Question

An organic compound A having molecular formula \(C_6\)\(H_6\)O turn blue litmus solution into red but does not react with sodium bicarbonate, but when treated with bromine water then form a white ppt of compound B. when compound A react with chloroform in presence of aqueous caustic soda solution at 340K then form two compound C and D. When compound A treated with caustic soda then form compound E compound E when treated with methyl halide then form compound F. Read the above passage carefully and answer the following questions: (i) The name of compound is: (a) 2-methyl propene-2-ol (b) 2-methyl phenol (c) 2,4,6-tribromophenol (d) Butane 1-ol (ii) Which are isomers of each other (a) A and C (b) B and C (c) C and D (d) D and E (iii) The IUPAC name of compound F is (a) Anisole (b) Methoxybenzene (c) Salicylaldehyde (d) 2-methyl propene-2-ol (iv) When compound E treated with ethyl iodide then ...... form. (a) Ehoxybenzene (b) Ethoxy hexane (c) Propoxypropane (d) Benzaldehyde (v) On oxidation with sodium dichromate and conc \(H_2\)\(SO_4\) phenol gives (a) Benzaldehyde (b) p-Benzoquinone (c) o-Benzoquinone (d) m-benzoquinone

Group 16 elements are called chalcogens i.e., ore forming elements (oxygen, sulphur, selenium etc.) because most of the ores are oxides and sulphides. Oxygen is gas where as other elements of group 16 are solids. Oxygen shows anomalous behaviour. Oxygen is diatomic where is sulphur exists as \(S_8\) which has crown shaped structure. It shows allotropy. Sulphur is present in onion and garlic that is why they have pungent smell. Sulphur is used for manufacture of sulphuric acid which is called ‘King of chemicals’, used in fertilizer, detergents, dyes and drugs. The following questions are multiple choice questions. Choose the most appropriate answer. 1) Group 16 elements are also known as a) Noble elements b) Halogens c) Pnictogens d) Chalcogens 2) Acidic character of hydrides of group 16 elements is in the order a) \(H_2\)O < \(H_2\)S < \(H_2\)Se < \(H_2\)Te b) \(H_2\)S < \(H_2\)Se < \(H_2\)Te < \(H_2\)O c) \(H_2\)O < \(H_2\)Se < \(H_2\)Te < \(H_2\)S d) \(H_2\)O < \(H_2\)S < \(H_2\)Te < \(H_2\)Se 3) Hybridisation of S in \(SF_4\) and geometry of \(SF_4\) are respectively a) \(sp^3\)d, trigonal pyramidal b) \(sp^3\)d, see saw c) \(sp^3\), tetrahedral d) \(dsp^2\), square planner 4) Which is not an acidic oxide? a) \(CO_2\) b) \(SO_2\) c) \(Na_2\)O d) \(Cl_2\)\(O_7\) 5) Which is not correct about allotropes of sulphur a) The stable form at room temperature is rhombic sulphur b) Monoclinic sulphur is stable above 369 K and transforms into rhombic sulphur below it c) At 369 K both the forms are stable d) Monoclinic sulphur is soluble in \(CS_2\) while rhombic sulphur not

Read the passage given below and answer the following questions: In an ideal crystal, there must be regular repeating arrangement of the constituting particles and its entropy must be zero at absolute zero temperature. However, it is impossible to obtain an ideal crystal and it suffers from certain defects called imperfections. In pure crystal, these defects arises either due to disorder or dislocation of the constituting particles from the normal positions or due to the movement of the particles even at absolute zero temperature. Such defects increase with rise in temperature. In addition to these certain defects arise due to the presence of some impurities. Such defects not only modify the existing properties of the crystalline solids but also impart certain new characteristics to them. Answer the following MCQs by choosing the most appropriate options: 1) AgCl is crystallized from molten AgCl containing a little \(CdCl_2\). The solid obtained will have (a) cationic vacancies equal to number of \(Cd^{2+}\) ions incorporated. (b) cationic vacancies equal to double the number of \(Cd^{2+}\) ions. (c) anionic vacancies. (d) neither cationic nor anionic vacancies. 2) Lattice defect per \(10^{15}\) NaCl is 1. What is the number of lattice defects in a mole of NaCl? (a) 6.02 × \(10^{23}\) (b) 6.02 × \(10^8\) (c) \(10^{14}\) (d) None of these 3) The ionic substances in which the cation and anion are of almost similar size shows (a) non-stoichiometric defect (b) Schottky defect (c) Frenkel defect (d) all of these 4) Which of the following gives both Frenkel and Schottky defect? (a) AgCl (b) CsCl (c) KCl (d) AgBr

The solubility of gases increases with increase of pressure. William Henry made a systematic investigation of the solubility of a gas in a liquid. According to Henry’s law “the mass of a gas dissolved per unit volume of the solvent at constant temperature is directly proportional to the pressure of the gas in equilibrium with the solution”. Dalton during the same period also concluded independently that the solubility of a gas in a liquid solution depends upon the partial pressure of the gas. If we use the mole fraction of gas in the solution as a measure of its solubility, then Henry’s law can be modified as “the partial pressure of the gas in the vapour phase is directly proportional to the mole fraction of the gas in the solution”. Answer the following MCQs by choosing the most appropriate options: (i) Henry’s law constant for the solubility of methane in benzene at 298 K is 4.27 × \(10^5\) mm Hg. The solubility of methane in benzene at 298 K under 760 mm Hg is (a) 4.27 × \(10^{-5}\) (b) 1.78 × \(10^{-3}\) (c) 4.27 × \(10^{-3}\) (d) 1.78 × \(10^{-3}\) (ii) The partial pressure of ethane over a saturated solution containing 6.56 × \(10^{-2}\) g of ethane is 1 bar. If the solution contains 5.00 × \(10^{-2}\) g of ethane then what will be the partial pressure (in bar) of the gas? (a) 0.762 (b) 1.312 (c) 3.81 (d) 5.0 (iii) KH (K bar) values for Ar(g), \(CO_2\)(g), HCHO(g) and \(CH_4\)(g) are 40.39, 1.67, 1.83 × \(10^{-5}\) and 0.413 respectively. Arrange these gases in the order of their increasing solubility. (a) HCHO < \(CH_4\) < \(CO_2\) < Ar (b) HCHO < \(CO_2\) < \(CH_4\) < Ar (c) Ar < \(CO_2\) < \(CH_4\) < HCHO (d) Ar < \(CH_4\) < \(CO_2\) < HCHO (iv) When a gas is bubbled through water at 298 K, a very dilute solution of the gas is obtained. Henry’s law constant for the gas at 298 K is 150 K bar. If the gas exerts a partial pressure of 2 bar, the number of millimoles of the gas dissolved in 1 L of water is (a) 0.55 (b) 0.87 (c) 0.37 (d) 0.66

The properties of the solutions which depend only on the number of solute particles but not on the nature of the solute are called colligative properties. Relative lowering in vapour pressure is also an example of colligative properties. For an experiment, sugar solution is prepared for which lowering in vapour pressure was found to be 0.061 mm of Hg.(vapour pressure of water at \(20^\circ\)C is 17.5 mm of Hg). Answer the following MCQs by choosing the most appropriate options: (i) Relative lowering of vapour pressure for the given solution is- (a) 0.00348 (b) 0.061 (c) 0.122 (d) 1.75 (ii) The vapour pressure (mm of Hg) of Solution will be (a) 17.5 (b) 0.61 (c) 17.439 (d) 0.00348 (iii) Mole fraction of sugar in the solution is (a) 0.00348 (b) 0.9965 (c) 0.061 (d) 1.75 (iv) If weight of sugar taken is 5 g in 108 g of water then molar mass of sugar will be (a) 358 (b) 120 (c) 240 (d) 400 (v) The vapour pressure (mm of Hg) of water at 293 K when 25 g of glucose is dissolved in 450 g of water is (a) 17.2 (b) 17.4 (c) 17.120 (d) 17.02

Read the passage given below and answer the following questions: All real structures are three-dimensional structures. They can be obtained by stacking two dimensional layers one above the other while placing the second square close packed layer above the first we follow the same rule that was followed when one row was placed adjacent to the other. The second layer is placed over the first layer such that the spheres of the upper layer are exactly above there of the first layer. In his arrangement spheres of both the layers are perfectly aligned horizontally as well as vertically. A metallic element crystallise into a lattice having a ABC ABC pattern and packing of spheres leaves out voids in the lattice. 1) What type of structure is formed by this arrangement? (A) ccp (B) hcp (C) ccp/fcc (D) none of the above 2) Name the non-stoichiometric point defect responsible for colour in alkali metal halides. (A) Frenkel defect (B) Interstitial defect (C) Schottky defect (D) F-centres 3) What is the total volume of atoms in a face centred cubic unit cell of a metal? (r is atomic radius). (A) 16/3 \(πr^3\) (B) \(πr^3\) (C) 24/3 \(πr^3\) (D) 12/3 \(πr^3\) 4) Which of the following statements not true for the amorphous and crystalline solids? (A) Amorphous solids are isotropic and crystalline solids are anisotropic. (B) Amorphous solids are short range order and crystalline solids are long range order. (C) Amorphous solids melt at characteristic temperature while crystalline solids melt over a range of temperature. (D) Amorphous solids have irregular shape and crystalline solids have a geometrical shape.

Boiling point or freezing point of liquid solution would be affected by the dissolved solids in the liquid phase. A soluble solid in solution has the effect of raising its boiling point and depressing its freezing point. The addition of non-volatile substances to a solvent decreases the vapor pressure and the added solute particles affect the formation of pure solvent crystals. According to many researches the decrease in freezing point directly correlated to the concentration of solutes dissolved in the solvent. This phenomenon is expressed as freezing point depression and it is useful for several applications such as freeze concentration of liquid food and to find the molar mass of an unknown solute in the solution. Freeze concentration is a high quality liquid food concentration method where water is removed by forming ice crystals. This is done by cooling the liquid food below the freezing point of the solution. The freezing point depression is referred as a colligative property and it is proportional to the molar concentration of the solution (m), along with vapor pressure lowering, boiling point elevation, and osmotic pressure. These are physical characteristics of solutions that depend only on the identity of the solvent and the concentration of the solute. The characters are not depending on the solute’s identity. Answer the following MCQs by choosing the most appropriate options: (i) When a non volatile solid is added to pure water it will- (a) boil above \(100^\circ\)C and freeze above \(0^\circ\)C. (b) b) boil below \(100^\circ\)C and freeze above \(0^\circ\)C. (c) boil above \(100^\circ\)C and freeze below \(0^\circ\)C. (d) boil below \(100^\circ\)C and freeze below \(0^\circ\)C. (ii) Colligative properties are (a) dependent only on the concentration of the solute and independent of the solvent’s and solute’s identity. (b) dependent only on the identity of the solute and the concentration of the solute and independent of the solvent’s identity. (c) dependent on the identity of the solvent and solute and thus on the concentration of the solute. (d) dependent only on the identity of the solvent and the concentration of the solute and independent of the solute’s identity. (iii) Assume three samples of juices A, B and C have glucose as the only sugar present in them. The concentration of sample A, B and C are 0.1 M, 0.5 M and 0.2 M respectively. Freezing point will be highest for the fruit juice (a) A (b) B (c) C (d) all have same freezing point (iv) Identify which of the following is a colligative property? (a) Freezing point (b) Boiling point (c) Osmotic pressure (d) All of the above