Physical Chemistry Questions

Which of the following statement s is are correct for a decay a when there is imblanace of number of neutrons and protons for stability a B particle is emitt b when the number of protons is more than that required for stability decay occurs c in a B deay a proton becomes a neutron at the expense of the binding energy of the parent nucleus releasing a positron and neutrino d when a nucleus undergoes B decay the total nucleon number remains constant

At 25 C the dissociation constant of a base BO is 1 0 10 12 The concentration of hydroxyl ions in 0 01M aqueous solution of the base would be AIPMT Prelims 2005 1 2 0 10 mol L 1 2 1 0 10 5 mol L 1 1 0 x 10 6 mol L 4 1 0 10 7 mol L

Given for H atom 1 1 9 3 a R r where 3 2 2Zr nao Orbital is 3s 4xr R r 6 60 0 e 0 2 Select the correct statement s for the given orbital a 0 53A Graph for the given orbital is n r Distance between radial nodes is equal to ao

1 mol of monoatomic ideal gas is compressed point A P 8 L 75 K to B P2 1 L T K in reversible adiabatic process If gas is expanded irreversibly and adiabatically from B to C P3 8 L and T K against the constant external pressure of 1atm Select the correct statement s Take 1atm L 101 3 J and R 8 31 J mol K 1 T3 T 75 K 2 T T 75 K 3 Magnitude of work done in A to B is more than that of B to C 4 Magnitude of work done in A to B is less than that of B to C

24 550 kJ cycle 1 work is done by 1 mol of an ideal gas in a cyclic process The amount of heat absorbed b the system in one cycle is 1 550 kJ 3 1100 kJ 2 550 kJ 4 Zero

4 Following compound represents close packed unit cell of a compound of Titanium IV Strontium II and oxide ions Select correct statements A A layer of lattice can be represented as B There can be 12 equidistance divalent cations to every divalent cation C There can be 6 equidistance tetra valent cations to every tetravalent cati D Oxide ion is surrounded by 6 first nearest cations

Adsorption of nitrogen on charcoal obeys Freundlich isotherm Graph between log X m and log P is a straight line at an angle 45 with intercept on y axis 0 301 At what pressure in atm 0 4 g of nitrogen is adsorbed per g of the charcoal

Which of the following statements are correct 1 The increasing order of osmotic pressure of 0 1 M aqueous solution containing different electrolyte is as follows 0 1 M Glucose 0 1 M NaCl 0 1 MgCl 2 Density of a solution is independent of temperature 3 Camphor has comparatively larger value of Kf as compared to other common solvents 4 Limiting value of van t Hoff factor of K4Fe CN 6 is 11 a Only 1 and 2 c Only 1 2 and 4 b Only 1 and 3 d All of these

The values of Kp and Kp for the reactions X Y Z a 2008 and A2B b are in the ratio of 9 1 If degree of dissociation of X and A be equal then total pressure at equilibrium for a and b are in the ratio a 3 1 b 1 9 c 36 1 d 1 1

of attraction between its particles The latent heat which we supply is used up in overcoming the forces of attraction between the particles of a substance during the change of state The latent heat does not increase the kinetic energy of the particles of the substance And since there is no increase in the kinetic energy of the particles the temperature of a substance does not rise during the change of state

The vapour density of PCl5 is 104 25 but when heated to 230 C its vapour density is reduced to 62 The percentage of dissociation of PC15 at this temperature will be Question Type Single Correct Type 1 2 6 8 68

When 40 cc of slightly moist hydrogen chloride gas is mixed with 20 cc of ammonia gas the final volume of gas left at the same temperatura and pressure will be NH g HCl g 1 20 cc 3 60 cc NH CI s 2 40 cc 4 100 cc

O 2e i in exp io nF RT R kb n exp cnF RT n Use equation above to plot a tafel cathodic curve for n 0 15 volts calculate for the current value for 0 1 0 25 0 45 and 0 6 Then plot log i vs overpotential

Consider the following reversible reaction A g B g AB g The activation energy of the backward reaction exceeds that of the forward reaction by 2RT in J mol If the pre exponential factor of the forward reaction is 4 times that of the reverse reaction the absolute value of AG in J mol for the reaction at 300 K is Given n 2 0 7 RT 2500 J mol at 300 K and G is the Gibbs energy 8500

1 Calculate the uncertanity in position assuming that the uncertainity in determining the momentum is 0 1 for an electron moving in an atom with a velocity of 2 2x10 ms 2 Expand A C and state under what condition A C A C 4 2

A binary feed consisting of 25 mol liquid and 75 mol vapor is separated in a staged distillation column The mole fraction of the more volatile component in the distillate product is 0 95 The molar flow rate of distillate is 50 of the feed flow rate and McCabe Thiele method can be used to analyze the column The q line intersects the operating line of the enriching section at 0 35 0 5 on the x y diagram Calculate the slope of the stripping section operating line S na

What possibly can be the ratio of the de Broglie wavelengths for two electrons each having zero initial energy and accelerated through 50 volts and 200 volts A 3 10 C 1 2 B 10 3 D 2 1

The amino acid serine NH CH CH OH COOH has the following pk values pka1 2 19 pka1 9 21 What is are the major species at pH 2 19 Note in this context major species refers only to the species present in the highest concentration NH3CH CH OH COOH and NH CH CH OH COOH O NH3CH CH OH COOH only O NH CH CH OH COOH only O NH3CH CH OH COOH and NH3CH CH OH COO

ropane C3H8 can be burned to produce heat for homes The products of the reaction are CC nd H O For complete combustion to occur the ratio of the amounts of propane to oxygen mu e adjusted correctly Use the balanced equation C3H8 502 3CO2 4H O to answer the following questions 11 points i How many moles of CO are produced from 5 moles O 1 point

8 The radiation of low frequency will be emitted in which transition of hydrogen atom 1 n 1 to n 4 2 n 2 to n 5 3 n 3 to n 1 4n 5 to n 2 ENGVMODULE 112 ATOMIC STRUCTURE A 10 ATOMIC STRUCTUREV

ane C3H8 can be burned to produce heat for homes The of the reaction are nd H O For complete combustion to occur the ratio of the amounts of propane to oxygen m e adjusted correctly Use the balanced equation C3H8 50 3CO2 4H O to answer the following questions 11 points i How many moles of CO are produced from 5 moles O 1 point ii How many grams of CO are produced from 5 moles O 2 points

1 In addition to performing the reaction N N 2 NH3 nitrogenase is also capable of catalyzing the following reactions Propose a catalytic cycle mechanism starting from intermediate E4in the previous pages for this reaction N N N N2 NH3

he half life period of a gaseous substance undergoing thermal decomposition was measured for various nitial pressure P with the following results mm 6300 5250 1 2 min 136 112 5 Calculate the order of the reaction

A product follows the mechanism as A A A A A A A A Akproduct Choose the correct statements The reaction is 2nd order at low concentration of A vori The reaction is 1st order at higher concentration of C The reaction is zero order D The reaction is 1st order at low concentration of A

A piston cylinder assembly contains water that undergoes a series of processes Process 1 2 Constant volume heating from p1 5bar and T1 160 to P2 10bar Process 2 3 Constant pressure cooling to saturated vapor Process 3 4 Constant volume cooling to T4 160 C Process 4 5 Constant temperature expansion with Q 815 8 kl Sketch the processes on Pt Pv and Tv plots Lable the axes PRESSURE TEMPERATURE and SPECIFIC VOLUME values use clos to make clear the states numbers and process directions

Which of the following is incorrect regarding batteries 1 Primary batteries cannot be recharged and reused again 2 Lead storage battery is an example of secondary battery 3 In a H O2 fuel cell water is electrolysed to give H and O 4 In a Ni Cd battery the specific gravity of the alkaline electrolyte remains same

a ZnS type Sphalerite structure assuming ions forming the lattice all atoms lying on only one body diagonal plane are removed Then select the incorrect atement about the resulting cell Electrical neutrality is not maintained due to this operation The unit cell acquires a negative charge Effectively two Zn ions and S ions are removed

35 P 10 atm V 800 ml 3 Fig I Fig II In the above figures a doll is entrapped within a piston and cylinder containing gas Initial and final conditions are shown Figure I and Figure II respectively Th volume of doll is 1 1000 ml 1000 3 ml P 7 atm V 1000 ml 2 4 15000 17 1000 15 ml ml

Haemoglobin has 0 25 by mass of Iron Fe and cytochrome protein has 0 28 by mass of Iron Fe If a molecule of haemoglobin contains 4 atoms of iron and a molecule of cytochrome protein contains 1 atom of iron then the ratio of molecular mass of haemoglobin and cytochrome protein is Atomic mass Fe 56 A 1 12 B 2 24 C 4 48 D 8 96

Separate samples of two gases each containing a pure substance are found to have the same density under the same conditions of temperature and pressure Which statement about these two samples must be correct A They have the same volume B They have the same relative molecular mass C There are equal numbers of moles of gas in the two samples

The Ksp of Ag CrO AgCl AgBr and Agi are respectively 1 1 x 10 12 1 8 x 10 10 5 0 10 13 8 3 x 10 17 Which one of the following salts will precipitate last if AgNO solution is added to the solution containing equal moles of NaCl NaBr Nal and Na CrO AIPMT 2015 1 Ag CrO4 2 Agl 3 AgCl 4 AqBr

One litre of gaseous mixture of CH4 and H2 effuses in 200 seconds while one litre of gas X take 10 minutes to effuse in identical conditions If molar ratio of CH4 H2 in mixture is 1 2 Find molar mass c gas X in g mol 1 units

A B D of the following is incorrect Some times physisorption and chemisorptions occur simultaneously and it is difficult to ascertain the type of adsorption K When Mg OH is precipitated in presence of magneson reagent it gets blue colour due to adsorption on magneson Freundlich adsorption isotherm fails at high pressure In some cases a physical adsorption at low temperature may pass into chemisorptions as the temperature is increased

2 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

P For a given exothermic reaction K and Kare the equilibrium constants at temperatures T and T2 respectively Assuming that heat of reaction is constant in temperature range between T and T2 it is readily observed that 2014 a K Kp T b K Kp P 1 IN IZ

the photon strikes the electron the impact changes its position and velocity both According to the principle of optics the accuracy with which the position of a particle can be ascertained depends on the wavelength of light used i e uncertainty in position is It shows that shorter the wavelength greater is the accuracy in position But a radiation that has a short wavelength is very energetic in nature When a photon of high energy strikes the electron the impact causes a change in the velocity and

25 3 g of sodium carbonate Na CO3 is dissolved in enough water to make 250 mL of solution If sodium carbonate dissociates completely molar concentration of sodium ion Na and carbonate ions CO2 are respectively Molar mass of Na CO3 106 g mol AIPMT Prelims 2010 1 0 955 M and 1 910 M 2 1 910 M and 0 955 M 3 1 90 M and 1 910 M 4 0 477 M and 0 477 M 4

A particle X moving with a certain velocit has a de Broglie wavelength of 1 A I particle Y has a mass of 25 that of X and velocity 75 that of X de Brogli wavelength of Y will be A 3 C 6 88 B 5 33 D 48

t moderate pressure the compressibility factor for a particular gas is given by 2000P Z 1 0 2P T dentify the correct statements A B C D Below 50K at all temperatures gas can be liquefied by applying high pressure Gas shows ideal behavior at 100 K When gas is subjected to Joule Thomson effect above 200K temperature of cylinder increases Gas is easily liquefied between 50K to 100K and above 100K it is not possible to liquify gas by applying high pressure YOU MARK YOU MARK YOU MARK

In the reaction the number of molecules colliding with sufficient energy be unity for a reaction taking place at 500 K Then the activation energy Ea of the reaction is Ea 0 O Ea 1 O Ea 1 O Ea 1

Calculate the temperature of the system once equilibrium has been reached Assume that Cpm for H O 1 is constant at its values for 298 K 75 3 J mol K throughout the temperature range of interest A Hus for ice is 6010 J mol 1 Express the temperature in kelvins to three significant figures VAX

9 The specific conductivity of a saturated solution of silver chloride is 2 x 10 Scm at 25 C What will the solubility of silver chloride at 25 C if molar conductivities at infinite dilution of Ag and CT ions are and 80 Scm mol respectively A 1 428 x 10 M B 2 382 x 10 M D 4 2 x 10 M Ans A C 2 33 x 10 M

What is the meaning of the line It can be extrapolated when concentration approaches zero in va riation of molar conductivity with concentration topic What is the word extrapolated means accor ding to this line What happens to molar conductivity

The dissociation equilibrium of a gas AB can be represented as 2008 2 AB g 2AB g B g The degree of dissociation is x and is small compared to 1 The expression relating the degree of dissociation x with equilibrium constant K and total pressure P is P b 2K P 3 d K P a 2K P c 2K P 1 2

A colourless gas G produced on treating conc H SO4 with common salt is introduced into one end of a glass tube Through the other end another pungent smelling colourless gas G of molecular mass 17 is introduced A white sublimate S is produced inside the tube Which of the following statements is wrong Both the gas G and G are water soluble Sublimate S contains covalent bonds and ionic bonds Sublimate S when treated with caustic soda liberates G Aqueous solution of each G and G gas is acidic in nature

Consider an electrochemical cell A s A aq 2M B2 aq 1 M B s The value of AH for the cell reaction is twice that of AG at 300K If the emf of the cell is zero the AS in JK mol of the cell reaction per mole of B formed at 300 K is Given In 2 0 7 R universal gas constant 8 3 JK mol H S and G are enthalpy entropy and Gibbs energy respectively 41 6

The characteristic of an ore is are A High of metal impurities C Low expenditure needed for the extraction D The elements which can be recovered on large scale from sea water are B Low amounts of easily removable All

A mixture of CO and CO when treated with 1205 give iodine vapour After removal of 12 residual gas was treated with excess of 0 1 N NaOH and the resulting solution required 30 ml of 1N HCI to reach end point using phenolphthalein and further 10 ml using methyl orange as indicator Total volume of NaOH in mL is X The value of is 10 40

er hexacyanidoferrate III 3 If Avogadro Number NA is changed from 6 022 x 1023 mol 1 to 6 022 x 1020 mol 1 then no of atoms present in 11 20 L of a gas y 1 4 at STP would be 1 6 022 1023 3 6 022 1023 5 2 6 022 x 1020 4 6 022 1022 2

In a space shuttle the CO2 output per astronaut has been estimated as 44g hr An experimental catalytic converter reduces CO at a rate of 600 ml STP per minute into H O What fraction of time would such a converter have to operate in order to keep up the CO output of one astronaut