 marks, SQ]
Unit 6 : Gibbs Free Energy,….
Unit 7 : Numerical Question [Q. 30, 10 marks]
Unit 8 : Lab. Preparation of [Formic Acid] & [Anhydrous Methonoic Acid]
Unit 9 : Lab. Preparation of [Trichloromethane] & [Chloroform]
Unit 10 : Conversions || Victor Mayer’s Method
Unit 11 : Lab. Preparation of [Ethoxyethane or diethyl ether]
Unit 12 : Identification Type (if asked)
Unit 13 : Lab. Preparation of [Anhydrous formic acid]
Unit 14 : Lab. Preparation of [Nitrobenzene]
Unit 15: Hoffmann’s Method || Conversion (from Aniline) || Lab. Preparation [Aniline]
Unit 18: Extraction of Zinc || Chemistry of [White Vitriol] & [Zinc White]
Unit 18: Extraction of Mercury || Chemistry of Calomel
Unit 18: Manufacture of Steel by [Bessemer’s Process] & [Open-Hearth]
Some other Important Reactions:
Williamson’s Synthesis, Aldol, Cannizzaro’s Reaction, Perkin, Riemer-Tieman, Fidel craft Alkylation / Acylation, Fermentation, Sand Meyers
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