Physical Chemistry Questions

ir this yellow highlighted line is really confuse me and I c n t understand that line ease you on pen paper tell me in simple way Fraction of molecules 10 Energy of activation This area shows fraction of molecules reacting at t This area shows fraction of additional molecules which react at 10 Kinetic energy Fig 4 9 Distribution curve showing temperature dependence of rate of a reaction temperature is raised the maximum of the curve moves to the higher energy value Fig 4 9 and the curve broadens out i e spreads to the right such that there is a greater proportion of molecules with much higher energies The area under the curve must be constant since total probability must be one at all times We can mark the position of E on Maxwell Boltzmann distribution curve Fig 4 9 Increasing the temperature of the substance increases the fraction of molecules which collide with energies greater than E It is clear from the diagram that in the curve at t 10 the area showing the fraction of molecules having energy equal to or greater than activation energy gets doubled leading to doubling the rate of a reaction In the Arrhenius equation 4 18 the factor e Ea RT the fraction of molecules that have kinetic energy greater than E corresponds to Taking natural logarithm of both sides of equation 4 18 E In k In A RT 4 19 The plot of In k vs 1 T gives a straight line according to the equation 4 19 as shown in Fig 4 10

are 17 For a given exothermic reaction K and K the equilibrium constants at temperatures T and T respectively Assuming that heat of reaction is constant in temperature range between T and T AIPMT 2014 it is readily observed that 1 K K p 3 K K 2 K K p 1 K to ainstal 4 K p

A cubic crystalline ionic solid AB is like rock salt stucture in which B ion is present at body centre If all the ions along one axis passing through opposite face centres are removed then which of the following statements is are correct about resulting crystalline solid A Formula of resulting crystalline solid is A B 1 B Minimum distance between B ion in the resulting crystal is equal to 2 of unit cell C Number of nearest B ion of B ion is 8 in the resulting crystal Percentage decrease in density is 25 times of edge length

Draw a PC pH diagram for a diprotic acid with a Ka1 10 5 M K 2 109 and CTA 10 3 M At what pH is the concentration of A 2 is 10x greater than the concentration of hydroxide ion HO At what pH is the concentration of HA is 1 000x greater than the concentration of hydroxide ion HO

SolveLancer Test Which of the following is the type of interaction present when substrate bind to enzyme SolveLancer Test 1 Ionic bonding 2 Hydrogen bonding 3 van der Waals interaction 4 dipole dipole interaction a 1 2 b 1 2 3 c 1 2 3 4 d 2 3 4

Trial 3 Volume of liquid ml 10 9 8 REPORT Trial 4 Mass of graduated cylinder and liquid g SUMMARY 0 01 Saved

There were 35 students in a hostel If the number of students is increased by 7 the expenditure on food increase by Rs 42 per day while the average expenditure of students is reduced by Rs 1 What was the initial expenditure on food per day a Rs 400 c Rs 442 d Rs 420 b Rs 432 e None of these

A sample of hydrogen atoms in ground state absorbs light of x nm If the excited sample emits the radiations of six different photon energies but the detector of these emitted radiations has not detected Ans 0100 ultraviolet radiations then the value of x is Given RH 1 96 x10 m

In a cubic unit cell atoms A are present at all corner B atoms are present at non adjacent face center and also at edge centers which are not common to the faces containing B atoms at the centres C atoms are present at body centre remaining face centers The formula of give solid can be O O AB C3 AB C2 ABC

The mechanism of the reaction A C is given below A B k k B fast C slow By using d B dt reaction is given by r K A 0 the rate law of the above Where k is the rate constant of the overall reaction A C If Kf 2 sec k 0 4 sec and k 0 1 sec the value of 10 k will be in units of sec

If we consider that 1 6 in place of 1 12 mass of carbon atom is taken to be the relative atomic mass unit the mass of one mole of a substance will AIEEE 2005 a be a function of the molecular mass of the substance b remain unchanged c increase two fold d decrease twice

16 For the mA nB elementary reaction products A is present in excess and when the concentration of B is changed from 0 01 to 0 02 the rate of reaction becomes 4 times then the rate law determined experimentally can be Or K A m B n Or K A B 2 O r K A B r K A B

174 For an equilibrium H O s of the following statements is true A The pressure changes do not affect the equilibrium H O 0 which B More of ice melts if pressure on the system is increased C More of liquid freezes if pressure on the system is increased D The pressure changes may increase or decrease the degree of advancement of the reaction depending upon the temperature of the

Moles of solute Molarity 120 60 moles of solute volume L of solution 2 05 mol L 2 mol 2 The mass of potassium dichromate crystals required to oxidise 750 cm of 06 M Mohr s salt solution is molar mass 392 a 0 49 g b 0 45 g c 22 05 g d 2 2 g Exp c Mohr s salt is FeSO NH SO 6H O Only oxidisable part Fe is Fe Fe e x6 00 14H 6e20 7H0 6Fe 0 0 14H Millimoles of Fe 750x0 6 450 Moles of Fe 450 1000 6 mol Fe 1 mol Cro 0450 mol Fe a 5 55x 10 M c 3 33x 10 M Exp a Molality 0 450 6 0 075 x 294 g 22 05 g 3 The molality of a urea solution in which 0 0100 g of urea NH CO is added to 0 3000 dm of water at STP is AIEEE 2011 W Molality Moles of urea 2 mol 0 974 L 300 ml x 6Fe 2Cr 7H O 0 0100 60 x 0 2999 0 450 mol moles of the solute mass of the solvent in kg 0 0100 g 19 mL AIEEE 2011 b 33 3M d 0 555 M 60 g mol Mass of 1000 mL of solution volume x density 0 075 mol Cr O 300 g Mass of solvent 300g 0 0100 g 299 9g 0 2999 kg t 1 dm 1000 mL 555 x 10 mol kg 4 Amount of oxalic acid present in a solution can be determined by its titration with KMnO solution in the presence of H SO The titration gives unsatisfactory result when carried out in the presence a gets oxidised by oxalic b furnishes H ions in addition to those from oxalic acid c reduces permanganate to Mn d oxidises oxalic acid to carbon dioxide and water Exp c Titration of oxalic acid by KMnO in the presence of HCI gives unsatisfactory result because HCI is a better reducing agent than oxalic acid and HCI reduces preferably MnO to Mn 45 In the reaction 2Al s 6HCl aq 2Al aq 6CI aq 3H g AIEEE 2007 a 6L HCl aq is consumed for every 3L H g produced b 33 6 LH g is produced regardless of temperature and pressure for every mole Al that reacts c 67 2 LH g at STP is produced for every mole Al that reacts d 11 2 LH g at STP is produced for every mole HCI aq consumed Exp d 2Al s 6HCl aq 2A aq 6C aq 3H g From the equation it is clear that 6 mol of HCI produces 3 mol of H 3 x 22 4 6 or 1 mole of HCI Lot H 11 2 L of H How many moles of magnesium phosphate Mg PO will contain 0 25 mole of oxygen atoms AIEEE 2006 a 0 02 c 1 25x 102 b 3 125 x 10 d 2 5x 10 Exp b 8 moles of O atom are contained by 1 mole Mg3 PO4 2 Hence 0 25 moles of O atom are contained by x 0 25 mol Mg PO4 3 125 x 10 8 47 If we consider that 1 6 in place of 1 12 mass of carbon atom is taken to be the relative atomic mass unit the mass of one mole of a substance will AIEEE 2005 a be a function of the molecular mass of the substance b remain unchanged c increase two fold d decrease twice Exp b The mass of one mole of a substance will remain unchanged

Consider the elementary parallel reaction as given below B A k G It is given that the half life period of the reactant A is 0 0693 min and at a given instant the concentration of B is 3 times the concentration of C then the value of 10k in min is

A buffer solution cannot be prepared by mixing solution of O Potassium chloride and Potassium hydroxide O Ammonium hydroxide and Ammonium chloride Acetic acid and Sodium acetate vis BULL

6 Which one is a wrong statement 1 Total orbital angular momentum of electron in s orbital is equal to zero 2 An orbital is designated by three quantum numbers while an electron in an atom is designated by four quantum numbers 3 The electronic configuration of N atom is 2s 2p 2p 2p 1 1s y

For the endothermic reaction 3 A g B g C g select the option s by which equilibrium concentration of A g can be decreased Decreasing the temperature O O Decreasing the volume of the container Increasing the volume of the container Adding Bla at equilibrium

P B With reference to the above graph choose the correct option for fixed amount of an ideal gas in going from A to B VA VB T k O Volume firstly decreases TX

Solve lancer test Choose the correct statement Solve lancer Test a Addition of Hydrogen cyanide to carbonyl compound b preferably occurs in both acidic as well as basic medium Carbonyl compounds say ketone on treatment with Grignard reagent produces 2 alcohols c Carbonyl compounds form crystalline addition compounds on treatment with NaHSO3 d None of the above statement is true

A sample containing 1 mol KHC O4 H C O4 is titrated with different reagents Select correct statement s 1 mol of KOH is used 3 2 moles of Ba OH 2 is used 4 5 mol of KMnO4 is used in faintly alkaline medium

3 Using the Gibbs energy change AG 63 3 kJ for the following reaction Ag CO3 s 2Ag aq CO aq the Ksp of Ag CO3 s in water at 25 C is R 8 314 J K 1 mol 1 3 2 x 10 26 2 8 0 x 10 12 3 2 9 10 3 4 7 9 x 10 AIPMT 2014

lat 37 The balanced MnO4 aq SO g Mn aq HSO aq 3 form of the given Texn 1 2MnO4 aq 5SO g 5H aq 2Mn 5HSO aq 2 2MnO4 aq 5SO g 2H O 1 H aq 2Mn aq 5HSO aq 3 5MnO4 aq 2SO g 5H O 1 H aq 2Mn 2 aq 5HSO aq 4 MnO4 aq 5SO g 2H O 1 H aq Mn 2 aq TUT ows 1 FUGO 1 12

V E cell AG Keq of cell reaction 2 Questions 1 For a fuel cell 2H g O g 2H O E cell is 1 23 V the value of AGO and nature of the cell reaction is 1 23 7 kJ mol 1 feasible 2 237 3 kJ mol 1 non feasible 3 23 7 kJ mol 1 non feasible 4 237 3 kJ mol 1 feasible

ing point 6 A solution containing 12 5 g of non electrolyte substance in 185 g of water shows boiling point elevation of 0 80 K Calculate the molar mass of the substance K 0 52 K kg mol a 53 06 g mol 1 b 25 3 g mol c 16 08 g mol 1 et d 43 92 g mol 1

The slope of straight line ploted between log a x and t is 51 log a x equal to 0 03 The rate constant of reaction is 1 6 9 x 10 2 2 6 9 3 0 69 4 6 9 x 10 fuffranian 1 6 9 x 10 2 6 9 3 0 69 4 6 9 x 104

Consider the given diagram A B aq If on dipping A in B SO4 aq the colour of the solution changes from colourless to blue then NCERT Pg 279 A and B respectively are colourlers 1 Ag and Cux 2 Cu and Ag 3 Cu and Au

SolveLancer Test In the following reaction to produce 89 6 L of ammonia at STP how many moles of N and H will be required respectively SolveLancer Test N g 3H g 2NH3 g a 1 3 b 2 6 c 3 9 d 0 5 1 5

For the reaction K A B k 1 78 x 10 min 1 and k 5 8 10 5 min when the initial concentration of A is 0 0174 mola at 0 C The time at which the concentration of B is C X maximum is X The value of in hr is to the 11 nearest integer log 1 78 and log 5 8 are 0 2504 and 0 7624 rospectively

What will be hydrolysis constant of anilinium hydrochloride Pt H 1 atm H 1 M PhNH C1 M 32 H 1 atm Pt if cell potential of the cell is 0 188 volt at 298 K a 1 352 x 10 5 b 4 32 x 10 6 c 8 72 x 10 5 d 7 98 10 4

Name the compound shown below 5 ethyl 4 methyl 2 heptyne O 4 ethyl 5 methyl 2 heptyne 4 methyl 3 ethyl 5 heptyne 5 methyl 4 ethyl 2 heptyne 4 methyl 5 ethyl 2 heptyne 3 ethyl 4 methyl 5 heptyne

5 g of solid adsorbent is dropped in a container of 1 5 L N gas at 1 atm and 300 K The pressure of N is reduced to 20 The mass of nitrogen in g adsorbed per gram of adsorbent is Given R 0 08L atm K mol

175 Arrange the orbitals of H atom in the increasing order of their energy 3px 2s 4dxy 3s 4pz 3py 4s A 2s 3s 3px 3py 4s 4p 4dxy B 2s 3s 3px 3py 4s 4p 4dxy C 2s 3s 3px 3py 4s 4pz 4dxy 20 An Ad r

mA nB products A is present in excess and when the concentration of is changed from 0 01 to 0 02 the rate of reaction becomes 4 times then the rate law determined experimentally can be O r k A m B n Or k A B n 2 O r K A B Qr K AUB

SolveLancer Test Write the complete combustion reaction of butane What is the sum of whole number stochiometric coefficients involved in the balanced chemical equation SolveLancer Test a 30 b 31 c 32 d 33

For a reaction of the type A B C going to product the following observations are made Doubling theconcentration of A doubles the rate doubling concentration of B has no effect on the rate and tripling the concentration of C increases the rate by a Select one O A rate k A 2 B C 2 O B rate k A C 2 O C rate k A 2 B C O D rate k A B C

Which of the following is a buffer solution 1 500 ml of 0 1 N CH COOH 500 mL of 0 1 N NaOH 2 500 ml of 0 1 N CH COOH 500 mL of 0 1 N HCI 3 500 ml of 0 1 N CH COOH 500 mL of 0 2 N NaOH 4 500 ml of 0 2 N CH3COOH 500 ml of 0 1 N NaOH Answe

7 A reaction takes place in three steps with individual rate constant and activation energy Activation energy Rate constant E 180 kJ mol a1 Step 1 Step 2 Step 3 k 1 140 kJ mol k k overall rate constant k E 80 kJ mol 22 Ea 50 kJ mol 23 2 3 k k k 2 150 kJ mol overall activation energy of the reaction will be 3 130 kJ mol 4 120 kJ mol

67 An aqueous solution contains 0 10 M H S and 0 20 M HCl If the equilibrium constants for the formation of HS from H S is 1 0 x 10 7 and that of S2 from HS ions is 1 2 x 10 13 then the concentration of S ions in aqueous solution is A 5 x 10 19 C 3 x 10 20 B 5 x 10 8 D 6 x 10 21

Heat of combustion of ethyl alcohol carried out in a bomb calorimeter at 300K is 1350kJ mole Enthalpy of combustion of ethyl alcohol at the same temperature would be A 1347 5 kJ B 1350 kJ C 1349 6 kJ D 1352 5 kJ

In a reversible compression process 1 mol of ideal gas in a piston cylinder device 3 undergoes a pressure change from 1 bar to pressure P and temperature increases from 400 K to 900 K The compression path is described by PV 3 constant Calculate the final pressure and heat transferred Given Heat capacity of gas Cp 30 84 J mol K

The position vector of a particle is r a cos oot i a sin oot j The velocity vector of the particle is a Parallel to position vector b Perpendicular to position vector c Directed towards the origin d Directed away from the origin

17 For a reaction A Product the graph of half life versus initial concentration of reactant is given as tiz hr 4 2 2 2 2 The order of reaction is 1 O 2 1 A

respectively 1 40 60 2 78 22 3 66 6 33 3 1 40 8 2 78 8 3 66 68

A solution contain equal moles of CH COOH and CH3COONa The pH will ch significantly if 1 small amount of CH3 COONa is added without changing volume pot pla 2 small amount of CH3COOH is added without changing volume 3 the solution is diluted 4 moles of CH3COOH equal to moles of CH3COONa are added

1714 171 Which of the following conditions regarding a chemical process ensures its spontaneity at all temperature A AH 0 AG 0 C AH 0 AS 0 B AH 0 AS 0 D AH 0 AS 17

Consider the following unbalanced redox reaction Hg 2 NO3 H Hg HNO2 H O 1M 1M wwwwwww 1M wwwm 1M www w Concentration of ionic species are given at equilibrium If E cell of the given reaction is 0 09 V calculate the minimum pH required to reach equilibrium

2 If in 0 2 mol CuSO4 aq solution 0 5 mol KI is added then freezing point of solution assume 100 ionization 1 Will increase 2 Will decrease 3 Remain same 4 Will decrease and becomes half

pH of a saturated solution of Ba OH is 12 The value of solubility product Ksp of Ba OH is AIPMT Prelims 2012 2 5 0 10 6 4 5 0 10 7 1 4 0x10 6 10 7

The electronic configuration of Cu II is 3d whereas that of Cu I is 3d 0 Which of the following is correct Cu ll is more stable CORRECT ANSWER Cu l and Cu II are equally stable N Cu ll is less stable INCORRECT Stability of Cu I and Cu II depends on nature of copper salts