RBSE Class 12 Chemistry Model Paper 3 English Medium

RBSE Class 12 Chemistry Model Paper 3 English Medium are part of RBSE Class 12 Chemistry Board Model Papers. Here we have given RBSE Class 12 Chemistry Sample Paper 3 English Medium.

Board RBSE
Textbook SIERT, Rajasthan
Class Class 12
Subject Chemistry
Paper Set Model Paper 3
Category RBSE Model Papers

RBSE Class 12 Chemistry Sample Paper 3 English Medium

Time: 3¼ Hours
Maxim Marks: 80

General Instructions to the Examinees:

  1. Candidate must write first his/her Roll No. on the question paper compulsorily.
  2. All the questions are compulsory.
  3. Write the answer to each question in the given answer-book only,
  4. For questions having more than one part, the answer to those parts are to be written together in continuity.
  5. If there is any error/difference/contradiction in Hindi & English version of the question paper, the question of Hindi version should be treated valid.
  6. Question Nos. Marks Per Questions
    1 – 13 1
    14 – 24 2
    25 – 27 3
    28 – 30 4
  7. Question Nos. 21, 27, 28, 29 and 30 have internal choices.


Question 1.
What is the number of octahedral sites per sphere in fee structure? [1]

Question 2.
What happens to the freezing point of a solution when a non-volatile solute is dissolved in it? [1]

Question 3.
The coagulation of 10 ml of a colloidal gold sol is completely prevented by addition of 0.025 g of to it before adding 10 ml of 10% NaCl solution. What is the gold number of starch? [1]

RBSE Class 12 Chemistry Model Paper 3 English Medium

Question 4.
What is actinoid contraction? [1]

Question 5.
Why do transition elements show variable oxidation states? [1]

Question 6.
Which of the following ions are coloured in aqueous solution and why? [1]
Sc3+, V3+, Ti4+ , Mn2+

Question 7.
What is the oxidation state of Fe in the brown ring complex? [Fe(H2O)5NO] SO4. [1]

Question 8.
Give one use of iodoform and Freon-12 [1]

Question 9.
What happens when chlorobenzene is heated with CuCN at 475K. (Write the equation only). [1]

Question 10.
Give a test to distinguish phenol from carboxylic acid. [1]

Question 11.
Name the monomer used to prepare aliphatic biodegradable polymer, which is used in packaging and orthopedic devices. [1]

RBSE Class 12 Chemistry Model Paper 3 English Medium

Question 12.
Predict the number of optical isomers for the following compound CH2OH(CHOH)4CHO. [1]

Question 13.
Which class of synthetic detergent is present in hair shampoo? [1]


Question 14.
(a) How does doping silicon with boron increase the conductivity of silicon?
(b) What do you mean by Bravais lattices? [1 + 1=2]

Question 15.
(a) What is abnormal molecular mass of a solute? [1 + 1=2]
(b) Among 1(M) solution each of Na2SO4, KCl, glucose, and urea, which will have die highest boiling, point?

Question 16.
(a) Give the labeled diagram of a Galvanic cell. [1 + 1=2]
(b) Calculate the electrochemical equivalent of Ag. (Equivalent mass of Ag = 108).

Question 17.
What is the effect of dilution of specific conductance and equivalent conductance of a weak electrolyte? Explain. [2]

RBSE Class 12 Chemistry Model Paper 3 English Medium

Question 18.
(a) Out of C and CO, which is better reducing agent F or FeO in the upper part of the blast furnace (lower temperature).
(b) Why reducing agents like carbon and hydrogen are not used to reduce metallic oxides at high temperature. [1 + 1=2]

Question 19.
On the basis of valence bond theory account for the hybridisation, shape and magnetic property of cuprammonium ion. [2]

Question 20.
(a) How does chlorobenzene react with cone H2SO4 and (ii) Copper
(b) Write the equation for example of

  1. Kharasch reaction and
  2. Dow’s process. [2]

Question 21.
Why are aldehydes more reactive than ketones? [2]


Identify A, B and ‘C’ in the following reaction

Question 22.
A polymer sample contains 100 molecules having molecular mass of 15,000, 200 molecules having molecular mass of 10,000 and 150 molecules with molecular mass of 20,000. Calculate the weight average molecular mass of the polymer. [2]

Question 23.
(a) What is absolute and relative configuration?
(b) What do you mean by axis of symmetry? [1 + 1 = 2]

RBSE Class 12 Chemistry Model Paper 3 English Medium

Question 24.
(a) What is the difference between soft and hard detergent? [1 + 1=2]
(b) What is saponification of oils and fats?


Question 25.
(a) Differentiate between homogeneous and heterogeneous catalysis with one example each,
(b) What do you understand by catalytic promoter. Give an example. [2 + 1 = 3]

Question 26.
(a) Briefly discuss the replication of DNA. Can RNA replicate? Explain.
(b) What is genetic code? [2 + 1=3]

Question 27.
(a) Give chemical equations for each of the following reactions.

  1. Gattermann reaction
  2. Schmidt reaction

(b) An organic compound A upon reacting with NH3 gives B. On heating B gives C. In presence of Br2 and KOH ‘C’ gives CH3CH2NH2. What is A? [2 + 1 = 3]


(a) Give a chemical test to distinguish between

  1. aniline and ethylamine
  2. CH3CH2NH2 and CH3-NH CH3.

(b) Write the chemical equation for reaction of methylamine with carbon disulphide followed by heating with HgCl2. [1 ½+1 ½ = 3]

RBSE Class 12 Chemistry Model Paper 3 English Medium


Question 28.
(a) Derive integrated rate equation for a zero order reaction.
(b) The half-life period of a first order reaction is 60 mins. What percentage will be left after 120 mins? [2 + 2 = 4]



  1. What do you mean by half-life period of a reaction? [1 + 1 + 2 = 4]
  2. Write the unit of rate constant of zero order reaction.

(b) Write an equation which shows relation between rate constant (k), initial concentration (a) and half-life period of a zero order reaction.
(c) The rate constant of a first-order reaction is 60 s-1. How much time will it take to reduce the initial concentration to its \(\frac {1}{16}th\)value.

Question 29.
(a) Write the general electronic configuration of picogens. Write the chemical formula of four axides of N2.
(b) Write the chemical formulae of four oxides of nitrogen.
(c) Write the reaction of excess NH3 with chlorine.
(d) What is philosopher’s rings or vertex rings.


(a) Write a chemical equation for the preparation of SO2 industrially.
(b) What happens when SO2 is passed through water.
(c) Write reaction showing reducing property of SO2
(d) Draw a labeled diagram showing ring structure of rhombic sulphur. [1 + 1 + 1 + 1 = 4]

Question 30.
(a) Draw the structure of

  1. Hex-1-en-3-ol
  2. 3-amino pentan-2-ol [1 + 1 + 2 = 4]

(b) Why do alcohols have higher boiling points than haloalkanes of comparable molecular mass?
(c) Why is sulphuric acid not used during the reaction of alcohol with KI in the conversion of alcohol to alkyl iodide?


(a) What is the relative ease of dehydration of 1°, 2°, and 3° alcohols?
(b) Give an example of Bouveault Blanc reduction.
(c) How is phenolphthalein obtained? [1 + 1 + 2 = 4]

RBSE Class 12 Chemistry Model Paper 3 English Medium

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