Plus Two Chemistry Model Question Paper 3

Kerala Plus Two Chemistry Model Question Paper 3

Time: 2 Hours
Cool off time: 15 Minutes
Maximum: 60 Scores

General Instructions to candidates

• There is a ‘cool off time’ of 15 minutes in addition to the writing time of 2 hrs.
• Use the ‘cool off time’ to get familiar with the questions and to plan your answers.
• Read questions carefully before you answering.
• Read the instructions carefully.
• Calculations, figures, and graphs should be shown in the answer sheet itself.
• Malayalam version of the questions is also provided.
• Give equations wherever necessary.
• Electronic devices except non-programmable calculators are not allowed in the Examination Hall.

(Questions 1 to 7): Carry one score each. Answer all questions.

Question 1.
The polymer used in orthopaedic devices j and in controlled drug release is

Question 2.
Which one among the following is not an analgesic?

a. Ibuprofen
b. Naproxen
c. Aspirin
d. Valium

Question 3.
Addition of Grignard reagent to an aldehyde j or ketone gives an ;

a. anomer
b. ether
c. ester
d. alcohol

Question 4.
Following graph is a plot of the rate of a reaction vs concentration of the reactant, What is the order of the reaction?

Question 5.
How will the pH of brine ( aq. NaCl solution) effect when it is electrolysis?

Question 6.
Which stoichiometric defect in crystal increased the density of a solid?

Question 7.
Given an example of a material used for making semipermeable membrane for carrying out reverse osmosis.

(Questions 8 to 20) : Answer any ten. Each questions carries two scores.

Question 8.
a. Identify an analgesic from the following:
i. Equanil
ii. aspirin
iii. serotonin
iv. cimetidine
b. Differentiate between antiseptics and antibiotics.

Question 9.
a. Among the following which one is chlorine containing insecticide?
(i) DDT
(ii) Freon
(iii) Phosgene
(iv) Iodoform
b. Haloarenes undergo WurtzFitting reaction. What is WurtzFitting reaction?

Question 10.

Write the formulae of A and B in the above reaction.

Question 11.
Every substance has some magnetic properties associated with it. How will you account for the following magnetic properties?
i. Paramagnetic property
ii. Ferromagnetic property

Question 12.
Osmotic pressure is a colligative property and it is proportional to the molarity of the solution.
a. What is osmotic pressure?
b. The molecular mass of NaCI determined by osmotic pressure measurement is found to be half of the actual value. Account for it.

Question 13.
Aldol condensation reaction is a special reaction of aldehydes.
i. What is aldol condensation reaction?
ii. Write the structural formula of aldol formed from ethanol.

Question 14.
Synthetic rubber is a Vulcanisable rubber-like polymer.
i. Wite one example for synthetic rubber.
ii. Write the method of preparation of the above synthetic rubber.

Question 15.
A compound is formed by two elements P and Q. Atoms of Q (as anions) make hep lattice and those of the element P (as cations) occupy all the tetrahedral voids. What is the formula of the compound?

Question 16.
Write simple chemical tests and observations used to distinguish between the following compounds.
i. Propanal and propanone
ii. Phenol and benzoic acid

Question 17.
Calculate the osmotic pressure exerted to a solution prepared by dissolving 1.5 g of a polymer of molar mass 185000 in 500 ml of water at 37°C. [R = 0.0821 L atm K^-1 mol^-1]

Question 18.
Colligative properties can be used to determine the molecular mass of solutes in solutions.
a. What do you mean by coffigative property’?
b. For determining the molecular mass of polymers, osmotic pressure is preferred to other properties. Why?

Question 19.
The limiting molar conductivity of an electrolyte is obtained by adding the limiting molar conductivities of cation and anion of the electrolyte.
a. Name the above law.
b. What is meant by limiting molar conductivity?

Question 20.
Which are the monomers of Nylon6 and Nylon66?

(Questions 21 to 29): Answer any seven. Each questions carries three scores.

Question 21.
a. Explain how conductivity measurements help to determine the ionisation con start a weak electrolyte like acetic acid.
b. Explain the change of conductivity and molar conductivity of a solution with dilution?

Question 22.
a. Atomic sizes increase as we come down
a group, but in 4^th group of the periodic table Zr, Hf has almost the same atomic sizes. Why?
b. E° (Standard electrode potential) values generally become less negative as we move across a transition series, but E° values of Ni²⁺/Ni and Zn²⁺/Zn values are exceptions.

Question 23.
Phenols are more acidic than alcohols.
a. Name the product obtained when phenol is treated with chloroform in presence of NaOH.
b. Name the above reaction.
c. What is the product obtained when phenol is treated with conc.HNO₃?

Question 24.
a. Amines are versatile functional group useful in the preparation of many organic compounds. How can you convert?

b. A student tried to prepare nitro aniline by nitrating aniline with a cone. HNO₃ cone. H₂SO₄ mixture, but he got only m nitroaniline. Why?
c. Explain how to prepare nitro aniline from aniline?

Question 25.
Colloids exhibit certain special properties,
a. Name the property of colloid involved in j the construction of ultramicroscope?
b. Explain the above property.
c. What are the conditions to be satisfied to exhibit Tyndall effect?

Question 26.
Aromatic amines are important synthetic intermediates.
i. What are the products obtained when aniline is treated with Bromine water?
ii. How will you convert nitrobenzene to aniline?
iii. Write down the isocyanide test for the primary amines.

Question 27.
Carbohydrates can be divided into three major classes monosaccharides, oligosaccharides and polysaccharides.
a. What are polysaccharides?
b. Give two examples for polysaccharides.
c. What is invert sugar?

Question 28.
Antibiotics, antiseptics and disinfectants are antimicrobial drugs.
a. Give 2 examples of antibiotics.
b. Write one similarity between antiseptics and disinfectants.
c. Write one difference between antiseptics and disinfectants.

Question 29.
[Cr(NH₃)₄CI₂]Br is a coordination compound.
a. Identify the central metal ion of the above compound.
b. Name the ligands present in it.
c. What is the coordination number?

(Questions 30 to 33): Answer any three. Each questions carries four scores

Question 30.
Colligative properties are properties of solutions which depend on the number of solute particles irrespective of their nature.
a. Name the four important colligative properties.
b. What happens to the colligative properties when ethanoic acid is treated with benzene? Give reason.

Question 31.
The order of a chemical reaction can be zero and even a fraction, but molecularity cannot be zero or a non-integer.
i. What do you mean by the order of a reaction?
ii. What is molecularity of a reaction?
iii. The conversion of molecules ‘A’ to‘B’ follows second order kinetics. If concern traction of ‘A’ is increased to three times, how will it affect the rate of formation of ‘B’?

Question 32.
The geometry and magnetic properties of complexes can be explained by VB Theory. The octahedral complex [CO(NH₃)₆]³⁺ is diamagnetic, while the octahedral complex [COF₆]^3-is paramagnetic. Explain using VB theory?

Question 33.

a. What is its IUPAC name?
b. Explain the conversion of the above acid into the following.

Answers

Answer 1.
d

Answer 2.
Valium

Answer 3.
d

Answer 4.
Zero-order reaction

Answer 5.
It will increase due to the formation of NaOH.

Answer 6.
Interstitial defect

Answer 7.
Cellulose acetate

Answer 8.
a. ii. aspirin
b. Antiseptics are substances which prevent the growth of microorganisms or kill them but are not harmful to the living human tissues. Antibiotics are drugs used to treat infections in our body. it inhibits the growth of microorganisms.

Answer 9.
a. ii.DDT
b. When aryl halide is heated with an alkyl halide in the presence of sodium in dry ether, a halogen atom is replaced by an alkyl group and alkylarene is formed. This process is called Wurtz Fitting reaction.

Answer 10.

Answer 11.
i. Paramagnetic property is the property formed by the substance as it is early attracted by the magnetic field m.field). Magnetic alignments are in same direction, eg., O₂, Fe³⁺.
ii. ferromagnetic property is the property formed by the substance due to strongly attracted by the magnetic field. Magnetic alignments are in same direction, eg., CO, Ni.

Answer 12.
a. osmotic pressure is the external pressure squired to stop the flow of solvent mole ule from higher concentration to lower concentration through a semipermeable membrane. It is a colligative property.
b. dilution no. of molecules increases, therefore mass decreases. On dilution, laCI dissociates to two molecules? So a solar mass decreases to half.

Answer 13.
i. Idol condensation reaction. dehyde and Ketones having one hydrogen react in the presence of dilute skill to form aldol and Ketol, which no further reaction and release water molecule to form α, β unsaturated compound.

Answer 14.
i. Neoprene.
ii. By the polymerisation of chlorine

Answer 15.
No. of atoms of Q = N No. of atoms of P = 2N
∴ The ratio of atoms of P & Q = 21
∴ The formula = P₂Q

Answer 16.
i. Tollen’s test
ii. Iodoform test

Answer 17.

Answer 18.
a. Properties which depend on the number of particles and not on it nature are called colligative property
b. This is because in the osmotic pressure method, the pressure is measured at room temperature and molarity the solution is used instead of mole

Answer 19.
a. Kohlrausch’s law.
b. It is the molar conductivity of electrolytes at zero concentration or at infinite dilution.

Answer 20.
Nylon-6 Caprolactam
Nylon-66 Hexamethylenediamine and adipic acid

Answer 21.
a. The degree of dissociation can be determined by the equation, α = \(\frac { { \lambda }_{ m } }{ { \lambda }_{ 0 }^{ m } }\) To obtain ionisation constant, K_a, sub stitute a in the following equation, \({ K }_{ a }=\frac { { Ca }^{ 2 } }{ \left( 1-\alpha \right) }\) ;where C is the concentration a of acetic acid in moles/litre.
b. Conductivity of a solution decreases with a decrease in concentration as the number of ions present per unit volume of the solution actually decreases. The molar conductivity of electrolytes increases with a decrease in concentration.

Answer 22.
a. Due to lanthanoid contraction, size of 2nd series Zr and 3^rd series Hf elements are almost similar.
b. The exceptional behaviour of Ni is due to its high negative enthalpy of hydration. Since Zn has completely filled orbitals, it E? value is more negative than expected.

Answer 23.
a. Salicylaldehyde.
b. Reimer-Tiemann reaction.
c. Picric acid is formed.

Answer 24.

b. Due to the formation of anilinium ion, since -N⁺H₃ is a meta directing group, meta nitro aniline is obtained.
c. NH₂ group is protected from protonation by acetylation.

Answer 25.
a. Tyndall effect.
b. The phenomenon of scattering of light by colloidal particles when a beam of light is passed through it is called the Tyndall effect.
c.
i. The size of the colloidal particles and the wavelength of the light used sho could be comparable.
ii. There should be a very large difference between the dispersed phase arid I dispersion medium.

Answer 26.

iii. Carbylamine reaction.
1° amine on heating with chloroform j and ethanolic KOH form isocyanides.

Answer 27.
a. Polysaccharides give a large number of monosaccharide units on hydrolysis.
b. Starch and cellulose.
c. Sucrose solution is dextrorotatory. When it is subjected to hydrolysis, the resultant sugar-solution becomes levorotatory. This sugar is called invert sugar.

Answer 28.
a. Penicillin, ofloxacin.
b. Antiseptics and disinfectants are chemicals which prevent or kill the growth of microorganisms.
c. Antiseptics are applied to living tissues such as wounds, cuts, ulcers etc to kill microorganisms. Disinfectants are applied on floors, drainage system like nonliving materials to kill microorganisms.

Answer 29.
a. Chromium.
b. Ammonia, Chloride,
c. 6

Answer 30.
a.
1. Lowering of vapour pressure
2. The salvation of boiling point
3. Depression in freezing point
4. Osmotic pressure.
b. Due to an association of molecules, the ‘ number of particle decreases and colligative property decreases. Molecules of ethanoic acid dimerise in benzene due to hydrogen bonding.

Answer 31.
i. Order of a reaction is the sum of the powers of the concentration terms of the reactants as expressed in the rate equation.
ii. It is the no. of molecules of the reactants that collide simultaneously to bring about the chemical reaction.
iii. r = K. [A]²
r, = K. [3A]² = 9. K [A]²
∴ Rate increases by 9 times.

Answer 32.
The outer electronic configuration of cobalt is 3d⁷ 4s². In this complex, cobalt is in the +3 oxidation state. So electronic configuration of CO³⁺ is 3d⁶ 4s° is

Ammonia is a strong ligand. Therefore pairing of electrons takes place,

There are six ammonia molecules acting as ligands. So there should be six vacant orbitals for Co³⁺. Hence the metal ion undergoes d2sp3 hybridisation. Since there are no unpaired electrons, the complex is diamagnetic. [COF₆]^3- Here also cobalt is in the +3 oxidation state.

But P is a weak ligand. So pairing does not take place. Hence in metal ion undergoes sp³d² hybridisation. There are four unpaired electrons present, .. the complex is paramagnetic.

Answer 33.
a. 3,4dinitrobenzoic acid,

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