CBSE Set Set1 Chemistry Sample Test Papers For Class 12th for students online

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Chemistry Class - XII  (CBSE)
You are on Set 1 questions 1 to 20

Q.1 What is the physical significance of the lines in the following depiction of atomic orbitals? (Mark 1)

Q.2 An ionic compound AB2 possesses CaF2 type crystal structure. Write the co-ordination numbers of A2+ and B- ions in the crystals of AB2. (AB2+ = 8, B- = 4 ) (Mark 1)

Q.3 How many state of a thermodynamic system be defined? (Mark 1)

State Kohlrausch's law for electric conductance of an electrolyte at infinite dilution. (Mark 1)

Q.5 For the reaction 3N2 (g) + H2 (g) ---- 2NH3 (g), how are the rate of reaction expression -d[H2]/ dt and d[NH3]/dt interrelated? (Mark 1)

Q.6 Mention the use of fromalin in industry.
 (Mark 1)

For an amine RNH2 write the expression for Kb to indicate its base strength. (Marks 1)

Q.8 What is responsible for the blue colour of a solution of an alkali metal in liquid ammonia? (Mark 1)

Q.9 Why do colloidal solution exhibit Tyndall effect? (Mark 1)

Q.10 Write any one characteristics feature of enzymatic catalysts. (Mark 1)

Q.11 Account for the following :
(i) Silicon is an insulator but silicon doped with phosphorous acts as a semiconductor.
(ii) Some of the glass objects recovered from ancient monuments look milky instead of being transparent. (Mark 2)

Give an example each of miscible liquid pairs showing positive and negative deviation from Raoult's law. Give one reason each for deviation.
 (Mark 2)

Q.13 Starting with thermodynamic relationship E = q - P V and H =E + PV derive the relationship H = qp (Mark 2)

Q.14 From the data given below at 298 K for the reaction :
CH4 (g) + 2O2 (g) ------ CO2 (g) + 2H2O (l)
Calculate the enthalpy of formation of CH4 (g) at 298 K.
Enthalpy of reaction = - 890.5 kJ
Enthalpy of formation of CO2 (g) = - 393.5 kJ mol-1
Enthalpy of formation of H2O (l) = - 286.0 kJ mol-1 (Mark 2)

Q.15 Give the IUPAC names of :

 (Mark 2)

Q.16 Give explanation for the following observation :
(i) An ether would possess a dipole moment even if the alkyl groups present in it are identical.
(ii) Towards nucleophilic reagents aldehydes are more reactive tan ketones.
 (Mark 2)

Q.17 For the following conversion reaction write the chemical equations :
(i) Ethyl isocyanide to ethylamine
(ii) Aniline to N-phenylthanamide(Mark 2)

Q.18 Account for the following :
(i) Ammonolysis of alkylhalides does not give a corresponding amine in pure state.
(ii) If -NO2 or -COOH groups is attached to a carbon of benzene ring, electrophilic substitution becomes difficult. (Marks 2)

Q.19 The sum of first and second ionisation energies and those of third and fourth ionisation energies of nickel and platinum are given below :


I E + IE2(MJ mol-1) I E3 + IE4(MJ mol-1)
2.66 6.70

Taking these values into account write :
(i) The most common oxidation state are for Ni and Pt and its reason.
(ii) The name of metal (Ni and Pt) which can form compound in +4 oxidation more easily and why. (Marks 1)

Q.20 (i) Of the ions Ag+, Co2+ and Ti+, which ones will be coloured in aqueous solution (Atomic numbers : Ag = 47, Co = 27, Ti = 22)
(ii) If each one of the above ionic species is in turn place in a magnetic field,
How will ir respond and why? (Marks 2)

Q.21 Among ionic species, Sc3+, Ce2+ and Ti4+, which ones will be occurred in aqueous solution? (Atomic number : Sc = 21, Ce = 58, Eu = 63) (Marks 2)

Q.22 Explain the following processes with a suitable example in each case :
(i) Chain - growth polymerisation
(ii) Step - growth polymerisation (Marks 2)

Q.23 Given an example of each, differentiate between multi-molecular and macromolecular colloides. (Marks 2)

Q.24 What are polysaccharides? Name one of the. How is it important for us. (Marks 2)

Q.25 What do you understand by the statement : "ATP molecules are the currency of energy metabolism in a cell." (Mark 2)

Q.26 Name the broad spectrum antibiotic and state two diseases for which it is prescribed. (Mark 2)

Q.27 The ionisation energy of hydrogen atom in ground state is 1312 kJ mol-1. Calculate the wavelength of radiation emitted when the electron in this atom makes a transition from n = 2 state to n = 1.
(Planks constant, h = 6.63 x 10-34 Js, velocity of light = 3 x 1010 cm s-1 and Avogadro number, NA = 6.02 x 1023 mol-1) (Marks 3)

Q.28 On dissolving 3.24g of sulphur in 4.0g of benzene boiling point of solution was higher than that of benzene by 0.81 K. Kb value for benzene is 2.53 K kg mol-1. What is the molecular formula of sulphur ? (Atomic mass of sulphur = 32 g mol-1) (Marks 3)

Q.29 Calculate the cell emf and G for the cell reaction at 25oC for the cell
Zn (s) | Zn2 + (0.0004 M) || Cd2+ (0.2 M) | Cd (s)
Eo values at 25o C : Zn2+ / Zn = - 0.763 V ; Cd2+/ Cd = -0.403 V;
F = 96500 C mol-1; R = 8.314 JK -1. (Marks 3)

Q.30 Describe how important functions each of the elements P, B and S in green plants and also write the deficiency symptoms of any two of them.
 (Marks 3)

Q.31 Describe the following :
(i) Optical isomerism.
(ii) Magnetic behaviour of [Ni(CN)4]2- ion. (At. No. of Ni =28)
(iii) Preparation of tetrabutyl tin (Marks 3)

Q.32 (i) What is nuclear fission reaction
(ii) Describe the basic principle of a nuclear reactor? (Marks 3, 2)

Q.33 (a) Write chemical equation and reaction conditions for the conversion of :
(i) Propane to 1-bromo-propane
(ii) Chlorobenzene to phenol
(iii) 2-propanol to iodoform
(b) How is glycerol obtained commercially, state its two uses. (Mark 3)

Q.34 (a) Account for the following observation :
(i) In several chemical properties lithium resembles magnesium.
(ii) +1 oxidation state of thallium (atomic no 81) is more stable than its +3 oxidation state.
(iii) Boron chloride exists as a monomer while in the same group anhydrous aluminium chloride exists as adimer.
(b) Complete and balance the following chemical equation :
(i) NH3 + NaOCl ----
(ii) XeF4 + SbF5 (Mark 3, 2)