Physical Chemistry Questions

10 If 1 mol of an ideal gas at constant temperature changes its pressure from 5 atm to 2 atm and volume from 4 L to 10 L then enthalpy change wi be NCERT Pg 167 1 20 L atm 3 Zero 2 120 L atm 4 100 tm

1 Following simultaneous equilibrium takes place in 1 L container 2P g P g P g Q g R s At equilibrium degree of association of P is 0 5 and degree of decomposition of P2 is also 0 5 The vapour density of P and equilibrium mixture are D and d respectively The value of 12 MQ d M and M are molar mass of O and Pl 1 is Given

B D A C In above diagram A has five valence electrons and B C and D have six valence electrons each According to the L D S A has x formal charge B has y and C has z formal cha follows Lewis octet theory Give the answer of following question if A B C D belongs to p block

How can one experimentally determine how many solvent accessible thiol groups there are per molecule of BSA Bovine Serum Albumin from a BSA sample of unknown concentration What would be the experimental design detailed with related calculations Ellman s reagent and related equipment spectrophotometer buffers etc are at your disposal Thanks in advance please let me know if any more information is needed and I will be sure to reply

In colloids particles showing zigzag mo vements are stablized by repulsion due to similar charged particle and do not p recipitate But in case of true solutions the is no electrolyte but still the particle s are not precipitated How

Which of the following statement is not true 1 K Cr O solution in acidic medium is orange 2 K Cr O solution becomes yellow on increasing the pH beyond 7 3 On passing H S through acidified K Cr O solution a milky colour is observed 0 4 The bond angle of Cr O Cr 0 Cr O in

If AB is incident wavefront Then refracted wavefront just after transmission is A B A B B A A Biconvex lens

The Windscale fire is an accident that happened in October 1957 in the U K and has a level 5 severity from the INES scale The accident released radioactive fallout from iodine 131 polonium 210 and possibly strontium 90 What amount of each of the given radioisotopes would have registered a radioactivity of 25 000 Ci Isotope 210Po HA Sr 38 Atomic Mass u 130 9061246 209 9828737 89 907738 Half Life 8 02070 days 138 376 days 28 90 years

26 The vapour pressure of two pure liquids P and Q that form an ideal solution a 100 torr and 400 torr respectively at a temperature T This liquid solution of Par Q is composed of 1 mole of P and 1 mole of Q What will be the pressure when mole of mixture has been vapourised A 200 torr B 300 torr D 700 torr Q No 26 C 500 torr

At 200 C PC1 dissociates as follows PCI g Cl g PC1 g 21 x It was found that the vapours of equilibriu mixture are 62 times as heavy as hydrogen Th degree of dissociation of PC1 at 200 C nearly 1 10 2 42 62 1 6 62

9 For the conversion of water to steam at 110 C and 1 atm determine the sign 0 or for the change in Gibbs free energy the change in enthalpy and the change in entropy Please explain fully

3 60 amu 4 55 amu 45 10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded Volume of gaseous product after reaction 1 1 22 4 L X 2 2 22 4 L 3 3 22 4 L 4 4 22 4 L 46 What is the OH in the final solution prepared by

Copper is a transition metal that forms different coloured complexes A complex Cu H O 5 aq changes colour when excess Cl aq is added Explain the cause of this colour change using section 3 and 15 from the data booklet

Crystal solid consist of X and Y atoms X atom shows ccp structure and Y atom occupied 50 of tetrahedral voids If all corner atoms are removed from the crystal solid then simplest molecular formula of the crystal will be PX4Y3 O X3 Y4 O X2Y3 O Y Yn

A polyhydric alcohol X whenever treated with excess of propanoyl chloride then organic compound Y is obtained if difference in molecular mass of X Y is 280 then no of OH groups in X are The alcohol among following which show dehydration reaction faster than 2 methyl propan 2 ol OH

Two 22 4 litre containers A and B contains 8 g of O and 8 g of SO respect and 1 atm pressure then a Number of molecules in A and B are same 25 I b Number of molecules in B is more than that in A c The ratio between the number of molecules in A to number of molecules in BRG 2 1 27 d Number of molecules in B is three times greater than the number of molecule in A 1 pisegater the

21 Arrange the following polymers in increasing order of their intermolecular force Nylon 6 6 Bakelite Buna S Polythene A G R A A R G U C U G A R Q No 21 OA OB OC OD B R A G U D A R U G

A state of equilibrium is reached when 1 The rate of forward reaction is greater than the rate of the reverse reaction 2 The concentration of the products and reactants are equal 3 More product is present than reactant 4 The concentration of the products and reactants have reached constant value

Sulphide ion reacts with solid sulphur S aq S s S S S2 2 aq 2S s S aq K 130 The equilibrium constant for the formation of S 2 aq from S 2 aq and sulphur is 1 10 2 13 3 130 4 1300 aq aq K 10

3 PCI g PC1 g Cl g 4 14 Heat of combustion of CH4 C H4 and C H are 890 1411 and 1560 kJ mol respectively Which has the lowe calorific fuel value in kJ g 1 CH 3 C H Not sign only magnitud wise 2 C H4 4 All of these 13 7 94 11 2 and 12 4 kcal respectively w

b Use the following phase diagram to answer the following questions L A L A B 50 Wt b D i Determine the degree of freedom at point e ii Determine the degree of freedom at point A L iii Determine the degree of freedom at point B L iv Determine the degree of freedom at point A B 4 B L 100 To Ty

The volume of N gas calculated at S T P is required to cover a sample of silica gel with a monomolecular layer is 610 cc for 5 gram of the gel Calculate the surface area of the gel if the nitrogen gas has a density of 0 03 gram cc at S T P

27 Which of the following represents correct relation between standard electrode po tential and equilibrium constant and choose the correct options from the following codes given below nFE I log K 2 303 RT III log K 0 4342 codes A I II and III are correct C I II and IV are correct Q No 27 nFEo RT nFE II Ke RT IV logK 0 4342 FE RT B II and III are correct D I and III are correct

Q 35 36 Hybridisation is the measure to express the molecular shapes reson ably Hybridisation although theoretical but it is highly correlated with molecular shapes or inter orbital angles If there is any variation in geometry on the basis of VSEPR theory the apparent variation in hybridisation can be observed and the following characteristic relationship is the easiest way to interpret that variation Any hybrid orbital made by s and p orbitals is characterised by the following rela tionship 1 or fp and i i 1 for sp i 3 and sp i 2 for an orbital f fp 1 while all the sp hybrids of given atom must satisfy the condition Ef 1 00 d and the inter orbital angle between two equivalent same f and same fp hybrid orbitals is given by cos 8 fp 35 In BFCIBr molecule which of the following bond have minimum 1 character provided to the central atom A B Cl B B F C B Br D Cannot be predicted

At 17 C the osmotic pressure of sugar solution is 580 torr The solution is diluted and the temperature is raised to 57 C The osmotic pressure is found to be 165 torr The extent of dilution is Only One Correct Answer A 2 times B C D 4 times 6 times A times 0 Marked for Re o Answered and 7 Completed 16 21 CHEMISTR 26 17 22 27

Chose the incorrect statement The constituents of a compound cannot be O separated into simpler substances by physical methods O The properties of a compound are same as its constituent elements An element is consisting of only one type of O particles and these particles may be atoms molecules Atoms of different elements are different in nature

The most probable molecular energy kT at 27 C is kT 2 52x10 2eV to What fraction of the potassium fluoride ion pairs have enough kinetic energy dissociate in the gas phase What fraction of the potassium fluoride ion pairs have enough kinetic energy to dissociate in the aqueous solution

An acidic buffer is obtained on mixing 100 ml of 0 1 M CH3COOH and 100 ml of 0 1 M NaOH 100 ml of 0 2 M H3PO4 and 100 ml of 0 1 M NaOH 200 ml of 0 1 M HCI and 200 ml of 0 1 M Na3PO4 100 ml of 0 1 M HCI and 100 ml of 0 1 M NaOH

RS 4 00 Negative Mark s 1 0 The radius of CI ion is 38 larger than that of the F ion but the radius of the Brion is only 6 5 larger than that of the CI ion The relatively small difference in size between CI and Brion is due to the fact that the Br ion contains ten 3 d electrons which fail to shield the nuclear charge effectively o the Br ion contains ten 3 d electrons which shield the nuclear charge effectively o the Br ion contains six 4p electrons which shield the nuclear charge effectively O the Brion contain ten 3 d electrons and six 3 p electrons together they shield the nuclear charge effectively

CH CH CH A CH CH CH Br B CH CHBr CH CCH CHBr CH Br DBACH CH CH ii HBr peroxide iv Br CCl4 b C d A 0 0 iv mm B 0 0 iv C 1 i iv 1 D mm iv List 11 1 HBr i NBS

Phenol associates in benzene to a certain extent to form dimer A solution con taining 2 0 x 10 2 kg of phenol in 1 0 kg of benzene has its freezing point decreased by 0 69 K The degree of association of phenol is K for benzene 5 12 K kg mol

Express the relation among the cell constant the resistance of the solution in the cell and the conductivity of the solution How is the conductivity of a solution related to its molar conductivity Calculate the degree of dissociation and molar conductivity of ethanoic acid if conductivity of 4 89 X 10 4 M ethanoic acid is 6 78 X 10 5 S cm 1 Given H 429 5 S cm mol and HCOO 49 5 S cm 4

The oxidation of o dianisidine o DIA is electrochemically reversible and involves the transfer of two electrons Linear swee voltammetry was performed on a 2 M H SO solution containing 2 66 mM of o DIA using a carbon paste electrode with an of 3 36 mm At a scan rate of 500 0 mV s the peak current was 8 80 A Determine the diffusion coefficient D for o DIA D 035 10 6 Incorrect Determine the peak current if the scan rate is reduced to 225 0 mV s

A B ve N2 g 3H2 g 2NH3 g AH N2 g O2 g 2NO g AH ve C A g B g 2C g D g AH ve D PC15 g PCl3 g Cl2 g AH ve m P S List 11 K increases with increase in temperature K decreases with increase in temperature Pressure has no effect Moles of product increase due to addition of inert gas at constant pressure

In the following reaction NO 2e NO Select the incorrect statement Hybridisation of central atom gets changed Formal charge on central atom gets changed O Oxidation state of central atom gets changed O Maximum number of atoms lying in one plane

A closed vessel contains a mixture of two diatomic gases A and B Molar mass of A is 16 times that of B and mass of gas A contained in the vessel is 2 times that of B Average kinetic energy per molecule of gas A is equal to that of gas B Root mean square value of translational velocity of gas B is four times that of A Pressure exerted by gas B is eight times of that exerted by gas A Number of molecules of gas B in the cylinder is eight times that of gas A

In Haber process 30 L of dihydrogen and 30L of linitrogen were taken for reaction which yielded only 50 of the expected product What will be the composition of the gaseous mixture under the aforesaid conditions in the end 1 20L NH3 25LN and 20LH 2 10L NH3 25L N and 15LH 3 20LNH3 10LN and 30LH 4 20L NH 25LN and 15LH

4 The dissociation constants for acetic acid and pyridine are 1 8 x 10 5 and 1 5 x 10 9 respectively Calculate the degree of hydrolysis of pyridinium acetate in its 0 1 M solution What will be the effect on degree of hydrolysis when 1 litre of the above solution is mixed with 1 litre of water

2SO 0 2S03 Observed mole fraction for a certain equilibrium mixture at 1000 K and 1767 torr are Xso 0 310 Xo 0 250 and Xso 0 440 a Find Kg and AG at 10 K assuming ideal gases b Find Kp at 100 K c Find the Kg at 1000 K

Which of the following statements best describes the effect of increased carbon dioxide pressure in the blood It reduces the oxygen affinity and the oxygen carrying capacity It reduces oxygen affinity but does not affect the oxygen carrying capacity It affects oxygen affinity and oxygen carrying sulfur capacity

9 A narrow spectrum antibiotic is active against a either gram positive or gram negative bacteria b gram negative bacteria only c single organism or one disease d both gram positive and gram negative bacteria

Calcium lactate is a salt of a weak organic acid and represented as Ca Lac A saturated solution of Ca Lac contains 0 13 mol of this salt in 0 50 litre solution The pOH of this solution is 5 60 Assuming a complete dissociation of the salt calculate K of lactic acid

7 Which of the following statements are correct about CO3 I The hybridisation of central atom is sp II Its resonance structures have one C O single bond and two C O double bonds III The average formal charge on each oxygen atom is 0 67 units IV All C O bond lengths are equal a I and II only c III and IV only b I and III only d II and IV only

0 0 2 Parcul Statement 1 Curve 1 represents the less stable state of the system for H ion Statement 2 Curve 2 represents the most stable state of the system for H ion d Who postulated Valence shell electron pair repulsion theory Explain with examples why in sp hybrid compounds the bond length between Carbon Carbon atom is less than bond length between Carbon Carbon atoms in sp hybrid compounds 2 e Hybridization is an energy requiring process yet it occurs why Explain geometry of the following compounds 131 NH4 PC16 Cu NH3 4 POCI3 ICL BH Q 3 a Explain molecular orbital theory How is it superior to Valence bond theory in explaining the properties of compounds going through examples Workout bond order and magnetic properties of these molecules of Li and B 131 presence of lone pair affect the h Explain Gillespie and Nyholm theory with examples

A small block with a mass of 150 gm can slide freely along the smooth inner surface of a semicircular wire with a radius of 8 cm that rotates about a vertical axis at a uniform rate of 2 revolutions per second as shown in the figure Find the value of for which the block will remain stationary with respect to the rotating wire take g 10 m s 8cm

A substance will be deliquescent if its vapour pressure 1 Is equal to the atmospheric pressure 2 Is equal to that of water vapour in air 3 Is less than that of water vapour in air 4 Is greater than that of water vapour in air

7 02 g of benzene containing 0 122 g of benzoic acid freezes at 0 512 C below the freezing point of pure benzene benzoic acid exists as a dimer during this van t Hoff factor is found to be x x 10 1 and degree of association y Kf for benezene is 5 12 K molal The value of x is

15 Consider a fuel cell supplied with 1 mole of H gas and 10 moles of O gas If fuel cell is operated at 96 5 mA current how long will it deliver power Assume 1 F 96500 C mole of electrons a 1 x 106 s b 0 5 106 s c 2 x 106 s e 5 x 106 s S d 4 106 s X

In a cubic crystal A atoms are on all the corners and centre of cube 2 B atoms are present on each body diagonal and C atoms are present on all the face centre Find the formula of compound if all the atoms along one of the 3 fold axis of symmetry are removed

11 A gas balloon having a volume of 10 0 L at 25 C and 1 atm pressure rises to an altitude where the temperature is 10 C and pressure 500 mm of Hg What is the volume of balloon at this altitude above the 100