General Questions and Answers

Helium and neon is present in insulated container that is divided into two compartments at conditions given below Ne He P n T V P n T V 21 2 If wall is removed such that no work is done then select the incorrect statement about the final mixture of gas 1 Final pressure is R n T n T 2 V V n T n T 2 n n 3 y C C of final mixture is same of initial 2 Final Temperature is

d 0 477 M and 0 477 M Which has the maximum number of molecules among the following a 44 g CO c 8 g H b 48 g 03 d 64 g SO 2011 Mains 6 02 1020 molecules of urea are present in 100 mL of its solution The concentration of solution is

25 Which of the following has maximum number of atoms Atomic mass of Fe 56 u and Ag 108 u 1 28 g of carbon monoxide 2 28 g of iron metal 3 24 g of ozone

In a reaction 2HI g H g 1 g the concentration of HI decreases 0 6 M to 0 5 M in 10 minutes The average rate reaction during this interval is 0 05 M min 1 0 005 M min 1 0 01 M min 1 0 001 M min

Student A wanted to determine the IN of an unknown oil density 0 85 g mL using pyridinium tribromide as a halogenation agent The student added 0 488 g of pyridinium tribromide in 20 ml 1 v v oil solution and proceeded accordingly Student A recorded that 31 mL of 0 1 N was added for the dark brown color of the oil solution to disappear How many grams g of bromine MW Br 160 g mol reacted with the oil None of the choices O 0 49 g 0 74 g O 0 24 g 0818

stion No 21 40 Synthetic polymer may consist of A O Crystalline Regions BO Amorphous CO Both Crystalline and Amorphous DO None of these 20064590

75 4G for the decomposition of Al O3 at 500 C is 965 76 The kj mol C the Zr W 2 3 Al O 4 3 Al O The potential difference required for electrolytic reduction of Al O3 at 500 C should be at least 1 2 5 V 2 4 V 3 5 V 4 3 V wa C

Viriat is Apply what you learn about the working principles of fractional distillation to explain the separation steps of the water ethanol mixture if the boiling point of methanol is 64 C 2 Marks A process engineer decided to use the distillation process to separate a liquid mixture consists of two components the

Which ones can be used to detect systematic error A Compare your method with a known sample B Observe the result of a blank sample C Compare the results of parallel measurements using different method D Different people in different labs analyze identical samples by the same method E Different people in different labs analyze identical samples by different methods D and E A B and D B C and D A B D and E All of the choices

In the cell reaction Cu s 2Ag aq Cu2 aq 2Ag s E cell 0 46 V By doubling the concentration of Cu Ecell is A Doubled B C Half Unchanged

50802 uostion No 35 40 Addition of different types of monomers to form polymer chains AO Chain reaction polymerization BO Combination CO Disproportionation Copolymerization

A lake is stratified due to temperature differences throughout its depth but has continuous vertical mixing What would the mixing rate be if a The top 10 ft of water has a constant total carbon concentration of 2 44E 3 mol L with a 4C C ratio of 0 92 x 10 mol mol b At 100 ft the total carbon concentration is 1 93E 3 mol L with a 4C C ratio of 0 77 x 10 12 mol mol

Q26 Based on the pK values listed below and structural effects on acid strength select an acid base equilibrium that favors the LEFT side Keq 1 H O 1 7 H O 15 7 DA A H O HCl B H NO HBr C CH3CH NH CF3CH OH D CH3CH OH H S H CI 7 H O Cle NH3 Bre CH3CH 0 H 16 CF3CH O CH3CH NH CH3CH O H SO

CAREER INSTITUTE XI NCERT Unit 2 Structure of Atom XI Which of the following metals give inflammble gas with 1 fit ang ur am 3 both acid and base 1 Na and Zn 3 Mg and Be 2 Mg and Al 4 Zn and Al 1 Na 3 Mg Zn Be 2 4

30 mL of 0 2 N BaCl2 is mixed with 40 mL of 0 3 N Al2 SO4 3 How many g of BaSO4 are formed A 0 10 g 0 60 g 0 90 g D 0 70 g

isplacement of Mg by iron from MgSO4 solution 4 Alum is the name used for all double salts having the composition M SO4 M SO4 3 24H O Where M stands for Al 3 Cr 3 Fe 3 while M stands for 1 Li Cut Ag 3 Na K Rb 4 Ca 2 Mg 2 Sr 2 2 Lit NH Na 4

a When SO2 is passed through the saturated solution of H2S The following reaction occurs SO2 2H2S 2H2O 3S In this reaction Which substance is i Oxidized ii Reduced iii Oxidizing agent iv reducing agent 2 b With the help of a labelled ray diagram describe how a converging mirror can be used to obtain an enlarged upright image of an object 2

8020103 stion No 22 40 Reactions in which molecules absorbing light do not themselves re induce other molecules to react are called AO Reversible reactions BO Chain reactions CO Photochemical reactions DO Free radical reaction

ICQ 100 936 The equivalent weight of CH COOH is O A 20 B 15 c 60 0 45

in H S 504 original mixture IIT J 8 To a 25 mL H O solution excess of an acidified potassium iodide was added The iodine liberate 20 mL of 0 3 N sodium thiosulphate solution the volume strength of H O solution UT J An aqueous solution containing 0 10 g KIO weight 214 0 was treated with an excess of K The solution was acidified with HCl The li consumed 45 0 mL of thiosulphate solution to de the blue starch iodine complex Calculate the m the sodium thiosulphate solution IIT JE How many millilitres of 0 5 M H SO4 is needed t 4 IIT JE 0 5 g of copper II carbonate

Stability constant is more for the complex A Ag NH3 B C Cu NH skipped Ag CN D Co NH3 6

Jestion No 40 40 The number average molar mass M and weight average molar mas of a polymer sample are 2700 and 3148 respectively The polydispersity in PDI of the polymer is A 0171 0 3 41 614 ST

Knowing that the chemistry of lanthanoids Ln is dominated by its 3 oxidation state which of the following statements is incorrect The ionic sizes of Ln III decrease in general with increasing atomic number Ln III compounds are generally colourless Ln III hydroxides are mainly basic in character Because of the large size of the Ln III ions the bonding in its compounds is predominantly ionic in character

Consider the reaction 2A B Product When concentration of B alone was doubled the rate of reaction increased by two times and when the concentration of both A and B were doubled the rate became 4 times The unit of rate constant for this reaction is 1 L mol 1 S 1 3 mol L 1 s 1 2 Unitless 4 S 1

4 8 g of oxygen is adsorbed on 1 2 g of metal powder The volume of oxygen adsorbed per gram of the adsorbent at NTP is NCERT Pg 124 1 2 8 L 3 4 6 L 2 3 6 L 4 3 21

A compressor is an important device used in industrial plants Most industrial plants have used the compressor to supply air to the reactor or combustion unit i Explain the main function of a compressor 1 Marks

Q 51 The spectral lines of atomic hydrogen wave number is equal to the difference between the wave numbers of the following two lines of the Balmer series 486 1 and loid 410 2 nm The wavelength of that line is 10 4 cm

The separation of components in a distillation column is based on the differences in volatility and boiling point As the vapor rises the tower and contacts the liquid i Why do you think reflux is needed in a distillation column 2 Marks

On the basis of de Broglie equation the following conclusions can be drawn 1 Lighter the particle greater is its de Broglie wavelength for certain velocity ii Faster the particle moves smaller is its de Broglie wavelength iii The de Broglie wavelength is independent of the nature of the particle iv The de Broglie equation is applicable to microscopic particles such as electron proton atom molecule etc and has no significance for heavier particles The wavelength is too small in the case of heavier particles which is difficult to measure Let us apply the equation to a moving electron and a moving ball weighing 200 g or 0 2 kg both travelling with the same speed 106 m s For electron 34

acetic acid and treated with excess KI The liberate requires 11 3 mL of 0 05 M Na S O3 solution for c reduction Find out the mole ratio of Cu and C the compound Write the balanced redox reactions in the above titrations IIT JEE A 1 0 g sample of Fe O3 solid of 55 2 purity is d in acid and reduced by heating the solution with z The resultant solution is cooled and made upto 10 An aliquot of 25 0 mL of this solution requires 17 0 0167 M solution of an oxidant for titration Calc number of electrons taken up by the oxidant in the of the above titration IIT JE A 2 0 g sample of a mixture containing sodium c sodium bicarbonate and sodium sulphate is gent T

gas is treated with KOH solution Find out the compo of the gaseous mixture in terms of volume percenta IIT JEE A40g sample contained FeO FeO and inert ma It was treated with an excess of aq KI solution in medium which reduced all iron to Fe ions The res solution was diluted to 50 mL and a 10 mL sampi was taken The iodine liberated in the small samp titrated with 12 0 mL of 0 5 M Na S O3 solution iodine from another 25 mL was extracted after wh Fe ions were titrated with 16 mL of 0 25 M MnO in H SO solution Calculate the mass of two oxide IT JEE To a 25mL H O solution excess of an acidified sol indide was added The iodine liberated r

When 0 5F of electricity is passed through NaCl solution the amount of chlorine liberated is A 71g B C D skipped 142g 35 5g 17 75g Stry MY

9 Nitrate of an element of alkali metal group decomposes on heating gives brown colour gas Nitrate and brown colour gas are respectively 1 NaNO3 and NO 2 LINO3 and NO 3 KNO3 and NH3 4 NaNO3 and NO

za 2 56 Lauryl alcohol is obtained from coconut oil and is used to make detergent A solution of 5 g of Lauryl alcohol in 200 g of benzene freezes at 4 C The approximate molar mass of Lauryl alcohol will be Given K of benzene 5 1 C molal Freezing point of benzene 5 5 C Give your answer after division by 17

hysical Chemistry If equal volumes of 1 M KMnO4 and 1 M solutions are allowed to oxidise Fe II to Fe III medium then Fe II oxidised will be a More by KMnO4 c Equal in both cases b More by K Cr C d Can t be determi Sulphuryl chloride SO Cl reacts with water mixture of H SO4 and HCl Moles of NaOH re neutralise the solution formed by adding 1 mol o excess water is are 1 b 2 c 3 OH d 4 00 mL of 0 01 M KMnO oxidised 100 mL cidic medium Volume of the same KMnO4 re 4 Cel 100

45 When an object is at rest 1 Forces is required to keep it in rest state 2 No force is acting on it 3 A large number of forces may be acting on it which balance each other 4 It is in vacuum 10 32

gas behaviour calculate the mole fractions of C C H in the mixture IIT JEE 5 A 5 0 mL solution of H O liberates 0 508 g o from an acidified KI solution Calculate the stre H O solution in terms of volume strength at STI IIT JEH A 20 0 mL mixture of CO CH4 and He gases is e by an electric discharge at room temperature with of oxygen The volume contraction is found to be A further contraction of 14 0 mL occurs when the

presence of dilute involved in the reactions and calculate the me H O IIT JE 3 One gram of charcoal adsorbs 400 mL of 0 5 acid to form a mono layer and the molarity of ac reduces to 0 49 Calculate the surface area of adsorbed by each molecule of acetic acid The sur of charcoal is 3 01 10 m g IIT JE Around 20 surface sites have adsorbed N Or N gas evolved form sites and were collected at 0 and 298 K in a container of volume 2 46 cm The of surface sites is 6 023 1014 cm 2 and surfac 1000 cm Find out the number of surface sites c per molecule of N UIT JEE

7 A 0 13 g of a specimen containing MnO IS 5 iodide ions If iodine liberated requires 30 0 mL of 0 075 M solution of Na S O3 the percentage of MnO in the mineral is a 75 3 b 85 3 c 95 3 d None KA Mod at 8 The mass of K Cr O required to produce 5 0 L CO 77 C and 0 82 atm pressure from excess of oxalic acid 6 b and volume of 0 1 N NaOH required to neutralise the CO evolved respectively are 1 mens b 5 g 1 86 L d None a 7 g 2 86 Lister c 4 g 0 86 L 59 A mixture of Na C O and KHC O4 H C O4 required equal volumes of 0 2 M KMnO4 and 0 2 M NaOH separately m

500 mL of a gaseous hydrocarbon when burnt i 2 2 excess of O gave 2 5 L of CO and 3 0 L of wate vapours under same conditions Molecular formul of the hydrocarbon is 1 CH 3 C H 0 2 C H 0 10 4 C H 2 I

Consider following graph of adsorption x mass of gas absorbed on mass m of adsorbent x E m x E Pressure Graph A Select the correct statement 1 Graph A is for multilayered adsorption 2 Graph B is for monolayered adsorption 3 Graph A is for chemisorption 4 Graph B is for chemisorption Pressure Graph B

ger Type 1 The volume in mL of 0 1 M AgNO for precipitation of chloride ions present in 30 mL solution of Cr H O CIJCL as silver chloride IIT JI to Reaction of Br with Na CO3 in aqueous solut sodium bromide and sodium bromate with of CO gas The number of sodium bromide r involved in the balanced chemical equation is UT JE

Fe SO 9H 0 solution for complete oxidation Calculate the num of gram mole of hydrated ferric sulphate in mixtu b The vapour density of a mixture consisting of and N O is 38 3 at 26 7 C Calculate the numbe moles of NO in 100 g of the mixture IT JEE 19 In the analysis of 0 500 g sample of feldspar a mix of the chlorides of sodium and potassium is obtai which weighs 0 1180 g Subsequent treatment of mixed chlorides with silver nitrate gives 0 2451 of a si chloride What is the percentage of sodium oxide IIT JEE 19 potassium oxide in feldspar If 5 mL of a gas containing only carbon and hydre is mixed with an excess of oxygen 30 mL and mixture is exploded by means of an electric spark volume of the mixed gases become 25 mL On addi concentrated solution of potassium hydroxide the vol further decreases to 15 mL and the residual gas being oxygen All volumes have been reduced to STP Calc the molecular formula of the hydrocarbon gas IIT JEE 1 a Take 1 L of a mixture of CO and CO Pass this mi through a tube containing red hot charcoal The now becomes 1 6 L The volumes are measured u the same conditions Find the composition o mixture by volume

1 Some of the batteries have alkaline electrolytes I Mercury battery II Nickel cadmium III Modified Leclanche cell Cell potential is independent of OH in b I and II d Only III a I II and III c II and III

Chromium metal is plated using the following reaction in acidic solution CrO3 6H 6e Cr 3H O How many grams of chromium will be plated out by 24 000C Atomic mass of chromium is 52 A 1 1554g B 2 1554g skipped

Ompound contains 28 percent of nitrogen and 72 ent of a metal by weight Three atoms of the metal bine with two atoms of N Find the atomic weight e metal 10 bonisane 04 IIT JEE 1980 me equivalent weight of H PO4 in the following n or fol olhosle booubor doble mulbom OH 2 H PO4 CaHPO4 2H Outoz leme ods ai borgiseld IIT JEE 1980 xylamine reduces iron III according to the ing reaction Im 2528d thai OH Fe N O g H O 4Fe2 4H I thus produced is estimated by titration with a section is Th C S 12 a 10 13

Which of the following is not correct 1 Molar conductance of a solution increases with dilution 2 Equivalent conductance increases with dilution 3 Specific conductance increases with dilution 4 At infinite dilution each ion cation or anion plays a definite role towards electrical conductance

2 Example 7 26 N and O combine at a given temperature to produce NO At equilibrium the yield of NO is x percent by K a b volume Ifx Ka b where K is the equilibrium 4 constant of the given reaction at the given temperature and a and b are the volume percentage of N and O respectively in the initial state Report the maximum value of K at which X is maximum 9

16 An acid solution of 0 2 mol of KReO was reduce Zn and then titrated with 1 6 Eq of acidic KMnO4 sc For the reoxidation of all the rhenium Re to the per ion ReO4 Assuming that rhenium was the only e reduced what is the oxidate state to which rheniu reduced by Zn a 1 b 2 c 1 d 2 7 A 200 mL solution of I is divided into two L parts Part I reacts with hypo solution in acidic and requires 8 mL of 2 M hypo solution for ce neutralisation Part II was added with 300 mL of 0 1 M NaOH s

Q47 Compound contains atoms2 2 elements A B and C If the oxidation of three number of A is 2 B is 5 and that of C is 2 the possible formula of the compound is A2 21HED A B C 3x 40 CBA3 BC4 2 C A3 B4C 2 D ABC A A BC3 2 A BC 3x 10 8 3x 40 4 2 5 2 Q 47 a 3x 10 16 02 12 A A BC3 2 B A3 BC4 2 C A3 B4C 2 D ABC 2 Q 48 The General mechanism of electrophilic substitution has key step 2 5 2 u 3 A B 31 2 5 a F 2x 10 6 0 2x 40 edg 6 48 31 46 U 10 6 0 METRO