General Questions and Answers

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

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

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

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

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

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

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

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

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

When mercuric iodide is added to the aqueous solution of KI then the 1 Freezing point is raised 2 Freezing point is lowered 3 Freezing point does not change 4 Boiling point does not change

There are four solvents A A Ag and A4 The dielectric constants of the solvents follow the order Ag A A A Among them only A and A are capable of forming hydrogen bonds Which of the solvents will be most suitable for Sw1 reactions A A C A3 B A D A4

Select the correct option s about valence Bond Theory regarding co ordination compounds It does not explain visible spectra of complexes It is not able to explain diamagnetic behaviour of Co H O 6 Cl3 even Co is paramagnetic It is unable to differentiate between weak and strong field ligands It makes exact predictions regarding the tetrahedral and square planar structures of 4 coordinate complexes

1 Which of the following compounds has a negative enthalpy of solution 1 KCI 2 KBr small size of peion it here maxim Eve enthalpy of Solution 3 KF 4 KI 22 X X AH 720k1 mol 1

Glycerol on oxidation with dil HNO3 gives 1 tartronic acid 2 mesoxalic acid 3 oxalic acid 4 glyceric acid 2 3 CH 0 How many moles of HI consumed in above reaction 1 1 2 2 3 3 4 4 CH CH CH 5 OH Falcohol CH Find missing reagents 1 x LiAlH4 y NaBH4 2 x LIAIH4 AICI3 y LIAIH4 3 x LIAIH4 Y LIAIH4 AICI3 4 x H Ni y H Pt 3 Aluminium isopropoxide 4 Acetone CH CH OCH 1 200 2 2 HCOOH CH CH CH CH CH OH 2 akohol H COH CH OH on heating with per iodic acid gives I 3 CHO 4 Which of the following reagents would distinguish cis cyclopenta 1 2 diol from the trans isomer 1 ozone 2 MnO 4 6 7 H c 0 2 I CH Mgl i H O The compound Y in the above sequence is 1 2 Methyl 2 phenyl 1 propanol 2 2 Phenyl 2 propanol 3 Acetophenone 4 2 Methyl 1 Phenyl 2 propanol 8 What is X 1 CHO 3 4 CH 3 CH3 CH B Predominant OH CH MgBr excess PBes X H O OH OH Cu 575 K CH3 Y x OH OH

15 The variation of the boiling points of the hydrogen halides is in the order HF HI HBr HCI What explains the higher boiling point of hydrogen fluoride 1 The bond energy of HF molecules is greater than in other hydrogen halides 2 The effect of nuclear shielding is much reduced in fluorine which polarises the HF molecule 3 The electronegativity of fluorine is much higher than for other elements in the group 4 There is strong hydrogen bonding between HF molecules

The compound has two atoms X and Y its cubic crystal structure X atom in the water at the corners of the unit cell and Y atomic work is at the centre Its simplest formula is 1 x y 2 XY 3 XY 4 XXY

2 S 3022SO3 AH 791 4 kJ When 6 4 g of Oxygen are reacted with excess sulfur and 52 760 J are released What is the q value of the reaction If this reaction occurs in 300 ml of water that began at 25 3 C what would be the final temp

A commercially valuable paint and adhesive stripper DMSO can be prepared by the reaction of exygen with dimethyl anders using a s of one mole oxygen to two moles of the sulfide O 2 CH S 2 CH SO atomic mass of S C and O are 32 12 and 16 respectively Question 28 If the process is 100 efficient weight of O in gram that is used up with 65 g of dimethyl sulfide DA15 46 g B 16 77 g Oc 14 64 g b 15 89 g

Mean bond enthalpy of C H bond is 416 kJ mol 1 AaHo fo CH4 is 416 kJ mol 1 416 kJ mol 1 1664 kJ mol 1 1664 kJ mol 1

14 Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules Fo 010 YOU O 019

32 The correct order of energies of d orbitals of metal ion in a 32 square plannar complex is 1 d d d 2 d d d d d 3 d d ayd

4 In Na Fe CN NO sodium nitroprusside ipt 1 oxidation state of Fe is 2 2 this has NO as ligand 3 both are correct 4 none is correct

A body of mass 2 kg moving with a velocity i 2j3k ms collides with another body of mass 3 kg moving with a velocity 21 3 k ms 14 If they stick together the velocity in ms of the composite body is 1 8 73 3k 2 4i j 3k 3 1 8i j k 4 4i 73 3k 120

A proton accelerated from rest through a potential difference of V volts has a wavelength associated with it An alpha particle in order to have the same wavelength must be accelerated from rest through a potential difference of A V volt C 2V volt B 4V volt V 8 D volt

3 Which is incorrectly given according to order indicated 1 F2 C12 Br2 12 Oxidising power 2 HI HBr HCI HF Acidic strength 3 F2 C12 Br2 12 Bond dissociation enthalpy 4 HF HI HBr HCI Boiling point

53 Three isotopes of an element have mass numbers m m 1 and m 2 If the mean mass number is m 0 5 then which of the following ratios may be accepted for m m 1 m 2 in that order k a 1 1 1 c 3 2 1 54 The radii of 5 4 1 1 d 2 1 1

22 Select the correct statement s from the following 1 Fluorine displaces other halogens from the corresponding halides 2 Fluorine reacts slowly with halogens 3 Fluorine does not decompose water 4 Except fluorine other halogens directly combine with carbon

dt dt 2 The rate constant does not depend upon concentration for reaction whose order is c second a zero b first d third 3 If the rate law does not contain a concentration term then the order is b first Seco econd d third 37

The electron affinity of fluorine is less than that of chlorine because A The incoming electron enters the 3p orbital in fluorine B The incoming electron enters the 2p orbitals in fluorine and 3p orbital in chlorine The electron density in fluorine is higher D Fluorine has lower ionisation potential than chlorine

Q2 Air at 45 C and 25 relative humidity enters water spray tower at rate of 90 m hr The air is adiabatically humidified to 50 relative humidity Use psychrometric chart to find 1 Outlet temperature of the humidified air 2 Rate of water evaporation in the water spray tower

112 During the titration of a weak diprotic acid H A against a strong base NaOH the pH of the solution half way to the first equivalent point and that at the first equivalent point are given respectively by a pK and pK a a c pKa and PK pKa 2 13 In which of the following cases is the solution of AgCl unsaturated pK a q b KC and 92 PK pk a 2 d pK and pK a2 92

mergy released O g 2e 2e 0 AHeg 744 7 KJ mole The positive value of AHeg is due to g A Energy is released to add on 1 e to 0 B Energy is required to add on 1 eto 0 is much more than energy released when le is added toO g C Energy is needed to add on le to O D None of the above is correct

If you are reacting 4 00 g benzophenone MM 182 22 g mol and you want to add 1 5 equivalents of NaBH4 MM 37 83 g mol what is the minimum volume in mL of 2 0 M HCl you need to add to ensure the reaction is fully quenched

56 When photons of energy 4 25eV strike the surface of a metal A the ejected photoelectrons have maximum kinetic energy TA expressed in eV and de Broglie wavelength 24 The maximum kinetic energy of photoelectrons liberated from another metal B by photons of energy 4 70V is Tg TA 1 50 eV If the de Broglie wavelength of these photoelectrons is AB 224 then which is not correct a The work function of A is 2 25 eV b The work function of B is 3 70 eV c TA 2 00eV d TB 0 5eV

A mol L 2 5 10 4 5 0 10 4 1 0 10 3 B Initial rate mol L 1 at mol L 300 K 320 K 3 0 10 5 5 0 x 10 4 2 0 x 10 3 6 0 10 5 4 0 10 3 6 0 10 5 1 6 10 a Calculate the order of the reaction with respect to and with respect to B b Calculate the rate constant at 300K c Calculate the pre expontential factor

6 The correct order of acidic strength is 1 HCIO4 HCIO3 HCIO2 HCIO 2 HCIO3 HBrO3 HIO3 3 H3PO2 H3PO3 H3PO4 4 All of these

D 786 999 1012 1256 Which of the following sequence is correct for decreasing order of ionic radius A Se 2 I Br O 2 F C Se 2 I Br F 0 2 B I Se 2 O 2 Br F D Se 2 Br 0 2 F Which 11

In an experiment one mole of Na2CO3 10H2O was heated to a temperature by which it got converted into Na2CO3 xH O The H O vapours obtained in this process were used to convert CuSO4 into CuSO4 5H O If 0 6 moles of CuSO4 was hydrated value of x is

The ionic radii of Ni Pd Pt2 are given below Radius in ions Ni2 0 72 1 44 1 48 Pd pt2 60 Ionic radius is increases from Ni2 to Pd but Pd to Pt ionic radius is almost constant This is due to 1 Poor sheilding of 4f electrons towards 7s 2 Imperfect sheilding of 4f electrons towards 6s electron 3 Poor screening of 5f electrons towards 7s 4 All of these

A sample of gas expanded isothermally from 1 L to 10 L against constant external pressure of 1 atm The work done during the process is 1 L atm 9 L atm 10 L atm

aqueous solution of sodium hydroxide contains 2 00 g NaOH in 50 0 mL of solution the number of moles of NaOH present equals the molar concentration of the solution is how many moles of NaCl would be formed if 50 0 mL of 1 0 mol L HCI solution were added to the 50 0 mL of NaOH solution

Solubility of Ni OH 2 will be maximum in 0 1 M aq solution of NiS 0 1 M aq solution of NaOH 0 1 M aq solution of Ca OH 2 0 1 M aq solution of H SO4

9 15 The transition in He ion in balmer series that would have the same wave number as the first Lyman line in the hydrogen spectrum is Final Results 0 2 1 0 5 3

A square array of 196 tubes 1 25 cm in diameter is used to condense steam at 1 atm pressure Water flowing inside the tubes maintains the outside surface temperature at 92 C Calculate the condensation rate for tube lengths of 2 0 m

HBPB OH The times required to consume a small but constant amount of HBPB at varying initial HBPB and OH concentrations were measured and are recorded below Determination 1 1 The following data were collected at 20 C for the reaction of bromphenol blue HBPB2 and hydroxide ions OH is shown below 2 3 3 BPB H O HBPB M 7 22 x 106 7 22 x 10 3 63 x 10 OH M 1 00 0 25 1 00 Rate 2 Rate 1 k A B k A B Time s 75 290 152