General Questions and Answers

A catalyst in the finely divided form is most effective because 1 less surface area is available 2 more active sites are formed 3 more energy gets stored in the catalyst 4 none of these

When benzoic acid heated in presence of NH3 a product X is formed Reaction a X Br KOH Reaction b Y CHCl3 KOH Y other products C Z other products If initially 1 mole of benzoic acid is taken then find the sum of total number of moles of products formed in balanced reactions a and b 19 00

w fdv Pext For a system undergoing a particular process the work done is a w jav V 2 RT V b V This equation is applicable to a A System that satisfies the van der Waals equation of state B Process that is reversible and isothermal C Process that is reversible and adiabatic D Process that is irreversible and at constant pressure

In a reaction for every 10 C rise of temperature the rate is tripled If the temperature is increased from 10 C to 50 C the rate of the reaction will become O 81 times O 9 times O 243 times

Find out the number of photons emitted by a 60 watt bulb in one minute if wavelength of an emitted photon is 620 nm a Calculate the kinetic energy of a photoelectron emitted by a sodium surface when light of wavelength 400 nm is incident on it The work function of sodium is 2 28 eV

Chemistry Classify following solutions in to true solution colloid and suspensions Write names of solute and solvent present in any five from these solutions Milk Paint Blood Lemonade Salt solution Rain water Coke Air Tooth paste Shaving cream Gem stones Tea Cold coffee

Given Enthalpy of ionization of two acids AH HCN 45 2 kJ mol AH CH COOH 2 1 kJ mol Which relationship for the two acids is true 1 pK HCN pK CH COOH 2 pK HCN pK CH COOH 3 pK HCN pK CH COOH 45 2 2 1 4 pK HCN B pK CH COOH 80 faci AH HCN 45 2 facile i AH CH COOH 2 1 kJ f 1 pK HCN pK CH COOH 2 pK HCN pK CH COOH 3 pK HCN pK CH COOH 45 2 4 pK HCN 2 1 pK CH COOH

2 The conductivity of four electrolytes P Q R S in ohm cm are as follows P 5 x 10 Q 1 x 10 0 R 7 x 108 S 9 2 x 10 The one which offers highest resistance to passage of electric current is 1 P 3 R 2 S 4 Q

A cubic solid is made of two elements P and Q Atoms of Q are at corners and face centres of the cube and P at all octahedral voids then the coordination numbers of P and Q respectively are 4 and 4 1 and 1 8 and 8 6 and 6

A Among the following species identify the isostructural pairs NF3 NO3 BF3 H3O HN3 1 NF3 NO3 and BF3 H3O 2 NF3 HN3 and NO3 BF3 3 NF3 H3O and NO3 BF3 4 NF3 H3O and HN3 BF3

nm is incident on it The work function of sodium is 2 28 eV b Calculate the value of the longest wavelength which can result in the emission of a photoelectron from a sodium surface Ultraviolet light of wavelength 280 nm is used in an experiment of photoelectric effect with lithium w 2 5 eV cathode Find

For the chemical reaction 2 HI g H g 1 g The incorrect option is O 1 1 d HI d H 2 dt dt O 1d HI d 2 dt d HI dt d H d dt dt dt 1 d H 2 dt

In 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 The molar mass of acid is O 59 O 60 O 39 10

8 The activation energy of a first order reaction at 27 C is 54 kJ mol In the presence of a catalyst the activation energy of the same reaction lowers to 44 kJ mol at 27 C How many times the reaction rate changes in the presence of a catalyst at 27 C 9 The specific rate constant for the reaction of H with I to form HI is 0 43 at 673 K If the activation energy is 171 5 kJ mol what is the rate constant at 773 K

Please explain in detail what is levelling effect and what i s levelling solvent Also do we have to learn the relative strength of different acids o auto n Any substance such as water which may function as an acid as well a base is called amphoteric Strength of all strong acids HCI H SO HNO HCIO etc in water is same and become equal to the strength of H O ion This is called levelling effect of water So strength of strong acids is compared in glacial acetic acid Water is called levelling solvent and glacial acetic acid is called differentiating solvent for strong acids Levelling effect of water is due to its high dielectric constant and strong tendency to accept protons Strength of all strong bases in water is the same and becomes equal to the strength of OH ion because of levelling effect of water Any acid having acid constant K greater than 1 may be regarded as strong acid Relative strength of acids in glacial acetic acid follows the order HCIO HI HBr H SO HCI HNO H O H PO HF CH COOH H CO H S HCN The strongest acid known is HCIO and strongest base known is CSOH

An ionic solid A Be crystallizes as a bc structure The distance between cation and anior in the lattice is 338 pm Calculate the edge length of the unit cell 1 195 15 pm 2 97 58 pm 3 390 3 pm

A 54 35 pm In diamond carbon atom occupy FCC lattice points as well as alternate tetrahedral voids If edge length of the unit cell is 356 pm then radius of carbon atom is A 77 07 pm B 154 14 pm C 251 7 pm D 89 pm

Which of the following cations posses neither noble gas nor pseu i Bi ii Pb iii Sn 1 ii iii 2 i iv 3 i ii iii U 18 ations iv Tl 4 i ii iii iv

Among the complex ions Cr CO 6 Fe CO 5 PtCl Br CO NH3 3 NO3 3 Fe H O 4 OH 2 Fe NH3 2 CN 4 Co NH CH CH2 NH2 2 NH3 CI 2 and Co NH3 4 H O CI 2 the number of complex ion s that show s cis trans isomerism is Answer 00 01 02 03 04 05 06 07 08 00 01 02 03 04 05 06 07 8 9

7 Total number of compounds that can be taken as a reagent in the titration of boric acid with NaOH is nic acid w HIS RAYANA GROU Ethylene glycol glycerol transcyclopentan 1 2 diol salicyclic acid glucose mannitol cis cyclohexane 1 2 diol

The ionisation constant of an acid K is the measure of strength of an acid The K values of acetic acid hypochlorous acid and formic acid 1 74 x 10 3 0 x 10 and 1 8 x 10 respectively Which of the following orders of pH of 0 1 mol dm solutions of these acids is correct are i acetic acid hypochlorous acid formic acid hypochlorous acid acetic acid formic acid

ALLEN 88 For one mole of vanderwal s gas when b 0 and 88 1 V T 300K the PV vs The value of vanderwaal constant a is 1 1 0 2 4 5 3 1 5 PV 24 6 21 6 20 1 plot is shown below 2 0 3 0 che 1 V fraic 25 1 1 2 4 3 1

1 mol of FeC O4 is oxidised by x mol of Cr O in acidic medium then x is 1 3 2 1 5 3 0 5 4 1 0 82

3 253 kJ mol 4 313 kJ mol 10 ml each of IM HCI and IM H SO are 79 neutralised by IM NaOH solution that liberate the heat of x and y respectively Which is true 1 2x y 2 x y 3 x 2y 4 3x y 3 253 kJ mol IM HCI IM H SO face and artiq rufaa 1 2x y 3 x 2y 4 313 kJ mol t mol 10 ml IM NaO xay 35 2 x y 4 3x y

16 Determine the value of AH and AU for the reversible isothermal evaporation of 90 0 go water at 100 C Assume that water vapour behave as an ideal gas and heat of evaporatio of water is 540 cal R 2 0 cal mol K B

and O2 2gm each Because of a sudden sparking inside the container the gases reacted with ea The vapour pressure of water at 27 C is 45mm Hg A closed container of volume 1 L is filled with other with 100 efficiency Calculate the partial pressure of gases remaining and total pressure the container finally at 27 C

Antimony is obtained by heating pulverized stibnite Sb S3 with scrap iron and drawing off the molten antimony from the bottom of the reaction vessel Sb S3 3Fe 2Sb 3FeS Suppose that 0 600 kg of stibnite and 0 300 kg of iron turnings are heated together to give 0 300 kg of Sb metal Calculate a The limiting reactant b Excess reactant c The degree of completion d The percent conversion e The yield

What is the oxidation number of titanium Ti 48 Spinel is a important class of oxides consisting of two types of metal ions with the oxide ions arranged in CCP pattern The normal spinel has one eight of the tetrahedral holes occupied by one type of metal ion and one half of the octahedral hole occupied by another type of metal ion Such a spin l is formed by Zn Al and 0 with Zn in the tetrahedral holes Give the formulae of spinel

Choose the correct statement among the following O Number of formula units of CsCl per unit cell in CsCl structure is 4 Co ordination number of fluoride ion in fluorite type structure is 4 Number of formula units of NaCl per unit cell in rock salt structure is 1 Co ordination number of chloride ion in rock salt type structure is 2

I think I have made no mistake then too why my answer is not matching with answer key Please help me 3 102 00 9 2 g of toluene C Hg is completely burnt in air The difference in heat change at constant pressure and constant volume at 27 C is 1 2 5 kJ 2 2 5 kJ 3 Zero 4 0 50 kJ For the reaction P Q 3YAH nCPAT PUENGAT AH AU NAT CP C a Load pat tznate to ex ZMATR 10 21x300x25

For most of the transition metals of first series the magnetic moment is nearly equal to spin only magnetic moment This is due to The contribution of orbital angular momentum is very high so it plays important role in measurement of magnetic moment The contribution of orbital angular momentum is effectively quenched so orbital angular momentum have no significance in magnetic moment Most of the metals or metal ions are diamagnetic in nature O Most of the metals or metal ions are coloured in nature

If the resulting potassium carbonate weighs 0 745 g and the calculated yield is 0 690 g what is the percent yield General Exercises percent V AXO SZA

6 Match the following Column I A Vitamin B12 B Wilkinson catalyst C Blood pigment D Ziegler Natta catalyst 1 A c B e C b D d 2 A d B b C e D a 3 A c B e C b D a 4 A b B c C e D a Column II a Ti b Fe c Co d Mg e Rh K

3 32 g of methane gas initially at 101 325 kPa and 300 K is heated to 550 K Given Cp m JK mol 12 552 8 368 x 102T K Assuming that methane behaves ideally calculate w q AE and AH for an isobaric reversible process 5

on a clear day at sea level with a temperature of 25 degrees Celsius the partial pressure of N2 in air is 0 78 atm and the concentration of nitrogen in water is 5 3 x 10 4 M When the concentration in water is 1 1 x 10 3 M what is the partial pressure of N2

A certain sample of cuprous sulphide is found to have the composition Cu S because of incorporatio 1 92 of Cu ions in the lattice What is mole percent of Cut in total copper content in the cyrstal A 95 8 B 92 C 8 D 4 17

When alpha particles are sent through a thin metal foil most of them go straight through the foil because A alpha particles are much heavier than electrons C most part of the atom is empty space B alpha particles are positively charged D alpha particles move with high speed For a wave frequency is 10 Hz and wavelength is 2 5 m How much distance it will travel in 10

13 At 100 C copper Cu has FCC unit cell structu with cell edge length of x A What is th approximate density of Cu in g cm at th temperature Atomic Mass of Cu 63 55 u JEE Main 201 1 3 422 X 105 X 4 205 211 X

Example 1 3 An element has a body centred cubic bcc structure with a cell edge o 288 pm The density of the element is 7 2 g cm How many atoms ar present in 208 g of the element Solution Volume 11 1099

Consider a 100 gm oleum sample which is labelled as 110 H SO4 After adding only sufficient amount of water that can react only with free SO3 If x grams of pure H SO4 can be obtained from the solution Then the value of x 100 is 2

Consider the change in oxidation state of bromine to different emf values as shown in the corresponding given diagram BrO 1 82 V Bro BrO3 1 0652 V Br 1 5 V HBrO 1 595 V Br Then the species undergoing disproportionation is a BrO b Bro c Br d HBrO

9 According to the lesson who was the audience when Bismillah Khan poured his heart out into Raag Kafi from the Red Fort 0 5 Points a Pandit Jawaharlal Nehru b Mahatma Gandhi c Rajendra Prasad

1 The enthalpy of hydrogenation of cyclohexene is 119 5 kJ mol If resonance energy of benzene is 150 4 kJ mol its enthalpy of hydrogenation would be A 208 1 kJ mol B 269 9 kJ mol C 358 5 kJ mol D 508 9 kJ mol

An element has a face centred cubic fcc structure with a cell edge of a The distance between the centres of two nearest tetrahedral voids in the lattice is JEE Main 2019 1 NEW a NON 3 a 2 N O 4 2a

Solid State A solid A and B had NaCl type closed packed structure If the anion has a radius of 250 pm what should be the ideal radius of the cation Can a cation C having a radius of 180 pm be slipped into the tetrahedral site of the crystal of A B Give reasons for your answer KF crystallizes in the NaCl tyng

QUESTION 4 Calculate the equilibrium constant of below reaction NH Cl aq Na2S aq H2O l NH3 H2O aq NaHS aq NaCl a Knew K and K of H S are 10 7 2 and 10 14 K of NH4OH is 10 4 76 and Kw 10 L

Its C Different than the order May be same or different as compared to order 1 3 A gaseous compound A reacts by three independent first order process as shown in figure with rate constant 2 x 10 1 93 x 10 sec and 3 x 103 sec respectively for products B C and D respectively If initially pure A was taken in a closed container with P 8 atm then partial pressure of B in atm after 100 sec from start of experiment A 0 228 C 1 154 B 0 577 D none A g k k B g D g C g

Identify the incorrect statement 1 Gangue is an ore contaminated with undesired materials 2 The scientific and technological process used for isolation of the metal from its ore is known as metallurgy 3 Minerals are naturally occurring chemical substances in the earth s crust 4 Ores are minerals that may contain a metal

11 Assertion A spherical water drop becomes flat on flat surface Reason It becomes flat due to gravity b a If both assertion and reason are true and reason is the correct explanation of assertion If both assertion and reason are true but reason is not the correct explanation of assertion c If assertion is true but reason is false d If both assertion and reason are false

Earlier Model of Atom Wave Theory 1 The mass to charge ratio for A iobns is 1 97 x 10 7 kg C 1 Calculate the mass of A atom 2 Atomic radius is of the order of 10 8 cm and nuclear radius is of the order of 10 13 of atom is occupied by nucleus cm Calcula