RBSE Class 12 Chemistry Model Paper 4 English Medium

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RBSE Class 12 Chemistry Model Paper 4 English Medium are part of RBSE Class 12 Chemistry Board Model Papers. Here we have given RBSE Class 12 Chemistry Sample Paper 4 English Medium.

Board RBSE
Textbook SIERT, Rajasthan
Class Class 12
Subject Chemistry
Paper Set Model Paper 4
Category RBSE Model Papers

RBSE Class 12 Chemistry Sample Paper 4 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.

SECTION-A

Question 1.
Which type of solids have isotropic property? [1]

Question 2.
The liquids A and B boil at 145°C & 190°C respectively. Write the solution that has higher vapour pressure at 80°C. [1]

Question 3.
How will you obtain a colloidal solution of arsenious sulphide? [1]

RBSE Class 12 Chemistry Model Paper 4 English Medium

Question 4.
Silver atom has completely filled d-orbitals (4d10) in its ground, state, even then it is a transition element. How? [1]

Question 5.
Why the second and third members in each group of the transition elements have very similar properties? [1]

Question 6.
Atomic size of 3d series elements from Cr to Cu is almost same. Give reason. [1]

Question 7.
Arrange the following ions in the increasing order of crystal field splitting energy. [1]
[CrCl6]3-, [Cr(CN)6]3- [Cr(NH3)6]3-

Question 8.
Write the order of decrease of boiling point of alkyl halides. [1]

Question 9.
Chloroform on warming with silver powder gives an alkyne. Write the formula and IUPAC name of the alkyne. [1]

Question 10.
Give the chemical reaction when ethanol is heated with HI and Red P under pressure. [1]

RBSE Class 12 Chemistry Model Paper 4 English Medium

Question 11.
What is the function of sulphur in vulcanization of rubber? [1]

Question 12.
How many stereoisomers are possible for 2, 3-dichloro butanoic acid? [1]

Question 13.
Write the name of one drug for treatment of typhoid and pneumonia. [1]

SECTION-B

Question 14.
(a) How does doping increase the conductivity of semiconductors? [1 + 1=2]
(b) What is the effect of temperature on the conductivity of

  1. Semiconductors
  2. Metallic conductors?

Question 15.
(a) Between 2 M glucose and 1 M glucose which one has lower freezing point?
(b) 1.0 g of a non-electrolyte solute dissolved in 50 g benzene lowered the freezing point of benzene by 0.40 K. Calculate molecular mass of solute (kf = 5.12 k kg mol-1) [1 + 1 = 2]

Question 16.
(a) Describe the construction of lead storage battery.
(b) Write the reaction in this cell when it works to produce electricity. [1 + 1 = 2]

RBSE Class 12 Chemistry Model Paper 4 English Medium

Question 17.
Calculate the equilibrium constant for the reaction
Cu(s) + 2Ag+(aq) ⇌ Cu2+(aq) + 2Ag(s)

(Given E0Ag+|Ag = 0.80V & E0Cu2+|Cu = 0.34V)

Question 18.
(a) An ore of Galena is contaminated with zinc blende (ZnS). Name a chemical which can concentrate galena selectively by froth floatation process and how?
(b) What is the role of collectors in froth-floatation process? [1 + 1 = 2]

Question 19.
[Cr(NH3)6]3+ is paramagnetic while [Ni(CN)4]2 is diamagnetic give reason [2]

Question 20.
(a) Between chlorobenzene and chloromethane which one is more reactive towards nucleophilic substitution reaction give reason.
(b) Write the reason of oxidation of chloroform to phosgene. [2]

Question 21.
Why do aldehydes have lower boiling points than the corresponding alcohols? [2]

OR

Write the mechanism of nucleophilic attack on the carbonyl group of an aldehyde. [2]

RBSE Class 12 Chemistry Model Paper 4 English Medium

Question 22.
Give the name and structure of the monomers of bakelite. State whether bakelite is thermosetting or thermoplastic polymer. Give two uses of bakelite. [2]

Question 23.
(a) B.P. of cis-but-2ene is higher than that of transi-but-2-ene. Give reason.
(b) Show the axial and equatorial H-atoms in cyclohexane. [1 + 1=2]

Question 24.
(a) How is vat dye applied on fabrics? [1 + 1=2]
(b) What are direct dyes, give two examples.

SECTION – C

Question 25.
(a) Describe the preparation of colloidal solution of Fe(OH)3 by peptisation.
(b) What is aerosol? Give an example.
(c) Draw the labeled diagram of Bredig’s arc method. [1 + 1 + 1 = 3]

Question 26.
(a) Discussion the classification of proteins on the basis of molecular structure. [1 + 2 = 3]
(b) What are ultimate products of digestion of proteins and what is the biological function of hemoglobin?

Question 27.
(a) How will you convert [2 + 1 = 3]

  1. Aniline to o- and p-nitroaniline.
  2. Acetic acid to ethanamine.

(b) Which product is formed when aniline is first diazotized and then reacted with phenol in alkaline medium.

OR

(a) How will you convert

  1. methyl amine to ethylamine?
  2. ethylamine to methylamine.

(b) Which of the followings should be most volatile? [2 + 1=3]
CH3CH2CH2NH2, (CH3)3N,

RBSE Class 12 Chemistry Model Paper 4 English Medium

SECTION – D

Question 28.
(a) What do you mean by molecularity of a reaction? Give an example of a reaction in which molecularity is different from order of reaction.
(b) The rate constant of a reaction zero order is 0.0030 mol L-1 S-1. How long will it take for the initial concentration to fall from 0.10 M to 0.075 M? [2 + 2 = 4]

OR

(a) Define pseudo-first order reaction. Give two examples of it.
(b) The initial concentration of N2Os in a first order reaction
N2O5(g)→ 2NO2(g) + \(\frac {1}{2}\) O2(g) was 1.24 x 10-2 mol L-1 at 2.98 K. The concentration of N2O5 after 60 minutes was 0.2 x 10-2 mol L-1. Calculate the rate constant of the reaction.

Question 29.
Write chemical equation for the following reaction

  1. Ammonia reacts with atmospheric oxygen in presence of catalyst
  2. Sulphuric acid reacts with SO2
  3. Ammonia reacts with excess chloride
  4. Sulphuric acid reacts with metallic copper.

OR

(a) Why are all five bonds of PCl5 not equivalents? Explain
(b) Write the chemical formula of four oxyacids of chlorine.
(c) Write the general electronic configuration of noble gases. Which element of this group is useful in magnetic resonance imaging (MRI)?
(d) Write the reaction fo PCl3 with C2H5OH. [1 + 1 + 1 +1 = 4]

Question 30.
(a) Write two uses of alcohol. [1+ 1 + 1 + 1 = 4]
(b) Write the formula of ethylene glycol and give two uses of it.
(c) Write the IUPAC name of glycerol. Menton two of its uses.
(d) What is the IUPAC name of m-cresol and o-cresol.

OR

(a) How will you distinguish between phenol and carboxylic acid? (Give one chemical test)
(b) What happens when phenol is heated with ammonia in presence of anh. ZnCl2?
(c) Among acetone, ethanol, Propan-2-ol and methanol, which one does not give iodoform test?
(d) Arrange phenol, p-nitrophenol and m-nitrophenol in the decreasing order of acidity.

RBSE Class 12 Chemistry Model Paper 4 English Medium

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