Physical Chemistry Questions

A gas is allowed to expand in a well insulated container against a constant external pressure of 2 5 atm from an initial volume of 2 50 L to a final volume of 4 50 L The change in internal energy AU of the gas in joules will be 1 500 J 3 505 J 2 505 J 4 1136 25 J

What is the wavelength of light emitted when the electron in a hydrogen atom undergoes a transition from energy level n 4 to n 2 486 nm 91 1 nm 678 nm 289 nm

42 The acid catalysed hydrolysis of an organic compound A at 30 C has a time for half change of 100 min when carried out in a buffer solution at pH 5 and 10 min when carried out at pH 4 Both times o half change are independent of the initial concentration of If the rate constant K is given by Ch d A dt A a 1 b 1 K A H what are the values of a and b B a 2 b 1 C a 0 b 1 D a 1 c 0

A highly concentrated solution of potassium sulphate in water is electrolysed using iner electrodes The products at the cathode and anode are respectively a H 0 b O H c 0 Na d H s o

3 3 An ideal gas expands isothermally from 10 3 m to 10 2 m at 300 K against a constant pressure of 105 N m 2 The work done on the gas is a 270 kJ 900 kJ I for b 900 J d 900 kJ Odisha NEET 2019

Sodium and potassium react with water much more vigorously than lithium because a Sodium and potassium have high values of hydration energy as compared to that of lithium b Sodium and potassium have higher melting point than that of lithium c Sodium and potassium have lower melting point than that of lithium d Sodium and potassium have lower hydration energy than that of lithium hinbest reactivity towards

Answers bracketed with questions 1 1 g of helium gas is confined in a two litre flask under a pressure of 2 05 atm What is its temperature 200 K The density of H 01701

The decomposition of dimethyl ether leads to the formation of CH4 H and CO and the reaction rate is given by Rate k CH OCH 1 2 The rate of reaction is followed by increase in pressure in a closed vessel so the rate can also be expressed in terms of the partial pressure of dimethyl ether i e Rate k PCH 0CH 2 If the pressure is measured in bar and time in minutes then what are the units of rate and rate constants

3 The density of an ideal gas A is 1 43 g L at STP Determine the density of A at 17 C and 700 torr mm 1 24 g L 4 A container has 3 2 g of a certain gas at NTP What would be the mass of the same gas contained in the same vessel at 200 C and 16 atm pressure 29 534 g Hint Mol wt M 3 2 x 22 4 V vol in lit Apply pV W RT M w wt of the gas in g at 473 K and 16 atm 5 Calculate the volume occupied hu C

size 1 3 Decrease B CI Ipcrease Decrease B CI B CI Decrease Increase Decrease Decrease Decrease Decrease C S C S C S Decrease Increase Decrease Decrease Decrease Decrease N P Increase N P Increase N Decrease et to 83 31 1 Decrease 3 B 4 CI Increase B Decrease CI Decrease Increase Decrease CI C S Decrease Decrease Decrease C Decrease Increase Decrease S N P Decrease Decrease Increase N Increase P Decrease N Li Ng Ic Rb Decrease Be mej 4 0 40A 2rty f

6 The correct order of the lattice energies of th following ionic compounds is A NaCl MgBr2 CaO Al2O3 B NaCl CaO Mg Br Al O3 C Al2O3 MgBr2 CaO NaCl D MgBr2 Al2O3 CaO NaCl E Al2O3 CaO MgBr NaCl dical 200

C60 buckyball is cubic closest packed face centered cubic in its crystalline form If you insert potassium atoms into all the tetrahedral and octahedral holes of the C60 structure the formula would become KC60 What is the value of x A 1 B 2 C 3 D 4

An aqueous solution of 0 1 molal concentration of glucose should have freezing point k 1 86 K mol kg 0 186 C 1 86 C 0 186 C 1 86 C

51 Identify the correct statement from below concerning the structure of CH C CH A The molecule is planar B One of the three carbon atoms is in an sp hybridized state C The molecule is non planar with the two CH groups being in planes perpendicular to each other D All the carbon atoms are sp hybridised E The molecule is bent with the C C C angle being 120 degrees

What is the SI unit for heat Select an answer and submit For keyboard navigation use the up down arrow keys to select an answer a Gallons b Grams n d Joules Moles

U14 L3 Kc for the following reaction is 0 15 2SO3 g 2SO2 g O2 g Where SO2 0 76 M 02 0 29 M and SO3 1 9 M Find Q and predict how the reaction will proceed Q 0 05 the reaction will move to the right Q 0 15 the reaction is at equilibrium Q 23 the reaction will move to the left Q 0 044 the reaction will move to the right Q 0 044 the reaction will move to the left

The bond length and bond angles in the molecules of methane ammonia and water are given below C 0 109 nm 109 5 H 2 H H 0 104 5 N 0 101 nm K 107 H A 0 096 nm H H The variation in bond angle is a result of 1 The increasing repulsion between hydro gen atoms as the bond length decreases The number of non bonding electron pairs in the molecula

Group and block for given electronic configuration Xe 4f 5d 6s 54 1 2nd group and s block 2 IIIB group and s block 3 IIIB group and f block 4 None of these Whic C

A dilute aqueous solution of an organic compound soluble in water is formed by dissolving 2 35 g of the compound in water to form 0 250 L of solution The resulting solution has an osmotic pressure of 0 605 atm at 25 C Assuming that the organic compound is a nonelectrolyte what is its molar mass 380 g mol 360 g mol 180 g mol

The rate of hydrolysis of methyl acetate reaction is studied by 1 poin at different time inervals determining the amount of methanol formed determining the amount of methanol consumed determining the amount of acetic acid formed determining the amount of acetic

Use and interpret standard heats of formation a Write the balanced chemical equation that represents the standard heat of formation of HF g at 298 K Be sure to specify states Write fractions with a slash such as 1 2 for one half If a box is not needed leave it blank 1 b The standard enthalpy change for the following reaction is 511 kJ at 298 K 2 BrFy g Br 1 3 F g What is the standard beat of formation of BrF3 g kJ mol

Gradient elution of analytes in HPLC would mean 1 marks O a mobile phase composition is constant during sample analysis time mobile phase flow rate changes with time O b O c mobile phase composition changes during sample analysis d column temperature changes with time

5 1 0 g of magnesium is burnt with 0 56 g O in a closed vessel Which reactant is left in excess and how much At wt Mg 24 0 16 1 Mg 0 16 g 2 02 0 16 g 3 Mg 0 44 g 4 0 0 28 g WOS LOVE LIR

31 Suppose the elements X and Y combine to form two compounds XY and X3Y When 0 1 mole of XY weights 2 10 g and 0 05 mole of X3Y weighs 9g the atomic weights of X and Y are 1 20 30 2 2 30 20 3 40 30 4 60 40

dissolves like When a solid solute is added to the solvent some solute dissol and its concentration increases in solution This process is known dissolution Some solute particles in solution collide with the solid sol particles and get separated out of solution This process is known crystallisation A stage is reached when the two processes occur att same rate Under such conditions number of solute particles go into solution will be equal to the solute particles separating out a a state of dynamic equilibrium is reached Solute Solvent Solution 2 1

164 A compound is formed by cation C and anion A The anions form hexagonal close packed hcp lattice and the cations occupy 75 of octahedral voids The formula of the compound is 3 C A3 4 C A 2 C4A3 hcp A 1 C3A4 64 1 c OV 6x 3 4 75 100 6 1

In a certain reaction Bn is getting converted to B n 4 in solution The rate constant for the reaction is measured by titrating a volume of the solution with a reducing agent which reacts only with Bn and B n 4 In this process it converts Bn to B n 2 and B n 4 to B n 1 At t 0 the volume of reagent consumed is 25mL and at t 10min the volume used is 32mL Calculate the ate constant for conversion of Bn to B n 4

Mg 2e Mg E 2 37V When zinc dust is added to the solution of MgCl2 a ZnCl2 is formed b zinc dissolves in the solution c no reaction takes place d Mg is precipitated with normal hyd

A very hard crystalline solid that melts at very high temperature cannot conduct electricity either in solid state or in molten state What kind of crystalline solid is this What type of constituent particles does this solid consist of What is the nature of forces that holds the particles in this solid

Which of the following equations represent standard heat of formation of CH4 A C diamond 2H2 g CH4 g B C D C graphite 2H g CH4 g C diamond 4H2 g CH4 g C graphite 4H2 g CH4 g

106 The lanthanide compound which is used as a most powerful liquid laser after dissolving in selenium oxychoride is 1 Cerium oxide 2 Neodymium oxide 3 Promethium sulphate 4 Cerium sulphate 107 11

In which of the following reactions standard reaction entropy change AS is positive and standard Gibb s energy change AG decreases sharply with increasing temperature 1 Mg s O g MgO s 1 2 2 C graphite 4 CO g 1 2 no 1 axe lemmistoal 3 C graphite O2 g CO g 2 0 g CO g 1 1 oigo en wolloor to doin O g CO g

Which of the following sets of atomic numbers corresponds to elements of group 16 A 8 16 32 54 B 16 34 54 86 C 8 16 34 52 D 10 16 32 50

Mole fraction of component A in vapour phase is X and mole fraction of component A in liquid mixture is x2 P vapour pressure of pure A Po vapour pressure of pure B then the vapour pressure of liquid mixture is Question Type Single Correct Type 1 2 3 P X2 X PX1 X2 PBX1 X2

The pH of mixture obtained by mixing Vml each of 0 1M salicylic acid and 0 1M NaOH is x The Ka 1 and Ka of salicylic acid are 10 4 and 10 7 respectively at T Kelvin The value of x is 5 5 The value of x is 1 5 The pH of above mixture is independent of concentration of salt formed If V mL 0 1 M NaOH is further added to the above mixture complete neutralisation of salicylic acid takes place

3 A first order reaction at 300 K temperature takes about 75 completion of 20 Takes minutes When the same reaction was done at 300x then what percent of the reaction will be completed in 40 minutes R 8 K mole In 2 0 7 1 12 5 2 93 75 06 25 4 87 5

87 Which of the following overlaps is incorrect assuming z 87 axis to be the internuclear axis 1 2 py 2 py 2 py Py T 2 2 P 2 P o 2p 3 2 Px 2 px 2 Px 4 1 s 2 py m 1 s 2 py 1 a b 2 b d 3 only d A N fth

52 The value of potential energy 2 x kinetic energy of an 52 flat electron in any orbit is equal to m3 1 zero FLY 8 22 2 1 8 27 3 2 x total energy 4 total energy For which of the follo 32 27 E 8 R 2 1 3 2 x f 4 fra 3 2x PE q P E 2 2

For a particular reaction in a galvanic voltaic cell AS is negative Which of the following statements is true Os will increase with an increase in temperature Os will decrease with an increase in temperature Os will not change when the temperature increases AG 0 for all temperatures None of these statements is true

55 The speed of the electron in the 2nd orbit of the hydrogen 55 Eater than atom c is the velocity of light 1 c 1 37 2 274 3 c 13 7 4 c 137 1 c 1 37 c 274 3 c 13 7 4 c 137 e x B 137 C

Which of the following aq solution will have highest boiling point 0 1 m Sucrose 0 1 m Glucose 0 1 m NaCl 0 1 m CaCl

A schematic representation of enthalpy changes for the C graphite O g CO g reaction is given below The missing value is A B Cgraphite O g T 393 5 KJ CO g 10 5 kJ 11 5 kJ CO g 1 2O g 283 0kJ

26 What is the mass of the precipitate formed when 50 mL of 16 9 solution of AgNO3 is mixed with 50 mL of 5 8 NaCl solution Ag 107 8 N 14 O 16 Na 23 Cl 35 5 3 28 g 1 7 g 2 14 g 4 3 5 g 21 CHEMISTRY NURTUR

The q value and work done in isothermal reversible expansion of one mole of an ideal gas from initial pressure of 1 bar to final pressure of 0 1 bar at constant temperature 273 K are 5 22 kJ 5 22 kJ 5 22 kJ 5 22 kj

2NOBr g certain temp and a total pressure of 0 30 atm Kp for the reaction 2NO g Br g 2NOBr g 2NO g Br g If nitrosyl bromide NOBr is 40 dissociated at

80 g H and 80 g O are taken in a container and allowed to react to form liquid water Y kJ of heat is evolved in the process The enthalpy of formation of water is A B 2 5 Y kJ mol 1 40 Y kJ mol 1 Y II mol Correct Answer

Man standing at the river bank observe swimer is moving with 10 m s at an angle of 60 with river flow direction If width of river is 40 3 then time to cross the river A B 4 s 8 s Correct Answer

The increase in the rate of a reaction with increase in temperature is mainly due to B the increase in collision frequency b the decrease in activation energy c the increase in number of activated molecules d the increase in pre exponential factor h

View In English What is the concentration of Ba CN 2 in the aqueous solution of the mixture of Ba CN 2 and 0 1 M HCN having pH 5 Given pkb for CN at 25 C is E 1 3 4 Correct Answer 4 Four Answer 1 10 2 M 102 M 2x 10 2 M 5x10 3 M

3 1 42 gram mixture of CaCO3 and MgCO3 is dissolved g L in 160 mL of N 4 HCl and the volume of solution is made 250 mL by adding water 10 mL of this solution requires 12 mL of N 30 NaOH for complete neutralisation Calculate the percentage of each component in the original mixture Ans CaCO 70