General Questions and Answers

At 300 K and 1 atm 15 mL of a gaseous requires 375 mL air containing 20 O by volume for complete combustion After combustion the gases occupy 330 mL Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure the formula of the hydrocarbon is CI CIT Main 2016 d CU

1 The flux associated with a coil changes from 1 35 Wb to 0 79 Wb within s Then the charge 10 which flows in the coil if resistance of coil is 702 is 2 0 8 C 1 0 08 C 3 0 008 C 4 8 C A vessel contains 1g of oxygen at a pressure of 10 atm and a temperature of 47 C It is found that because of a leak the pressure drops to of its original value and the temperature falls to 27 C

You have a certain mass of helium gas in a rigid steel container You add the same mass of neon gas to this container Assuming that he temperature remains constant which of the following best describes what happens The volume in the container doubles The pressure in the container increases but does not double The pressure in the container drops The pressure in the container doubles

c Ke 5 During complete combustion of one mole of butane 2658 kJ of heat is released The thermo chemical reaction for above change is a 2C H g 130 g 8CO g 10H O 1 AH 2658 0 kJ mol 13 b C H g 0 g 4CO g 5H O 1 A H 10 1329 0 kJ mol 13 c C H g O g 4CO g SH O 1 AH 10 2658 0 kJ mol d C H g O g 4CO g 5H O l AH 2658 01 sell

c 6 94 kg d 16 8 kg A balanced equation for combustion of methane is given below CH 20CO1H O Which of the following statements is not correct or the basis of the above chemical equation a b c d One mole of CH reacts with 2 moles of oxygen to give one mole of CO and 2 moles of water One molecule of CH reacts with 2 molecule of oxygen to give one molecule of CO and 2 molecules of water 22 41 of methane reacts with 44 8 L of oxyge to give 44 8 L of CO and 22 4 L of water 16 g of methane reacts with 64 g of O to giv 44 g of CO and 36 g of water

At 1000 K water vapour at 1 atm has been found to be dissociated into H and O2 to the extent of 3 x 10 6 Calculate the free energy decrease of the system assuming ideal behaviour 1 AG 90 060 cal 2 AG 20 cal 3 AG 480 cal 4 AG 45760 cal

The rate constant the activation energy and the frequency factor of a chemical reaction at 25 C are 3 0 x 10 4 s 104 4 KJ mol and 6 0 x 10 4 s1 respectively The value of the rate constant as T 1 8 is A B C D 2 0 x 1018 S 1 x 10 4 S 1 6 0 x 1 infinite 3 6 x 1030 5 1 X

If bond energies of C C and C H bonds are 336 2 kJ and 416 2 kJ respectively then the value of heat of atomisation of ethane is 1 752 4 kJ mol 2 2161 kJ mol 3 2001 kJ mol

Some Basic Concepts of Chemistry gram afom 61 How many grams of CaO are required to react with 852 g of P 0 0 a 852 g b 1008 g c 85 g d 7095 g 68 The cal a

Steam distillation was carried out for an immiscible liquid P and it was observed that 100 ml of the distillate contained 28 ml of P The boiling point o the distillation was found to be 95 C at a pressure of 750 torr At 95 C assum that the vapor pressure exerted by water is 700 torr If the density of liquid P is 2 5 g ml then select the correct statements Vapor pressure of pure P at 95 C is 50 torr Molar mass of liquid P is 200 g mol Molar mass of the liquid P is 280 g mol Mass percent of P in the distillate is 49 3 approx

Thermal decomposition of dibrom coinic acid DBSA taking place according to the following equation obeys first order kinetics CH Br COOH a c CH Br COOH CBrCOOH The progress of reaction may be followed by means of alkali titration of the solution definite volume of reaction mixture at various time intervals If To and T be the ml of alkali solution at zero time and at any time t respectively and a and a x be the concentrations of DBSA at zero time and at any time t respectively then the value of a is T 3T 2T CHCOOH To T T b HBr d T FR T T 2T T a X

3 262 5 4 41 2 1 524 1 2 41 2 Which of the following is not an actinoid 1 Curium Z 96 3 Uranium Z 92 A chloride dissolves appreciable in cold water When placed on platinum wire in Bunsen flam distinctive colour is noticed Then the cation is 1 Mg 2 Ba 3 Ag 4 Ca In the chemical reaction 2 Californium Z 98 4 Terbium Z 65

16 If both oxygen and helium gases are at the same temperature the rate of diffusion of O is very close to a 4 times that of He b 2 times that of He c 0 35 times that of He d 8 times that of He

are prepared using MgSO4 and MgSO4 7H O with water In first case 91 kJ heat evolved while in 2nd case 13 kJ heat is absorbed enthalpy of hydration of MgSO4 will be Options 78 kJ mole 1 78 kJ mole 1 104 kJ mole 1

c 606K d 273K 43 The critical temperatures of O N H and CO are 154 3 K 126 K 33 2 K and 304 K The extent of adsorption on tungsten may be highest in case of b N d CO a H c 0

b 6 023x10 15 x 10 2 c 7 5 x 102 15 x 10 2 d 15 x 1022 7 5 x 10 50 Total number of atoms present in 34 g of NH is a 4x10 b 48x10 c 2 x 10 d 48 x 1023 51 What will be the mass of 100 atoms of hydrogen

Which of the following statements is invalid 1 The more stable the carbocation the faster it is formed 2 Propyl cation changes to more stable isopropyl carbocation by 1 2 shift of a hydrogen 3 Isopropyl chloride reacts with sodium ethoxide to form 1 ethoxypropane 4 Propyl halides reacts with sodium ethoxide to form 1 ethoxypropane

100 ml of an ideal gas is heated in an open vesse from 300 K to 400 K The volume of gas that wil remain in the vessel is 1 133 ml 3 33 ml 2 100 ml aldellou 4 67 ml

kcal mole and 310 0 kcal mole 1 respectively then Options Ethane is better welding gas having more magnitude of AcHo Ethyne is better welding gas having more value of AcH Ethyne is better welding gas having more magnitude of AcH0 unit weight Fthane is better welding gas as here

d A iv B iii 46 The number of oxygen atoms present in 1 mole of oxalic acid dihydrate is a 6x102 c 7 22 x 10 b 6 022 x 10 d 36 13 x 10 3

d atomic masses cannot be weighed accurately 39 Oxygen occurs in nature as a mixture of isotopes OO and O having atomic masses of 15 995 u 16 999 u and 17 999 u and relative abundance of 99 763 0 037 and 0 200 respectively What is the average atomic mass of oxygen a 15 999 u b c 17 999 u d 16 999 u 18 999 u

57 What will be the weight of CO having the same number of oxygen atoms as present in 22 g of CO a 28 g c 44 g b 22 g d 72 g 58 Match the mass of elements given in column I with

0 02N A A 59 Which is mismatched regarding the position of the element as given below a X Z 89 f block 6th period b Y Z 100 f block 7th period c Z Z 115 d block 7th period d Both a c 64 W alu a A C F 65 Ger peri not a N c N

Que 15 If the nitrogen atom had electronic configuration 1s7 it would have energy lower than that of the normal ground state configuration 1s2 2s2 2p3 because the electrons would be closer to the nucleus yet 1s7 is not observed because it violates Heisenberg uncertainty principle Hund s rule Pauli exclusion principle

a 375 K c 546 K b 750 K d 408 K 36 If the density of a gas A is 1 5 times that of B then molecular mass of A is M The molecular mass of B will be a 1 5M b M 15 d M 3 c 3M

6 In a mixture of gases the volume content of a gas is 0 06 at STP Calculate the number of molecules of the gas in 1 L of the mixture a 1 613 x 102 c 1 61 x 1027 b d 6 023 x 1023 1 61 x 10 9

Rearrange the following I to IV in the order of increasing masses I 0 5 mole of 03 II 0 5 gm atom of oxygen III 3 011 x 1023 molecules of O IV 5 6 litre of CO at STP A II IV III I C IV II III I B II I IV III D I II III IV

3 The diagram shows the thermometer before and after adding the ammonium chloride in C C C 10 10 20 20 Fig 4 40 40 M i Record each of the temperatures and determine the fall in temperature Temperature before adding the ammonium chloride Temperature after adding the ammonium chloride Fall in temperature Covert the fall in temperature it to Fahrenheit m 50

Fig 1 i State three processes by which the dish and its contents could lose heat to the surroundings 2 Here are some statements about energy Select words from the following list and complete the statements I chemical electrical geothermal heat hydroelectric light movement kinetic position potential strain tidal wave a A coal fire converts energy and b When a ball falls from rest its energy into energy energy increases and its energy decreases c The source of energy in which hot rocks under the Earth s surface heat water to produce

4 Iron can be obtained by reduction of iron oxide Fe O with CO according to the reaction FeO 400 3Fe 4CO How many kg of Fe 0 should be heated with CO to get 3 kg of tron a 8 12 kg c 6 94 kg b 4 14 kg d 16 8 kg

54 1 4 moles of phosphorus trichloride are present in a sample How many atoms are there in the sample a 5 6 c 2 4 x 1023 b 34 d 3 372 x 1024 CH

48 Which of the following gases will have least volume if 10 g of each gas is taken at same temperature and pressure a CO c CH b N d HG molec es and toms

c 19300 d 10 33 The ratio of masses of hydrogen and magnesium deposited by the same amount of electricity from H SO4 and MgSO4 in aqueous solution are a 1 8 b 1 12 c 1 16 d none of these The cell reaction for the given cell is spontaneous if

One gram of silver gets distributed between 10 cm of molten zinc and 100 cm of molten lead at 800 C The percentage of silver in the zinc layer is approximately Given Partition coefficient of Ag in Zn and Pb is 300 A 89 B 91 C 97 D 94 Owl of athul oploohol to formethyl acetate The density of acid and alcohol are

Sir in Cr NH3 6 how number of unpaired electron is 3 As Cr have 3d configuration but due to strong ligand it should be paired and number of unpaired electron should be 1 T

The vapour pressure of water at 293 K is 17 51 mm The lowering of vapour pressure of sugar is 0 0614 mm Calculate a The relative lowering of vapour pressure b The vapour pressure of the solution C The mole fraction of water

4 The owner of a small factory suggests installing a wind turbine to generate some of the electricity needed by the factory Discuss three of the factors that the owner will need to consider when deciding whether to install a wind turbine

c 22 4 L d 4 L 5 If V is the volume of a given mass of gas at 273 K at a constant pressure then according to Charle s law the volume at 10 C will be a 11V b V 10 273 c V 10 273 d 283 273 Vo

13 In which one of the following does the given amount of chlorine gas exert the least pressure in a vessel of capacity 1 dm at 273 K a 8 0355 g b 0 071 g c 6 023 1021 molecules d 0 02 mol

5 The radii of two of first six Bohr s orbits of H atom are in the ratio 4 9 The energy difference between them may be a Either 12 09 eV or 3 4 eV b Either 2 55 eV or 10 2 eV c Either 1 89 eV or 0 49 eV d 1 89 eV only

Express your answer as signed integers separated by a comma View Available Hint s the oxidation states of V O 2 1 5 Your submission doesn t have the correct number of answers Answ No credit lost Try again

A solution is made by adding 36 7 mL of pure alcohol to enough distilled water t make 75 0 mL of solution What is the percent v v of isopropyl alcohol in the sample a 48 9 c 95 8 b 51 1 d 4 2 e 50 0

A student dissolved 0 515 mol of magnesium chloride in enough water to make 225 mL of solution What is the molar concentration of the magnesium chloride in solution e 0 44 mol L a 2 29 mol L b 0 00229 mol L c 0 00458 mol L d 4 58 mol L

Reason At any gas oc 9 Assertion The number of significant figures in 1502 cm is two Reason In 1502cm zero may or may not have any significance

5 A wagon loaded with iron blocks is pushed up an inclined plane to its highest point The total mass of the wagon is 50 kg and the height of the topmost point from the ground is 10 meters What is the total potential energy of the wagon at the top Show formulae and working part clearly

5 Which of the following factors decreases the overpotential a increase in thermionic work function c increase in current density S What is the condition under which O motal inn i b smooth surface d increase in temperature 10 hydron

The concentration of Hg2 is controlled by equilibrium with a mineral hase The water in the sediments is characterized by pH 7 3 PH2S 10 5 0 bar Pco2 10 22 bar and CI 10 3 2 M a Which mercury Hg2 solid will control the solubility of Hg2 Use the appropriate Hg2 solid species from the following list and Show your calculations Hg OH s Hg 2 OH HgO s H O Hg 2 OH Hg CN s Hg 2 CN HgCO3 s Hg2 CO3 HgS s Hg S Kso 10 25 40 K 10 25 55 Kso 10 39 28 Kso 10 22 52 Kso 10 52 01

16 mL of a hydrocarbon gas was exploded with exc ess of oxygen On cooling the volume of the resulti ng gaseous mixture was reduced by 48 mL When K OH was added there was a further decrease of 48 mL in the volume Find the molecular formula of th

What can happen if too much solvent is added to the sample A Nothing it is fine to add excess solvent B The solute might remain dissolved C The solution will have to be cooled much quicker D Activated charcoal can dissolve in it

Show how to carry out the transformation in the highest yield possible Select the appropriate reagents and draw the correct organic product at each step Identify reagent 1 1 Zn HCI 2 NaOH HNO3 H SO4 Br FeBr3 Identify reagent 2 HNO H SO reagent 1 product 1 HNO3 H SO4 1 Zn HC1 2 NaOH reagent 2 Draw product 1 Select Draw Rings G C Br More Erase Q2 Q