General Questions and Answers

3 25 min 50 min 4 250 mi For an elementary reaction X g Y g Z g the half life period is 10 min In what period of time the concentration of X will be reduced to 10 of original concentration 1 20 min 2 33 min 3 15 min 4 25 min on is 75 completed in 100 min How long will it take for it s 87 5 completic 0 200 min

Find the hydrolysis constant of NaX if the dissociation constant of weak acid HX is 2x10 5 Ans 5x10 10

Cations of group IA and group IIA elements are diamagnetic and colourless since their orbitals do not contain odd electrons

In a solid AB having the NaCl structure A atoms occupy the every ccp and B atoms are in OHV If all face centred atoms along one of the axes are removed then the resultant stoichiometry of the solid is 1 AB 2 AB 3 A B 4 A B

The Enthalpy of neutralization of acetic acid and sodium hydroxide is 55 4 kJ What is the enthalpy ionisation of acetic acid 1 5 54 kJ 3 1 9 kJ 2 5 54 kJ 4 1 9 kJ

9 The number 0 3 g molecule is 1 4 2 NA 3 25 2 NA of electrons in oxygen atom in of Mohr s salt FeSO4 NH4 2SO4 6H O 2 42 NA 4 33 6 NA

iii 3 4 5 6 7 181 9 10 The total charge coulombs required for complete electrolysis is A 24125 B 48250 C 96500 D 193000 A student performs a titration with different burettes and finds titre values of 25 2 mL 25 25 mL and 25 0 mL The number of significant figures in the average titre value is JEE 2010 3 163 Reaction of Br with Na CO3 in aqueous solution gives sodium bromide and sodium bromate with evolution of CO gas The number of sodium bromide molecules involved in the balanced chemical JEE 2011 4 180 equation is JEE 2007 4 162 Dissolving 120 g of urea mol wt 60 in 1000 g of water gave a solution of density 1 15 g mL The JEE 2011 3 160 molarity of the solution is A 1 78 M B 2 00 M C 2 05 M D 2 22 M 29 2 w w HCI stock solution has a density of 1 25 g mL The molecular weight of HCI is 36 5 g mol The volume mL of stock solution required to prepare a 200 mL solution of 0 4 M HCl is JEE 2012 4 136 For the reaction I CIO3 H SO4C HSO4 1 The correct statement s in the balanced equation is are A Stoichiometric coefficient of HSO is 6 B lodide is oxidized C Sulphur is reduced D H O is one of the products JEE Advanced 2014 3 120 A compound H X with molar weight of 80 g is dissolved in a solvent having density of 0 4 g ml Assuming no change in volume upon dissolution the molality of a 3 2 molar solution is JEE Advanced 2014 3 120 and solvent The mole fraction of a solute in a solution is 0 1 At 298 K molarity of this solution is the same as its molality Density of this solution at 298 K is 2 0 g cm The ratio of the molecular weights of the solute MWsolute MW solvent JEE Advanced 2016 3 124 is The order of the oxidation state of the phosphorus atom in H PO2 H3PO4 H3PO3 and H4P O6 is JEE Advanced 2017 3 122 B H3PO4 H4P206 H3PO3 H PO2 D H3PO3 H PO2 H3PO4 H P O6 A H3PO4 H3PO2 H3PO3 H4P2O6 C H PO H3PO3 H4P2O6 H3PO4 PART II JEE MAIN AIEEE PROBLEMS PREVIOUS YEARS m are present in

Which of the following is are correct A At 75 C ionic product of water is more than 1 0 10 4 M B At 25 C degree of dissociation of water is 1 8 x 10 7 C At 75 C water is acidic D PH pOH 14 at all temperature

Thiosulphate reacts differently with iodine and bromine in the reactions given below 2S O3 1 S 0 21 2 S O3 2Br 5H O2SO2 2Br 10H Which of the following statements justifies the above dual behaviour of thiosulphate 201 a b Bromine is a stronger oxidant than iodine Bromine is a weaker oxidant than iodine c Thiosulphate undergoes oxidation by bromine and reduction by iodine in these reactions Bromine undergoes oxidation and iodine undergoes reduction in these reactions d

Two elements X Atomic weight 75 and Y Atomic weight 16 combine to give a compound having 75 8 of X The empirical formula of compound is 1 XY 2 X Y 3 X Y 4 X Y

Multiple Choice Questions 1 The squirrel wore a a tail c a coat FIN b a wig d a sm

A first order reaction is carried out with an initial concentration of 10 mol per litre and 80 of the reactant changes into the product Now if the s reaction is carried out with an initial concentration of 5 mol per litre for the same period the percentage of the reactant changing to the product is 2 80 1 40 3 160 4 Cannot be calculated

Pro A compound contains 4 07 hydrogen 24 27 carbon and 71 65 chlorine Its molar mass is 98 96 g What are its empirical and molecular formulas

What can be achieved can be prevented a Drinking boiled and filtered water b Avoiding smoking and alcoholism c Regular balanced diet and exercise d Proper checking of blood before blood donation

12 An ideal gas is taken through the cycle 19 Heat capacity Cy of an ideal gas is X K mole K To rise its temperature from298 K to 318 K heat to be supplied per 10g gas will be B C A as shown in figure If net A heat supplied to the gas in the VA in KJ MW 16 cycle is5J the 1 16X work done by the 3 32 X gas in the process 1 27K Cal 3 33K Cal C N 5 JE 15 For an ideal gas av 2 10J E H and heat capacities AH 13 Latent heat of vapourisation of a liquid at 500 K and latm pressure is 10K Cal mole What is the change is internal energy when 3 mole n liquid vapourised at the same temperature 7 HINT AHAE AnRT 2 7K Cal 4 25K Cal 202 3 15J 11 10 P N m 4 20J 14 The molar heat capacity of water at constant pressure C is 75 JK mol When 1 OKJ of heat is supplied to 100g of water which is free to expand the increase in temperature of water is 1 1 2K 2 2 4K 3 4 8K 4 6 6K is 22 Which one of the following is not a state function DAH 2 AS 3 S 4 W 23 A gas absorbs 250 J of heat and expands from 1 litre EDUCATION Me to 10 litre at constant temperature against 1 zero 4 AH 16 For a gas having molar mass M specific heat at constant pressure can be given as M 1 YR M Y 1 17 Molar heat capacity of water in equilibrium Y 3 RM R Y 1 with the ice at constant pressure is 4 YRM Y I 1 Zero 3 40 45 KJK mol 18 Heat capacity of water is 18 cal degree mol The quantity of heat needed to rise tempera ture of 18g water by 0 2 C is X cal Then amount of CH4 to be burnt to produce X cal heat is 2 Infinity 0 4 5 48 JK mol 2 6 25X an 12 20 Change in enthalpy when 11 2 dm of He at NTP is heated in a cylinder to 100 C is assume ideal behaviour Hint AH nCAT for mono atomic gas Cp 5 2R 1 623 5J 3 1227J CH 20 CO 2H O AH 200K Cal 1 1 8 x 10 mol 2 3 6 x 105 mol 3 0 0288 g 4 0 288 mg 21 In which of the following conditions increase in internal energy AE 0 is maximum 7 1 q 500J W 200J 2 q 400J W 200 4 q 400J W 1001 3 q 500J W 200J 2 1039 25J 4 520J external pressure of 0 5 atm The values of q w and AE will be respectively 1 250J 455J and 710J 2 250J 455J and 205J 3 2501 455J and 205J 4 250J 455J and 205J Heat of formation and combustion 24 Heat of combustion of C H is 337 K Cal If 5 6 lit O is used at STP in the combustion heat liberated is K Cal 1 28 08 3 42 06 1 650g 3 327g 2 14 04 4 56 16 25 Human body requires 2370 K Cal of energy daily The heat of combustion of glucose is 790 K cal mole The amount of glucose required for daily consumption is 2 540 4 490 5

Which of the followng process is an example of homogeneous catalysis 1 Haber s process 2 Deacon s process 3 Lead chamber process 4 Bosch process

5 One of the characteristic properties of non metals is that they a are reducing agents b form basic oxides c form cations by electron gain d are electronegative 1993 more polar

2 CH C CH A B a 1 1 H In compounds A and B inductive effect of phenyl group is b 1 1 c 1 1 d 1 1

Liquid benzene CH burns in oxygen according to 2CH 1 150 g 12CO g 6H O g How many litres of O at STP are needed to complete the combustion of 39 g of liquid benzene 1 74 L 2 11 2 L 3 22 4 L 84 L LA

5 In a reversible reaction K K P 40 K Cal The product will be obtained in less amount on 1 Increasing both pressure temperature 2 Decreasing both pressure temperature 3 Decreasing pressure increasing temperature 4 Increasing pressure decreasing temperature

with dilution in case of strong and weak electrolyte 2 HS 2013 3 Define molar conductivity of an electrolytic solution How does molar conductivity vary wit concentration for weak electrolyte 2 HS 2015

3 Which of the following compound will not show optical isomerism 1 3 X CH CH CH CH 2 CH CH 4 all of these

in the mixture of NaHCO3 and Na CO volume of a given HCl required is x ml with phenolphthalein indicator and further y ml required with methyl orange indicator Hence volume of HCl for complete reaction of NaHCO is D y x B y A 2x X N

H H K4 The Qvalue is 4 0 MeV and so this nuclear reaction liberates about 1 MeV per nucleon roughly the same as the fission reaction This reaction can be performed in the laboratory by accelerating a beam of deuterons on to a deuterium target In order to observe the reaction we must get the incident and target deuterons clased enough that the nuclear force can produce the reaction that is we must overcome the mutual Coulomb repulsion of the two particles We can estimate this Coulomb repulsion by calculating the electrostatic repulsion of two deuterons when they are just touching The radius of a deuteron is about 1 5 fm and the electrostatic potential energy of the two charges separated by about 3 fm is about 0 5 MeV We can produce such a beam of deuterons in many of the accelerators available in nuclear physics laboratories The beam currents of such accelerators are typically of the order of microamperes If every particle in the beam produced a reaction hardly a reasonable assumption the total power produced would be 4W An output of 4W assuming we could extract every bit of the energy liberated in the reaction which appears as the kinetic energies of the products H and H hardly makes this device a useful power source According to the passage the fusion reaction initiated by accelerators in laboratories is not useful source of energy because A Q value per reaction is very low C Radioactive daughter nuclei are produced B The energy losses are high D The power output is low For initiating the reaction the energy of incident deuterons should be of the order of B 1 0 MeV A 0 5 MeV C 4 0 MeV D 4 5 MeV What is the mass of tritium atom if mass of hydrogen atom 1 0078 amu Mass of Deuterium atom 2 0141 amu 931 5 MeV c A 3 0161 amu B 3 0204 amu C 3 0247 amu D 3 0118 amu

576 Mixture of acetone and methyl alcohol car separated by 1 Simple distillation 2 Fractional distillation 3 Sublimation

7 moles of a tetra atomic non linear gas A at 10 atm and T K are mixed with 6 moles of another gas B at K and 5 atm in a closed rigid vessel without energy transfer with 3 5T surroundings If final temperature of mixture was K then gas B is Assuming all modes of 6 energy are active a monoatomic b diatomic c triatomic d tetra atomic

97 of chloride ion in What is the molar concentration the solution obtained by mixing 300 mL of 3 0M NaCl and 200 mL of 4 0 M solution of BaCl 1 5 0 M 2 1 8 M 3 1 6 M 4 None of these

Explain the deviation in ionisation enthalpy of some elements from the general trend by using figure Ionisation enthalpy AH kJ mol 2500 2000 1500 1000 500 899 Be 520 Li 1402 N 2080 Ne 1681 F 3 0 1314 C 1086 B 801 T 1 2 3 4 5 6 7 8 9 10 Atomic number

Human environment is formed by human beings An ecosystem is a distinct zone within the biosphere formed by the interaction of all living organism each other and with the physical environment in which they live Human beings interact with the environment and modify it according to their needs Time to Writer A Tick the correct answer 1 The surrounding of a living thing in which it exists is termed as its a lithosphere b environment c hydrosphere 2 Ecology is the study of organisms and the environment they live in a Ecology b Abiotic environment c Biotic environment d Ecosystem 3 The mixture of gases is commonly known as a solar radiation b air c humidity 4 Which gas is essential to maintain the fertility of the soil b Carbon dioxide c Methane 2 3 4 d biosphere d none of these d Nitrogen a Oxygen 3 Fill in the blanks 1 Environment is our basic life support system Nitrogen is required to maintain the fertility of the soil Ozone blocks the harmful ultraviolet rays of the sun Ecologists study specific areas of biological activity called cosustoms

52 4 g of hydrogen are ignited with 4 g of oxygen The weight of water formed is 1 0 5 g 3 4 5 g t 2 3 5 g 4 2 5 g

IS dro number e magnitude of e electron coulomb mulomb lomb mb 27 WIN NA AVA XN N ples of electrons is Eq 9 q DXF ON 4 ular mass of H SO4 in gram is a 98 g b 98 X 1 66 X 10 24 g c 98 001 g b 98 001 X 1 66 X 10 24 Q8 Which one is more heavier 98 an Q9 The new N a 3 g atom of nitrogen b 1 5 g molecules of Oxygen 5 mol o 1 5 c 45 4 L of hydrogen at STP d 1 mole of chlorine 3 mol N na N

a 2 85 x 10 51 Which of the hydrated species can exist I H502 II H O Select alternate from a II only IV H 0 III H 30 d I II III and IV c I II and IV Which one s when dissolved in water will produce an ac b I and II

verage The total number of electrons present in 1 6 gm of methane is a 6 02 1023 b 6 02 x 1022 of methane c 6 02 x 10 1

All India Aakash 48 The equivalent weight of NaH PO4 in the reaction NaH PO KOH NaKHPO4 H O is Given Atomic masses Na 23 K 39 P 31 1 158 2 60 3 97 4 120

23 A gas absorbs a photon of 355 nm and emits at two wavelengths It one of the emissions is at 680 nm the other is at 2011 1 743 Ans 2 518 3 1035 4 325 nm

Within each series properties of the elements are quite similar It is very difficult to separate them from a mixture

20 Which is expected to show paramagnetism b SO d SiO a ClO c CO 200

How many grams of concentrated nitric acid soluta should be used to prepare 250 mL of 2 0 M HNC The concentrated acid is 70 HNO a 70 0 g conc HNO3 b 54 0 g conc HNO c 45 0 g conc HNO d 90 0 g conc HNO

4 litres of the solution Calculate the mole percentage of CH OH and H O respectively in 60 by mass aqueous solution of CH C 1 45 8 54 2 2 54 2 45 8 3 50 50 4 60 40

grams of lead were in the paint sample Atomic mass of Pb 207 Catums of Calculate the following quantities Molar mass of oxygen gas if 64 g of oxygen in 22 4 L vessel exerts a pressure of 2 atm at 0 C Average molar mass of 20 gm mixture of CH g and He g in 11 2 L vessel exerts a pressure of

What amount of substance containing 60 NaCl 37 KCI should be weighed out for analysis so that after the action of 25 ml of 0 1N AgNO solution excess of Ag is back titrated with 5 ml of NH SCN solution Given that 1 ml of NH SCN 1 1 ml of AgNO AgNO NH SCN AgSCN NH NO

Which of the following does not represent redox reactions 2 2OH CrO2 H O A Cr O72 B SO2 21 2H 1 SO H O C 2Ca OH 2Cl 2 Ca CIO 2 CaCl 2H O D Cu O NO3 H Cu NO H O

Which salt can furnish H in its aqueous solution b Na HPO 3 a NaH PO2 c Na HPO 4 d All of these

218 Sodium chloride is added to the solution after Saponification to cause the b precipitation of soap d none of these a hydrolysis of soap c sedimentation of soap Q19 Number of oxygen atoms in 8g of ozone is 6 02 1023 2 Q20 a 6 02 1023 b a Ni and Cr c b Cu and Cr 6 02 1023 3 d Stainless steel is very useful alloy in everyday life In this alloy the iron is mixed with 6 02 1023 6 c Ni and Cu d Cu and An

Edge length of a cubic unit cell is 400 pm Its face diagonal would be 1 600 pm 2 200 pm 3 566 pm 4 692 pm Its odge

5 The pair of compounds which cannot exist in solutic is a NaHCO3 and NaOH b Na2SO3 and NaHCO3 c Na CO3 and NaOH d NaHCO and NaCl

A sample of water has its hardness due to only CaSO4 When this water is passed through on anion exchange resin SO4 ions are replaced by OH A 25 0 mL sample of water so treated requires 21 58 mL of 10 3 M H SO4 for its titration What is the hardness of water expressed in terms of CaCO3 in ppm Assume density of water 10g m

76 The first Lyman transition in the hydrogen spectrum has AE 10 2 eV The same energy change is observed in the second Balmer transition of 80 1 Li 3 He 2 Li 4 Be

52 The chloride of metal has the formula MCI The formula of its phosphate is 1 M PO4 3 3 M PO 2 MPO4 4 M3 PO4 2

The increasing order of atomic size of Li Be B and Ne is