General Questions and Answers

24 Calcium phosphide Ca P formed by reacting magnesium with excess calcium orthophosphate Ca PO was hydrolysed by excess water The evolved phosphine PH was burnt in air to yield phosphrous pentoxide P O How many gram of magnesium metaphosphate would be obtain if 192 gram Mg were used Atomic weight of Mg 24 P 31 Ca PO Mg Ca P MgO 2 Ca P H O Ca OH PH 2 PH O P O5 H O 3 2 MgO P 05 Mg PO3 motaphosphate

14 Latent heat of vaporization of a liquid at 500 K and 1 atm pressure is 10 0 kCal mol What will be the change in internal energy of 3 mol of liquid at same temperature and pressure A 13 0 kCal C 27 0 kCal B 13 0 kCal D 27 0 kCal

16 The volume 80 m cylinder contains oxygen gas at a temperature of 280 K and a pressure of 300 kPa Determine the a mass of oxygen in the cylinder b the number of oxygen molecules in the cylinder c the rms of oxygen in the cylinder Ans a 320 90 kg b 6 209 x 1027 c 467 m s

A balloon is filled to a volume of 7x10 ml at a temperature of 20 degree Celsius The ball oon is then cooled at a constant pressure to a temperature of of 1 00 10 K What is the final volume of the balloon

1 A vessel of volume 22 4 dm contains 2 0 mol H and 1 0 mol N at 273 15 K Calculate a the mole fractions of each component b their partial pressures and c their total pressure Ans a 0 666 0 333 b 2 0004 1 0002

17 The equivalent conductivity of 1M H SO4 solution would be if specific conductance is 26 10 2S cm 1 1 1 3 10 S cm eq 2 1 6 10 S cm 1 3 13 S cm mol 1 4 1 3 x 10 S cm mol 1 2 1x30x5 35 5 9650

4 Using the average pk value calculated in 3 calculate the pH of the pH 7 0 buffer solution that is expec after the addition of 1 0 mL of 1 0 M HCI and 1 0 mL of 1 0 M NaOH compare to the actual measured pHs after the addition of the H or OH How do these calculated p Explain your results and show your calculations PKa 6 793

The standard deviation in a method for the determination of substance a in a given sample has been found to be 0 03 ppm How many measurements should be made if the 95 confidence level z 1 96 is to be 0 017 A 12 C 13 B D 9 10

If 5 ampere of current is passed through a solution for 10 hours the the number of electrons flown through the solution is Charge of electron 1 6 10 1 C O 6 02 x 1025 1 1 x 1024 O 1 8 x 106

4 In a mixture of 13 g H 60 g of N and 3 g of NH3 calculate a number of moles of each component b mole fraction of each component and c how many molecules are present in each case Ans a 6 44 2 14 0 176 b 0 7354 0 2444 1 541 5 Determine the ratios of a the mean speeds b the mean kinetic energies of He atoms

The same amount of electric current is apassed through aqueous solution of MgSO4 and AICI3 If 2 8 g Mg metal is deposited at amount of Al metal deposited in second cell will be 1 2 1 g 2 2 49 g 3 3 15 g 4 3 73g

3 On a cold dry morning after a frost the temperature was 5 C and the partial pressure of water in the atmosphere fell to 0 30 kPa Will the frost sublime What partial pressure of water would ensure that the frost remained Ans the frost will sublime

A 2 7 gm sample of pure aluminium is heated in a stream of O2 gas for some time resulting in gain in weight due to formation of Al2O3 The final weight is 4 86 gm Select correct option s Al 27 O Percent of aluminium that remains unoxidized is 90 Percent of aluminium that remains unoxidized is 10 O Percent of aluminium that is oxidized is 90 Percent of aluminium that is oxidized is 80

an organic acid Molecular mass 90 reacts with excess of silver nitrate to form a precipitate of mass 15 2 g of its silver salt On heating this precipitate 10 8 g residue is obtained The basicity of the organic acid is Ag

Ozone is unstable with respect to decomposition to ordinary oxygen 203 g 302 8 K 1 3 x 1057 How many ozone molecules are present in the atmosphere at equilibrium in 17 86 million cubic meters of air at 24 6 C and 610 7 mmHg Record your answer with no decimals

In an analysis the complete combustion of 174 2 mg of compound A produces 490 6 mg of carbon dioxide and 201 1 mg of water vapour Compound A contains carbon hydrogen and oxygen Determine the empirical formula of compound A Use the molar masses from the textbook I have assigned for the course Empirical formula of compound A

11 A metal can of volume 2000 0 cm3 contains 2 0 g of nitrogen gas and 6 0 g of hydrogen gas at exactly 200 C What is the total pressure of gas in the can Ans 6 MPa 12 The product of the pressure and volume of a sample of hydrogen gas at 0 00 C is 80 0 I Ans a 0 0352 mol b 565 x 10721 c 138 42 11

Hydrocarbon contains 600 by mass carbon and its one molecule weighs 93 33 x 10 24 g Which of the following statement s is are correct NA 6 0 x 10 7 O Empirical formula is CH O Empirical formula is CH2 O Molecular formula of C3Hg O Molecular formula is C4H8

The electronic configuration of the element which is just above the element with atomic number 43 in the same periodic group is A Ar 3d 4s B Ar 3d 0 4s 4p5 C Ar 3d4s D Ar 3d 4s 4p E Ar 3d 4s

No 12 A solution containing a metal complex absorbs at 480 nm with molar extinction coefficient of 15 000 L mol cm If the path length of the cell is 1 0 cm and transmittance is 20 5 the concentration in mol L of the metal complex is 1 37 10 5 2 29 10 5 4 59 x 10 5 8 75 x 10 5 A B C D

75 Dimerisation of NO is an exothermic reaction If enthalpy of reaction is AH then the minimum value of activation energy for forward reaction E will be 1 Equal to AH 2 Equal to zero 3 Greater than AH 4 Greater than Threshold energy 2

A straight glass tube of length 450cm has two inlets X and Y Through inlet X the gas with vapour density 36 and through inlet Y an unknown gas are introduced at same time and same T and P The distance of point at which two gasses meet is 180cm from the end X what is the weight of 2 8lit of that gas in grams at STP

If x gram of oxalic acid can completely be oxidised by 400 ml of 0 1M acidified permanganate solution according to the following equation then value of x is MnO C 0 H Mn CO H O

55 10 g of each Pb Al Ag and Cu is given 100 kJ of heat and temperature rise is x y z and w kelvins respectively Then select the correct relation given heat capacity in J g k is 0 9 0 386 0 233 and 0 128 for Al Cu Ag and Pb respectively 1 x y 3 z w 2 y w 4 x z

The correct name of the compound Cu NH NO3 according to IUPAC system is O Tetraamminecopper II dinitrite Tetraamminecopper II nitrite O Cupraammonium nitrate

of this mole 329 3 25 00 mL sample of a household cleaning solution was diluted to 250 0 mL in a volumetric flask A 50 00 mL aliquot of this solution required 41 27 mL of 0 1943 M HCI to reach a bromocresol green end point Calculate the mass volume percentage of NH3 in the sample Assume that the alkalinity results from the ammonia N 14 00 H 1 01 Cl 35 5 g mol LE

73 Which of the following pair of species illustrates law of multiple proportions 1 02 03 2 H O D O 3 CH4 C H 4 KOH KCI of Ma is 24 amu it means that an

Marks 0 In all other cases A collection of H atoms in 9th excited state returns to ground state Find the ratio of total number of spectral lines emitted without emitting any line in Brackett series to number of Brackett series lines

What would be percentage packing efficiency of the smaller cubes formed within a F C C arrangement by joining centres of the tetrahe voids Take 0225 0 0114 0 414 0 0710 0 732 0 392 1 414 2 83 3 1 05 O 12 22 48 02 58 07 23 58

Another application for dilutions A 24 hour urine for creatinine measurement frequently requires dilution In this example 1800 mL of urine is provided in 24 hours Before measurement the urine is diluted 1 5 and the result is 26 mg dL To calculate the final concentration based on total excretion in the 24 hour period use the following equation Total excretion total urine volume x concentration x dilution Total excretion 1800 ml 24 hr x 26 mg dL x 5 x dl 100 mL Total excretion 2340 mg 24hr or 2 34 g 24 hr 4 Calculate the 24 hour excretion of creatinine if the urine volume is 2 5 L The specimen was diluted 1 4 before measurement The measured creatinine concentration was 25 mg dL What is the total excretion in mg 24 hrs

Compound A has the molecular formula C5Hg and is optically active Or catalytic hydrogenation A yields B Compound B has the molecular formula C5H10 is optically inactive and cannot be resolved into separat enantiomers Compound C has the molecular formula C6H 0 and it is optically active Compound C contain no triple bonds Catalytic hydrogenation of C yields D Compound D has the molecular formula C6H14 is optically inactive and cannot be resolved into separate enantiomers Select the correct statement A and C both are cyclic compounds O Compound C may be allene Compound A may be allene Compound D has less boiling point than neohexane

organic acid Molecular mass 90 reacts with excess of silver nitrate to form a precipitate of mass 15 2 g of its silver salt On heating this precipitate 10 8 g residue is obtained The basicity of the organic acid is Ag 3

3 A mixture of benzene and toluene contains 30 by mass of toluene At 30 C vapour pressure of pure toluene is 36 7 mm Hg and that of pure benzene is 118 2 mm Hg Assuming that the two liquids form ideal solutions calculate the total pressure and partial pressure of each constituent above the solution at 30 C 867 mm D 065 www

From the following reaction sequence CaC2 H2O CaO C2H2 C H H C H4 nC H4 C H4 n Calculate the maximum mass of polythene in kg which can be obtained from 32 kg of Calcium carbide CaC2 if overall yield of reaction

Which of the following are correct Clear Respons H Ne 0 F SO order of rate of diffusion at same T and P lg H lg He lg CH 1g0 total K E at same T U average Umpv value of velocities U rms order of N 0 0 SO order of average K E

Ultraviolet light of wavelength 280 nm is used in an experiment of photoelectric effect with lithium w 2 5 eV cathode Find a Maximum K E b Stopping potential The there hold frequency for a motalic 6 x 1014 1 O

The ionisation energy of second electron in helium atom is A 100eV B 27 2eV C 13 6eV D 54 4eV heyl am confused from this question mujhe pata hai electron ko remove karane ke liye ionisation energy 54 4 ev di jaayegi but I am confused whe he ask of 2nd electron ionisation energy in helium mujhe janna tha ki ionisation energy of 1st electron and 2 electron me difference hai kya kuch

A gas is flowing through an isentropic nozzle The gas enters the nozzle at 7 MPa and 450 and exits at 1 MPa The gas has been found to follow the truncated virial equation An expression for the second virial coefficient is B T 4 992 x 10 673 0 00743 7 3 96599 T 776 807 where T is in K The heat capacity of the gas follows the equation Cp A BT CT DT where A 1 98 x 10 B 7 344 x 102 C 5 602 x 105 D 1 715 x 10 8 1 At what temperature does the gas exit the nozzle 2 What is the gas velocity at the exit of the nozzle

The statement which is not correct about pe troleum 1 petroleum is a kind of fossil fuel s 2 petroleum is accumulated beneath sed imentary rocks 3 petroleum is called petro I for short 4 various types of liquid fuels ar e made from petroleum

A sample of crystalline soda with a mass 2 574 gm was allowed to react with an excess of hydrochloric acid and 204 3 cm of gas was liberated at 1 bar pressure and 0 C What is the number of water of crystal molecules in one molecule of soda

When electromagnetic radiation of wave nature is considered an atom is emitted light continuously and Maxwell thought that electron has stationary like Thomson But in reality electron emit light continuously when it moves with velocity if also wave nature of electromagnetic radiation we

n 12 gm of mono basic organic acid 4 8 gm carbon 0 8 gm hydrogen and 6 4 gm oxygen present 0 8 gm of silver salt of same monobasic organic acid left a residue of 0 5175 gm of silver on ignition Molecular formula of acid is O CH

Q 13 A metal forms two oxides The higher oxide contains 80 metal 0 72 g of the lower oxide gave 0 8 g of higher oxide when oxidised Then the ratio of the weight of oxygen that combines with the fixed weight of the metal in the two oxides will be Choose answer 02 3 1 2 045 03 2

Write the mass to two places beyond the decimal point of each component at the end of the reaction in the boxes on the bottom of the page Show your work Na3C6H5O7 3 CO 258 g mol 3 NaHCO3 14 39 84 0 g mol 4 00 g H3C6H5O7 9 00g 192 g mol 5 00 g 44 0 g mol 3 H O 18 0 g mol

Sulphate of metal M does not form precipitate with dil HCI but it forms black ppt P when H S gas is passed in presence of dil HCI P is insoluble in ammonium polysulfide Sulphate of metal M on reaction with small amount of NH4OH give precipitates and this become a soluble deep blue solution Q when excess of NH3 is passed Solution Q on acidification with acetic acid and then adding potassium ferrocyanide solution gave a chocolate brown precipitate R Select the correct statement Metal M belong to 4 th period of modern periodic table Precipitate P is insoluble in nitric acid IUPAC name of Q is tetraamminecopper III sulphate IUPAC name of R is copper hexacyanoferrate III

Given the numbers 161 cm 0 161 cm 0 0161 cm The number of significant figures for the three numbers is a 3 3 and 4 respectively b 3 4 and 4 respectively c 3 4 and 5 respectively d 3 3 and3 respectively 1998

50 E values of Mg2 Mg Zn Zn and Fe Fe are 2 37 V 0 76 V and 0 44 V respectively Which of the following is correct 1 Mg2 oxidises Fe 3 Zn reduces Mg2 2 Zn oxidises Fe2 4 Zn reduces Fe

Eal 1 A B Ea 1 Sandton Hoq a 2 20 Ea 2 G H 11 modoss a step 2 is rate determining Given the activation energies E 1 120 kJ mol E 96 kJ mol a For the mechanism E a 2 196 kJ mol find E a A 154 C D for the overall reaction 2A 2B2D G H som omlet paid to C 354 B 244 3 D None of these

8 3 5 R in 2 4 R In 2 2 The enthalpy of atomisation of PH is 954 kJ 78 mol and that of P H is 1485 kJ mol What is the bond enthalpy of the P P bond 1 213 kJ mol 2 200 kJ mol 3 253 kJ mol 4 313 kJ mol 10 ml each of IM HCI and IM H SO are 79 3 5 R In 2 4 R In 2 PH P H 1485 kJ mol P P vtt 1 213 kJ mol 3 253 kJ mol IM HCI IM H SO 954 kJ molta 2 200 kJ mol 4 313 kJ mol 10 mi IM NaO

The paramagnetic property of the oxygen molecule is due to the presence of unpaired electrons present in 1 02 and 2 2 02 and 3 2 and 2