General Questions and Answers

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

Jane has developed an equation relating cholesterol levels to hours of exercise hours in the sunlight and protein food consumed Bill has an idea that when there are many rainy days cholesterol levels are low and Tom has found that more days in the gym and dietary fat consumed relate to cholesterol levels but he hasn t quantified his data Who is proposing a hypothesis who a theory and who a law O Jane and Bill hypotheses Tom a theory O Bill a law Jane a theory and Tom a hypothesis O Jane a law Tom a theory and Bill a hypothesis Jane a theory Tom a hypothesis and Bill a law

N At 298 K in a constant volume calorimeter 0 01 mole of TNT was detonated when 8180 cals of heat was released Each mole of TNT gives 6 moles of gaseous products on detonation What is AH mole of TNT exploded H

Since right hand side does not contain concentration term hence time taken for the completion of any fraction first order reaction is independent of initial concentration of the reactant Example 13 A first order reaction is 50 complete in 100 minutes How long will it take for 90 completion

Problem 8 10 Permanganate VII ion MnO4 in basic solution oxidises iodide ion I to produce molecular iodine 1 and manganese IV oxide MnO Write a balanced ionic equation to represent this redox reaction

6 Why is it important to neutralize the basic solution the one that contains the acid unknown to pH 3 Instead of just pH 7 Why is the acidic solution containing the basic unknown neutralized to pH 11 or greater To answer this question you will need to discuss pka s of the compounds

78 What is pH of the resulting solution when 100 m of 0 1 M NaOH is mixed with 100 ml of 0 1 M CH COOH PK for CH COOH 4 76 1 8 73 3 8 58 2 7 38 4 5 27

Which of the following compounds can be used to obtain free nitrogen A NH4NO B HNO2 C HNO3 D Ba3N Solution A NH4NO ammonium nitriteis the only convenient compound that can be used to obtain fre nitrogen even in laboratories NH Cl aq NaNO aq NH4NO aq NaCl aq By heating ammonium nitrite A NH NO g No a 2H O 1

Concentrated aqueous sulphuric acid is 98 H SO4 by mass and has a density of 1 80 gmL 1 Volume of acid required to make one litre of 0 1 M H SO4 solution is 116 65 mL 2 22 20 mL 3 4 O 5 55 mL O 11 10 mL

How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2 M HNO3 The concentrated acid is 70 w w HNO3 NEET 2013 1 90 0 g conc HNO3 2 70 0 g conc HNO3 3 54 0 g conc HNO3 4 45 0 g conc HNO3 21

20 Assertion Semiconductors are solids with conductivities in the intermediate range from 10 6 104 ohm 1m 1 Reason Intermediate conductivity in semiconductor is due to partially filled valence band O C

bo a IU c 20 14 g 001 21 zaobusd d 40 bsd to 101 70 A compound possesses molecular mass is 80 1 6 a 200 c 155 8 sulphur by mass The b 400 d 355 1 Equivalent weight of I in the reaction 7 1 5Cl 6H O 2HIO3 10HC1 is a M c M 5 b M 2 d M 10

WORKED OUT EXA EXAMPLE 19 Calculate AH for the reaction CH g 4F g CF g 4HF g Given that the enthalpies of formation of CH CF and HF are 75 kJ 680 kJ and 269 kJ respectively SOLUTION YAH Reactants

7 The edge length of a unit cell of a metal having molecular mass 75 g mol is 5A which crystallises in a cubic lattice If the density is 2 g cc then find the radius of metal atom 8 a State Rault s law and Show that relative lowering in vapour pressure ids equal to mole

54 If one atom of an element A weighs 6 644 x 10 23 g the number of gram atoms in 20 kg of it is b 20 01 x S 10 d 2000 a 500 c 1000 TO JE 11 55 The volume occupied by 1 mole atom of a diatomic gas STP is a 22 4 L b 11 2 L 5501 0 8 6

More Than One Option Correct ch of the following changes is are observed when ore is heated for calcinations A PbSO4 PbO PbSO4 B PbCO3 PbO C PbS D Fe O3 3H O Fe O3 hich of the following is a halide ore

Identify the incorrect statement among following 1 CH CH 10 CH NH is not a surfactant 2 Surfactants are positively adsorbed at interfaces between two phases and they lower interfacial tension 3 Quaternary ammonium salts cannot act as surfactants 4 Surfactants can be neutral positive or negative in charge

8 Which of the following statements is not true 1P 1 Paramagnetic substances are weakly attracted by magnetic field O ii Ferromagnetic substances cannot be magnetised permanently O iii The domains in antiferromagnetic substances are oppositely oriented with respect to each other iv Pairing of electrons cancels their magnetic moment in the diamagnetic substa

6 Which of the following point defects are shown by AgBr s crystals A Schottky defect B Frenkel defect C Metal excess defect D Metal deficiency defect 1 A and B ii C and D O iii A and C iv B and D

8 x g of NaCl is added into 100 ml of H O to prepare y molar solution 10 ml of its sample taken in separate test tube The molarity of the sample taken in test tube will be 1 10y M 2 W 2 5y MomeH 8 4 Oy M

d composition 2 An element crystallises in fcc lattice having edge length 350 pm Maximum radius of the atom which can be placed in the interstitial site without distorting the structure is a 58 55 pm b 117 pm d 83 pm c 51 23 pm

c 2 648 g d 5 295 g 1 Which of the following contains the greatest number atoms a 1 0 g of butane C H 0 b 1 0 g of nitrogen N c 1 0 g of silver Ag d 1 0 g of water H O

the unit cell of a mineral has cubic close packed ccp array of oxygen atoms with m fraction of octahedr moles occupied by aluminium ions and n fraction of tetrahedral holes occupied by magnesium ions m and JEE Adv 2015 Paper 1 espectively are 1 1 28 1 1 A C B 1 D 4 1 1 48

4 KBr KlFe A metal carbonate 0 5 kg gives 0 28 kg of its oxide on heating Hence the equivalent weight of metal is 1 20 g eq 2 40 g eq 3 25 g eq 4 30 g eq

the same orifice if CO was kept under the same conditions 7 78 hrs Determine the percentage of a gas mixture CH4 H2 CO2 if after the combustion of 15 mL o it with 85 mL of air the volume reduced to 83 2 mL and the total contents of CO in mixture was found to 10 8 mL H 28 CH4 35 CO2 37

If the amount of dissociation is 0 5 the value of K for the reaction N O NO NO will be 3 1 equal to the pressure of the system 2 3 3 8 3 L of the pressure of the system of the pressure of the system of the pressure of the system

Instructions Look at the example of methane in the chart below Notice how the carbon atom in methane forms four single covalent bonds with hydrogen atoms It s molecular formula is CH Next fill in the missing molecular formulas structures names and uses in the chart below Refer to pages 674 676 in your textbook and the following website for additional help https hzorganichemistry wordpress com uses of alkene The of Akm Horganichemistry World Press 16 June 2011 Web 15 Dec 2016 Molecular Formula CHA C H HICI Structure HIC H C H HIC HIC Name H H Methane Ethane SUMMER SES Propane Uses Pentane Gas used for cooking Lighter and camping fuel Use in petrol Used in petrol

8 The mass of carbon anode consumed giving only carbon dioxide in the production of 270 kg of aluminium metal from bauxite by the Hall process is Atomic Mass Al 27 1 270 kg 3 90 kg 2 540 kg 4 180 kg R

e poin group 101 101 sy y grou If C5 C and Oy are the generators of a point group write down the point group and give an example of a molecule with the structure 2 NN F 1 11

70 For a 1st order reaction A Product the initial concentration of A is 0 1 M and after 40 minute it becomes 0 025 M The rate of the reaction at reactant concentration 0 01 M is A 3 47x10 M min B 3 47x10 M min C 1 735x10 Mmin D 1 735x10 M min

roblem 7 In order to find the strength of a sample of sulphuric acid 10 g were diluted with ter and a piece of marble weighing 7 g placed in it When all action had ceased the marble was removed shed dried and was found to weigh 2 2 g What was the percentage strength of sulphuric acid Solution Mass of macht

c The enthalpy of hydrogenation of cyclohexene is 119 5 kJ mol 1 If resonance energy of benzene is 150 4 kJ mol its enthalpy of hydrogenation would be a 208 1 kJ mol 1 c 358 5 kJ mol 1 2006 b 269 9 kJ mol 1 d 508 9 kJ mol 1

311 On the basis of the following E values the strongest oxidizing agent is Fe CN Fe CN e 1 Fe2 Fe e 1 1 Fe CN 1 3 Fe E 0 35 V E 0 77 V AIPMT Prelims 2008 2 Fe CN 4 Fe

Which of the following represents the equivalent conductance at infinite dilution of Al SO Given that A A13 and Aso2 are the equivalent conductances at infinite dilution of the respective ions 2010 a A A13 A 10 so b 2A 3Aso c A Aso 4 34 1 2 6 A 3 A x

7 In which of the given reactions AH AU 1 Combustion of gaseous isopentane at 25 C 2 Hydrogenation of gaseous isobutylene 3 Reduction of ZnO by coke 4 Formation of HI g from H g and 1 g

The two equilibria ABA B and AB BAB are simultaneously maintained in a solution with equilibrium constants K and K respectively If A and AB are y and x respectively under equilibrium produced by adding the substance AB to the solvents then K K is equal to A skipped B C v x y x y y x y G

1 3 77 6 8 8 The value of gas constant R is 8 314 X Here X represents 1 Litre atm K mol 2 Cal mol K 1 3 J K mol 1 4 None of the above 2

The initial rate of hydrolysis of an ester using 1 M HA as catalyst is found to be 0 001 times of the reaction rate by using 1 M HCI In a separate experiment pH of 1 M solution of NaA after hydrolysis is found to be x Report the value of 3x to the nearest integer Assume the reaction is first order w r t catalyst

Aqueous solution of which of the followin compounds is the best conductor of electri current Re AIPMT 2015 1 Ammonia NH3 2 Fructose C6H 2O6 12 3 Acetic acid C H O 4 2 4 Hydrochloric acid HCI

The energy absorbed by each molecule A2 of a substance is 4 4 10 19 Jand both energy per molecule is 4 0 x 10 19 J The kinetic energy of the molecule per atom will be O2 0 10 20 J 22 10 19 J 020 10 19 J 4 0 10 20 J

h Molar mass of Cholesterol if 0 00105 mol has a mass of 0 525 g i Mass in grams of 3 102 molecules of Aspirin C H O j Molar mass of an element if mass of 1 atom is 12 10 24 g k Number of SO ions in 19 6 g Cr SO4 3 1 Number of Ca ions in 6 2 g Ca PO Themis

c 30 d 40 4 Find the age of an ancient Egyptian wooden article in years from the given information i Activity of 1 g of carbon obtained from ancient wooden article 7 counts min g ii Activity of 1 g carbon obtained from fresh wooden sample 15 4 counts per min g iii Percentage increase in level of C 4 due to nuclear explosions in past 100 years is 10 iv t 2 of 4C 5770 years m

a 8 16 1 c 16 1 2 b 16 8 1 Tom 9200 d 8 1 2 2014 di to ston 2 g 1 When 22 4 litres of H2 g is mixed with 11 2 litres of Cl2g each at S T P the moles of HCl formed is equal to a 1 mol of HCl g b 2 mol of HCl g c 0 5 mol of HCl d 1 5 mol of HCl g g 2014 12 1 0 g of magnesium is burnt with 0 56 g O in a closed vessel Which reactant is left in excess and how much

A student takes copper aluminium iron and zinc metals separately in four test tubes labelled as I II III and IV respectively He adds 10 mL of freshly prepared ferrous sulphate solution to each test tube and observes the colour of the metal residue in each case He would observe a grey residue in the test tubes 1 II III IV Q a I and II b I and III c II and III I and IV Cu Al Fe Zn the colutions in heaker I II III and IV After

X rays of Cuk wavelength 154 pm are diffracted by a set of atomic planes in a crystal in the following manner The separation of the layers in the crystals is 404 pm Find the angle a along which the first order reflection will occur a 79 b 45 V c 11 d None of the above

3 i Write down the generators point groups and the respective group elements to which the following species belong any four

f the door of a refrigerator kept in a room is opened the room will a cools down b becomes hot c It is neither hot nor cold d The change in temperature depends on the initial temperature of the room

Question 43 Assertion Following is a balanced chemical equation for the reaction of magnesium and hot water 2Mg 2H O 2Mg OH 2 H2 Reason The law of conservation of mass holds good for a chemical reaction For the above two statements given one labelled assertion and the other labelled reason Select the correct answer to these questions from the course a b c and d as given below a Both assertion and reason are true and reason is the correct explanation of the assertion b Both assertion and reason are true but reason is not the correct explanation of the assertion c Assert ion is true but reason is false d Assertion is falls but reason is true

ii Construct the matrix for reflection of a point x x z through a plane which contains the Z axis and is at an angle 45 to the X and Y axes 1 5

Analysis for detection of alcohol in blood uses the concept of redox titrations according to reaction unbalanced C H5OH Cr O CO H O Cr 7 In one such experiment 10 ml of 0 05 M K Cr O7 is required to completely neutralise 10 gm sample of blood What is the percentage by weight of alcohol in blood 1 1 15 3 0 115 2 0 0115 4 11 5