52671 + Interview Questions in Chemistry in Class 11

1.	At certain temperature, the H^(+) ion concentration of water is 4 xx 10^(-7) 'M then the value of K_(w), at the same temperature is
Answer» `10 ^(-14) M^(2) ` ` 4xx10 ^(-14) M^(2) ` ` 1.6 xx 10 ^(-13) M^(2) ` ` 4xx10 ^(-7) M^(2) ` SOLUTION :` [H^(+) ] [OH^(-)]= K_W , As [H^(+) ] =[OH^(-)] ` ` (4xx10 ^(-17))(4XX 10^(-17)) = K_W` ` 16 xx 10 ^(-14)M^(2)(or) 1.6 xx 10^(-13)M^(2) `

Discussion

2.	At certain temperature RMS velocity of ethane molecules is 5.33 xx 10^(4) cm s^(-1). Find the RMS velocity of carbondioxide at the same temperature.
Answer» SOLUTION :`4.4 XX 10^(4) cms^(-1)`

Discussion

3.	At certain temperature and under a pressure of 4 atm , PCl_(5) is 10 % dissociated . Calculate the pressure at which PCl_(5) will be 20 % dissociated at temperature remaining constant .
Answer» Solution :Calculation of `K_(P)` `{:(PCl_(5) (g) , to , PCl_(3) (g)+ Cl_(2) (g)) , (1 , ," "0 "" 0) , ((1 - alpha) , , ""alpha "" alpha):}` Total no. of moles in the EQUILIBRIUM mixture = `1 - alpha + alpha + alpha = (1 + alpha)` mol . Let the total pressure of equilibrium mixture = p atm Partial pressure of `PCl_(5) , P_(PCl_(5)) = (1 - alpha)/(1 + alpha)xx p` atm Partial pressure of `PCl_(3) = (alpha)/(1 + alpha) xx p` atm Partial pressure of `Cl_(2) , PCl_(2) = (alpha)/(1 + alpha) xx p` atm `K_(p) = (P_(PCl_(2)) xx P_(Cl_(2)))/(P_(PCl_(3))) = (((alpha)/(1 + alpha) p " atm" ) xx ((alpha)/(1 + alpha) p atm))/((1-alpha)/(1 + alpha) p atm) = (alpha^(2) p)/(1 - alpha^(2))` P = 4 atm and `alpha = 10% = (10)/(100) = 0.1` `K_(p) = ((0.1) xx (0.1) xx (4 atm))/(1 - (0.1)^(2)) = (0.04)/(0.99) = 0.04` atm Calculation of P under NEW condition `alpha = 0.2 , K_(p) = 0.04` atm `K_(p) = (alpha^(2) p)/(1 - alpha^(2)) ` or p = `(K_(p) ( 1 - alpha^(2)))/(alpha^(2))` `= ((0.04 atm) [(1- (0.2)^(2))])/((0.2)^(2)) = (0.04 atmxx 0.96)/(0.04)` `= 0.96` atm

Discussion

4.	At certain temperature 28 gm of N_(2) and 6 gm of H_(2) are taken in a 2 lit vessel in Haber's process if concentration of N_2 at equilibrium is
Answer» Greater than the concentration of `H_2` Greater than the concentration of `NH_(3)` LOWER than the concentration of `H_2` Equal to the concentration of `H_(2)` ANSWER :C

Discussion

5.	At Boyle's temperature the value of compressibility factor Z=(PV_(m)//RT=V_("real")//V_("ideal")) has a value of 1, over wide range of pressure. This is due to the fact that in the van der Waal's equation:
Answer» the CONSTANT 'a' is negligible and not 'b' the constant 'b' is negligible and not 'a' both the constant 'a' and 'b' are negligible the EFFECT produced DUE to the molecular attractions compensates the effect produced due to the molecular volume. ANSWER :d

Discussion

6.	At Boyle temperature,
Answer» the effects of the REPULSIVE and atractive INTERMOLECULAR FORCES just cancelled each other the repulsive intermolecular forces are greater than the ATTRACTIVE intermolecular forces the repulsive intermolecular forces are less than the attractive intermolecular forces `b- a/(RT) GT 0` Solution :At `T_b, Z = 1, b = a/(RT)`.

Discussion

7.	At atmospheric pressure ices crystallised in the ......... form but at very low temperature it condenses to ......... form.
Answer» ANSWER :HEXAGONAL, CUBIC.

Discussion

8.	At atmospheric pressure ice crystallises in __________ for.
Answer» ANSWER : HEXAGONAL

Discussion

9.	At any top of the mountain the thermoneterreads 0^(@)C and the harometer reads 710 mm Hg. At the bottom of the mountain the temperature is 40^(@)C and pressure is 760mm Hg. Ratio of density of air at the top with that at the bottom is:
Answer» `1:1` `1.07:1` `1:1.07` `1:1.5` ANSWER :B

Discussion

10.	At any temperature ,the proton concentration of water is
Answer» `10^(7) M` ` LT 10 ^(-7) M` ` gt 10 ^(-7) M` ` sqrt ( K_W) ` Solution :In water` [H^(+) ] ={OH^(-) }=sqrt(K_W)` at ` 25^(@)C, K_W =10 ^(-14) `

Discussion

11.	At any temperature,P^(H)+P^(OH)is equal to
Answer» <P>`7` `0` `14` `P^(K_W) ` Solution :` [H^(+) ] [OH^(-)] K_W rArr P^(H)+P^(OH)= PK_W `

Discussion

12.	At absolute zero which of the following statements about an ideal gas are correct ? a) The motion of gaseous molecules ceases b) The volume of gas increases by 273 times c) The K.E of gas molecules increases ab normally d) The volume of a gas becomes zero
Answer» B, d b, C c, d a, d ANSWER :D

Discussion

13.	At absoloute zero
Answer» Only para-hydrogen exists Only ortho hydrogen exists Both para-and othro-hydrogen exist `BETA`-hydrogen exists Solution :At ABOSOLUTE ZERO TEMP only para-hydrogen exist

Discussion

14.	At a temperature of absolute zero an intrinsic semiconductor is
Answer» an INSULATOR a p-type semiconductor a n-type semiconductor a conductor Solution :At 0K an INTRINSIC semiconductoris an insulator.

Discussion

15.	At a particular temperature, why vapour pressure of acetone is less that than of ether ?
Answer» SOLUTION :This is because the INTERMOLECULAR forces of ATTRACTION in acetone are stronger than those present in ETHER.

Discussion

16.	At a particular temperature, a certain quantity ofgas occupies a volume of 74 "cm"^3 at a pressure of 760 mm. If the pressure is decreased to 740 mm, what will be the volume ofthe gas at the sametemperaute ?
Answer» Solution :In this case, `P_1 = 760 mm "" P_2 = 740 mm` `V_1 = 74 cm^3 "" V_2` = ? ACCORDING to Boyle.s LAW, at CONSTANT temperature `P_1 V_1 = P_2 V_2` or `V_2= (P_1 V_1)/(P_2) = (760xx74)/(740) = 76 cm^3`

Discussion

17.	At a particular temperature and pressure, if the number of moles of an ideal gas is increased by 50% then-
Answer» final VOLUME of the gas will be 1.5 times of its iniital volume most PROBABLE velocity of gas molecules becomes 1.5 times of its INITIAL value total kinetic energy of the gas molecules becomes 1.5 times of its initial value density of gas becomes 1.5 times of its initial value. Answer :A::C

Discussion

18.	At a particular temperature and atmospheric pressure, the solid and liquid phases of a pure substance can exist in equilibrium. Which of the following term defines this temperature ?
Answer» NORMAL melting point Equilibrium temperature Boiling point Freezing point Solution :At definite a infinite temperature and atmospheric pressure, the solid and LIQUID phases of a PURE substance can exist as Solid `hArr` liquid. They exists at normal melting point or normal freezing point.

Discussion

19.	At a particular temperature and atmospheric pressure, the solid and liquidphases of a pure substance can exist in equilibrium. Which of substance can exist in equilibrium. Which of the following term defines this temperature ?
Answer» Normal melting POINT EQUILIBRIUM temperature Boiling point Freezing point Solution :SOLID `hArr` LIQUID equilibrium exists at normal melting point or normal freezing point.

Discussion

20.	At a given temperature, When an acid is added to water then the value of K_(w)
Answer» Decreases Increases Remains same First decreases then increases. SOLUTION :`K_W` does not change with solution ADDITION of acid or BASE

Discussion

21.	At a given temperature the ratio of RMS and average velocities is
Answer» `1.086:1` `1:1.086` `2:1.086` `1.086:2` SOLUTION :`BARC : C : C = 1 : 1.128 : 1.224 IMPLIES C/(barC) = (1.086)/1`

Discussion

22.	At a given temperature, Ke is 4 for the reaction H_(2(g)) + CO_(2(g)) hArr H_(2)O_((g)) + CO_((g)). Initially 0.6 moles each of H_(2) and CO_(2) are taken in 1lit flask. The equilibrium concentration of H_(2) O_((g)) is
Answer» 0.4M 0.46M 0.2M 0.8M Solution : `K_(c)=(X^(2))/((0.6-x)^(2))=4 implies (x)/(0.6-x)=2` x=1.2-3x, 3x=1.2, `x=0.4=[H_(2)O]`

Discussion

23.	At a given temperature and pressure, the equilibrium constant values for the equilibria 3A_2+B_2+2Coverset(K_1)hArr 2A_3BCoverset(K_2)hArr(3)/(2)[A_2]+1/2+C The relation between K_1 and K_2 is ……..
Answer» `K_1=(1)/(sqrt(k_2))` `K_2=K_(1)^(-1/2)` `K_(1)^(2)=2K_2` `(K_1)/(2)=K_2` Solution :`K_1=([A_3BC]^(2))/([A_2]^(3)[B_2][C]^(2))`...(1)`K_2=([A_2]^(3/2)[B_2]^(1/2)[C])/([A_3BC])` `IMPLIES``K_1=([A_2]^(3)[B_2][C]^(2))/([A_3BC]^(2))`...(2) COMPARING (1) & (2), `K_2^2 =(1)/(K_1)impliesK_2=K_1^(-1/2)`

Discussion

24.	At a given temperature and pressure, the equilibrium constant values for the equilibria 3A_(2)+B_(2)+2Coverset(K_(1))(hArr)2A_(3)BC and A_(3)BCoverset(K_(2))(hArr)3/2[A_(2)]+(1)/(2)B_(2)+C The relation between K_(1) and K_(2) is
Answer» `K_(1)=(1)/(sqrt(K_(2)))` `K_(2)=K_(1)^(-1//2)` `K_(1)^(2)=2K_(2)` `(K_(1))/(2)=K_(2)` ANSWER :B

Discussion

25.	At a given temperature and pressure, the equilibrium constant values for the equilibria 3A_2 + B_2 + 2C overset(K_1)hArr 2A_3 BC and A_3 BC overset(K_2)hArr 3/2[A_2] + 1/2B_2 +C The relation between K_1 and K_2 is
Answer» `k_1 = 1/sqrtK_2` `K_2 = K_1^((-1)/2)` `K_1^2 = 2k_2` `K_1/2 = K_2` Solution :`K_1 = ([A_3BC]^2)/([A_2]^3[B_2][C]^2)`…(1) `K_2= ([A]^(3/2)[B_2]^(1/2)[C])/([A_3BC])` `rArr K_2^2 =([A_2]^3[B_2][C]^2)/([A_3BC]^2)`...(2) COMPARING (1) & (2), `K_2^2 = 1/K_1 rArrK_2= K_1^((-1)/2)`

Discussion

26.	At a given temperature and pressure, 20mL of air diffused through a porous membrance in 15 second. Calculate the volume of carbon dioxide which will diffuse in 10 seconds if the vapour density of air is 14.48
Answer» ANSWER :`10.8 ML`

Discussion

27.	At a constant volume, a quantity of an ideal gas has a pressureof 800 mm Hg at 300 K. At what pressure, the temperature will be halved ?
Answer» 1400 MM HG 1000 mm Hg 250 mmHg 400 mm Hg ANSWER :d

Discussion

28.	At a constant temperature, a gas occupies a valume of 500 ml under a pressure of 500 ml under a pressure of 0.82 bar. What will be its volume under a pressure of 1.5 bar ?
Answer» Solution :`P_(1)=082` bar, `P_(2)=15` bar , `V_(1)=500 ml, V_(2) ?` `P_(1)V_(1)=P_(2),V_(2), V_(2)=(P_(1)V_(1))/(P_(2))=(082xx500)/(15)` `:. V_(2)=273*33ml`

Discussion

29.	At a constant temperature a gas is initially at 2 atm pressure. To compress it to 1/8th of its initial volume, pressure to be applied is
Answer» 4ATM 12 ATM 12atm 16ATM ANSWER :D

Discussion

30.	At a constant temperature, a container of fixed vo,ume holds NH_(3) and HCl gases. Can dalton's law of partial pressures be applied to this gases mixture?
Answer» Solution :DALTON's law of partial pressure is APPLICABLE only to a mixture composed to TWO or more nono-reacting gases. `NH_(3)` and HCl gasea react together to produce `NH_(4)Cl`. So dalton's law of partial pressure will not e applicable in this case.

Discussion

31.	At a constant pressure, the density of a certain amount of an ideal gas is "____________".
Answer» DIRECTLY PROPORTIONAL to the temperature inversely proportional to the temperature directly proportional to the SQUARE of the temperature. independent of a temperature Answer :B

Discussion

32.	At a certain temperature 'T',the endothermic reaction A rarrB proceeds virtually to the end. Determine. (i) Signof DeltaS for this reaction(ii) sign of DeltaS for the reaction B rarr A at the temperature T, and (iii) the possibility of reaction B rarr A proceeding at a low temperature.
Answer» Solution :(i) Energyfactor opposes. So enthalpy factor must favour, i.e.,`DELTAS` must be positive. (II) For `A rarr B, DeltaG` is `-ve` , therefore,for `B rarr A,DeltaG` will be `+ve`. (III) For `B rarr A , DeltaH = -ve` and `DeltaS` is ALSO `-ve , i.e.,DeltaS` opposes the process but a lowtemp.,`T DeltaS`may be so low that `DeltaH`is greater in magnitude than `T DeltaS` and the process will be SPONTANEOUS.

Discussion

33.	At a certain temperature ,the solubility of the salt M_m A_nin water is .s. moles per litre. The solubility product of the salt is
Answer» `M^(m)A^(N) ` ` (m+n)s^(m+n) ` ` m^(m) n^(n) S^(m+n) ` `M^(m) A^(n)s.` Solution :` M_m A_n HARR m UNDERSET( ms) M^(n+) + n underset( ns ) A ^(m-)` ` KsP=(ms) ^(m)(ns) ^(n)=m^(m) n^(n) s^(m+n) `

Discussion

34.	At a certain temperature, the equilibrium constant K_(c) is 1 for the reaction, SO_((g))+NO_(2(g))hArrSO_(3(g))+NO_((g)) If 1.0 mol each of the four gases is taken in a one litre container the concentration of NO_(2) at equilibrium would is
Answer» 1.6 MOL `L^(-1)` 0.8 mol `L^(-1)` 0.4 mol `L^-1` 0.6 mol `L^(-1)` ANSWER :C

Discussion

35.	At a certain temperature, the degree of dissociation of PCI_(5) was found to be 0.25 under a total pressure of 15 atm. The value of K_(P) for the dissociation of PCl_(5) is
Answer» <P>1 0.25 0.5 0.75 Solution : Given `alpha = 0.25` Total no. of MOLES at equilibrium = `1+alpha=1.25` Total pressure = 15 atm `K_(P)=(P_(PCl_(3)) xx P_(Cl_(2)))/(P_(PCl_(5)))=(((0.25)/(1.25) xx 15)xx((0.25)/(1.25) xx 15))/(((0.75)/(1.25) xx 15))=1`

Discussion

36.	At a certain temperature the equilibrium constant K_c is 0.25 for the reaction A_(2(g))+B_(2(g)) harr C_(2(g))+D_(2(g)) Ifwetake1moleofeachofthefourgasesina10litrecontainer,whatwouldbeequilibrium concentration of A_(2(g))?
Answer» 0.331 M 0.033 M 0.133 M 1.33 M Solution :`A_(2)+B_(2) harr C_(2)+D_(2)` at t=0, `0.1""0.1""0.1""0.1` `Q=1 gt Kimplies` reaction PROCEEDS BACKWARD at eqm `0.1+x""0.1-x""0.1-x` `K=(1)/(4)=((0.1-x)^(2))/((0.1+x)^(2)) implies (1)/(2)=(0.1-x)/(0.1+x) implies x=(0.1)/(3)` `implies [A]_("eqm")=0.1+(0.1)/(3)=(0.4)/(3)=0.133M`

Discussion

37.	At a certain temperature 'T', endothermic reaction A rarr B proceeds virtually to the end. Determine the sign of Delta S for the reaction A rarr B and Delta G for the reverse reaction B rarr A.
Answer» Solution :`Delta S = +ve, Delta H = +ve, Delta G = -ve` and the reaction proceeds virtually to the end. The in REVERSE reaction `B RARR A, Delta S = -ve, Delta G = +ve`.

Discussion

38.	At a certain temperature and total pressure of 10^(5) Pa. iodine vapours conatain 40% by volume of idine atoms in the equilibrium I_(2)(g) hArr 2I(g) Calculate K_p for the equilibrium.
Answer» Solution :According to availabel data: Total PRESSUE of equilibrium misture `=10^5pa` Partial pressure of iodine molecules `(I_2) = (60)/(100) xx (10^5 Pa) = 0.6 xx 10^(5)` Pa `I_(2)(g) hArr 2I(g)` `(0.6 xx 105 pa) (0.4 xx 105 Pa)` `K_(p) = (P_I^2)/(P_1) = ((0.4 xx 10^2 Pa)^2)/((0.6 xx 10^5 Pa))=2.67 xx 10^4 pa`

Discussion

39.	At a certain temperature and total pressure of 10^5 Pa, iodine vapour contains 40% by volume of I atoms I_(2(g)) hArr 2I_((g)) . Calculate K_p for the equilibrium.
Answer» Solution :At equilibrium total pressure = `10^5` Pa Partial pressure`prop` Percentage by volume of gas, CONCENTRATION of atom of I= 40% by volume `THEREFORE p_1`=40% of (Total pressure) `=(10)^5 (40//100)=0.40xx10^5` Pa `p_(I_2)`= 60% of `10^5 =10^5 xx 0.60` `=0.60xx10^5` Pa Equilibrium reaction = `I_(2(g)) hArr 2I_((g))` `therefore K_p=(p_I)^2/(p_(I_2))=(0.40xx10^5)^2/(0.60xx10^5)= 0.2667xx10^5` `=2.667xx10^4` Pa

Discussion

40.	At a certain temperature and total pressure of 10^5 Pa ,iodine vapour contains 40% by volume of iodine atoms. Calaulate K_p for the equilibrium, 1_2(g)iff2I(g).
Answer» Solution :Percentage by VOLUME of gaseous iodine atoms=`40%` `therefore` Mole fraction of gaseous iodine ATOME =`40/100` `therefore` Partial pressure of gaseous iodine atome= `40/100xx10^5Pa=0.4xx10^5Pa` Partial pressure of gaseous `I_2=0.6xx10^5 PA` `therefore K_p=P_I^2/P_(I_2)=(0.4xx10^5)^2/(0.6xx10^5)=2.67xx10^4Pa`

Discussion

41.	At a certain temperature and total pressure of 10^(5)Pa, iodine vapour contains 40% by volume of I atoms I_(2)(g)hArr2I(g) Calculate K_(p) for the equilibrium
Answer» `0.67` `1.5` `2.67 XX 10^(4)` `9.0 xx 10^(4)` ANSWER :C

Discussion

42.	At 8.2^@C, 0.778 mol dm^-3of N_2O_4 and 2.84 times 10^-3 mol dm^-3 of NO_2 were observed in certain experiment in a chloroform solution. Calculate the value of equilibrium constant for the reaction, 2NO_2(g) leftrightarrow N_2O_4 (g).
Answer» SOLUTION :`9.6 TIMES 10^4 dm^3 mol^-1`

Discussion

43.	At 817^(@)C, K_(p) for the reaction between CO_(2) (g) and excess hot graphite (s) is 10 atm (a) What are the equilibrium concentrations of the gases at817^(@)C and a total pressure of 5 atm ? (b) At what total pressure, the gas contains 5 % CO_(2) by voume ?
Answer» Solution :(a) ` CO_(2) + C(g) hArr2 CO (g)` Supposeat equilibrium , pressure of `CO_(p_CO_(2)) = p "atm "` Then pressureof ` CO_(2) (p_(CO_(2)))= 5 - p " atm " ` ` K_(p) (p_(CO)^(2))/(p_(CO_(2)))= (p^(2))/((5 - p))"" = 10 or p^(2) + 10 p - 50 = 0 ` or `p = ( -b pm sqrt (b^(2) - 4AC))/(2a) = (-10 pm sqrt ( 100- (-200)))/2 = 3* 66" atm " ` Thus , at eqm.` p _(CO) = 3 * 6 "atm " ` ` p_(CO_(2)) = 5 - 3* 66 = 1* 34 "atm "` Applying` PV = nRT or n/V = P /(RT) , i.e ., "molar conc." = P/(RT) ` Molar conc. of `CO = (366)/(0 0821 xx ( 817 + 273)) = 0041 " mol"L ^(-1)` Molar conc. of ` CO_(2) = (134)/(00821 xx 1090 ) = 0 015 " mol" L^(-1)` (b) When the gas contains 5 % `CO_(2)`by volume , this MEANS that pressure EXERTED by `CO_(2) ` is also5 %of the total pressure . Thus, if P is the total pressure , then at equilibrium , ` p_(CO_(2)) =005 P and p_(CO) = 0 95 P ` ` K_(P)= (p_(CO)^(2))/p_(CO^(2))= (095 P)^(2)/((0 05 P)) = 10 or 18* 05 P= 10 or P = 0* 554 "atm "`

Discussion

44.	At 740 torr pressure volume of N_(2) gas is 800 mL, if volume becomes 540 mL then calculate pressure of gas ?
Answer» ANSWER :356.3 TORR

Discussion

45.	At 717 K 3.2 mol HI heated in a close tube. 20% I decompose at equilibrium 2HI_((g)) hArr H_(2(g))+ I_(2(g))and find K_c and mol of HI, H_2 and I_2.
Answer» SOLUTION :K=0.0156 , MOLE `H_2` and `I_2` : 0.32 for both, HI:2.56 MOL

Discussion

46.	At 700K, the equilibrium constant K_(p), for the reaction 2SO_(3(g))hArr2SO_(2(g))+O_(2(g)) is 1.8xx10^(-3) atm. The value of K_(c) for the above reaction at the same temperature in moles per litre would be
Answer» <P>`1.1xx10^(7)` `6.2xx10^(-7)` `3.1xx10^(-5)` `9.3xx10^(-7)` Solution :`K_(p)=K_(c)(RT)^(DELTAN),Deltan=3-2=1` `1.8xx10^(-3)=K_(c)(0.0832xx700)^(1),` `K_(c)=(1.8xx10^(-3))/(0.0832xx700)=3.09xx10^(-5)`

Discussion

47.	At 700 K the equilibrium constant K_(p) for the reaction 2 SO_(3) (g) hArr 2 SO_(2) (g) + O_(2) (g) is 1.80 xx10^(-3)kPa. What is the numerical value of K_(c) in moles per litre for this reaction at the same temperature ?
Answer» Solution :Here `n_(p) =3 " moles" , n_(r) = 2 " moles "` `:. " "DELTAN = n_(p) - n _(r) = 3- 2 = 1 ` ` K_(p) = 1.80 xx 10^(-3) kPA = 1. 80 PA = (1.80)/(10^(5)) "bar" = 1.80 xx 106(-5) " bar"` `R= 0.0831 L " bar " K^(-1) mol^(-1), T=700 K` USING the relation , `K_(p) = K_(C) (RT)^Delta n` `K_(c) = (K_(p))/(RT)= (1.80 xx 10^(-5) "bar")/(0.0831 L " bar " K^(-1) xx 700 K )= 3.09 xx 106(-7) " mol " L^(-1)` `" Alternatively, " K_(c) = (K_(p))/(RT) =(1.8Pa)/((8.314 JK^(-1) mol^(-1))(700 K))""( :' Pa = N m^(-2), J = N m)` `= 3.09 xx 10^(-4)" mol " m^(-3) = 3.09 xx 10^(-7)" mol " dm^(-3) or" mol " L^(-1)`

Discussion

48.	At 700 K , the equilibrium constant for the reaction : H_2(g) + I_2(g) hArr 2HI(g)is 54.8 . If 0.5 mol L^(-1)of HI(g) is present at equilibrium at 700 K, what are the concentrationof H_2(g) and I_2(g) assuming that we initially started with HI(g) and allowed it to reach equilibrium at 700 K ?
Answer» Solution :`{:(,2HI(G) hArr,H_2(g) +, I_2),("At equi.",0.5,X,x):}` `K_c=([H_2][I_2])/[HI]^2=1/54.8` `x^2/(0.5)^2=1/54.8` `x^2=0.25/54.4.56xx10^(-3)` x=0.068 `[H_2]=[I_2]="0.068 mol L"^(-1)`

Discussion

49.	At 700 k, hydrogen and bromine react to form bromine react to form hydrogen bromide. The value of equilibrium constant for this reaction is5 xx 10^(8). .Claculate the amount of H_(2), Br_(2) and HBr " at equilibrium it a mixture of" 06" mole of "H_(2) and 02 " mole of "Br_(2)is heated to700 K.
Answer» Solution :`{:(,PCl_(5)(g),hArr,PCl_(3) (g) ,+,Cl_(2)(g)),("Initial",300 " mol ",,0,,0),("At. eqm.",(30 - x)" mol ",,x " mol" ,,x " mol" ),("MOLAR CONC.",(30-x),,x,,x):}` `{:(,H_(2),+,Br_(2),hArr,2 HBr),("Intial amounts",06"mole",,02 "mole",,),("Amount at eqm.",(06-x),,(02 - x),,2" x moles"),("Molar cones at eqm.",((06-x)/V),,(02 -x)/V,,(2x)/V mol L^(-1)):}` ( V= Volumeof reaction mixture) `K= ((2x//V)^(2))/((06-x)/V xx(02 -x)/V)=(4x^(2))/((06-x)(02-x))= 5 xx 10^(8)` or `(4x^(2))/((012- 08 x +x^(2)))=5 xx 10^(8) or (x^(2) - 08 x + 012) xx 5 xx 10^(8) = 4 x^(2)` Neglecting `4x^(2) " in comparison to " 5 xx 10^(8) x^(2), (i.e., "taking 4 "x^(2)=0) ` we get `x^(2) - - 08 x + 0* 12 = 0` ` x= ( 08 pm sqrt((08)^(2) - 4 xx 012))/2=(08 pm 0693)/2= 07465 and 00535` ` x= 0 7465 " is impossible ( because initially", H_(2) = 06 "mole")` Hence, `x= 00535` `:. "Amounts at equilibrium will be " ` `H_(2) = 06 - 00535 = 05465" mole"` `Br_(2) = 02 - 00535 = 01465 " mole " ` `HBr = 2 xx 00535 = 01070 " mole"`

Discussion

50.	At 700 K H_2 and I_2 with reaction H_(2(g)) + I_(2(g)) hArr 2HI_((g))in K_c = 57.0. At t time [H_2]_t = 0.1 M, [I_2]_t = 0.2 M and [HI]_t = 0.40. After t timereaction proceed in which direction ?
Answer» Solution :`{:("Equilibrium reaction :",H_(2(g)) + , I_(2(g)) HARR , 2HI_((g))),("Concentration at t time :",0.10 M, 0.02 M , 0.40 M):}` At t time the reaction quotient `Q_c`, `Q_c=[HI]^2/([H_2][I_2])=(0.4)^2/((0.1)(0.2))`=8.0 Thus, `Q_c`(8.0) `lt K_c` (57.0) The VALUE of `Q_c` is LESS, so reaction will proceed in the direction of the product (forward reaction) till the value of `Q_c` is EQUAL to `K_c` (57.0). The reaction is continue.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

At certain temperature, the H^(+) ion concentration of water is 4 xx 10^(-7) 'M then the value of K_(w), at the same temperature is

At certain temperature RMS velocity of ethane molecules is 5.33 xx 10^(4) cm s^(-1). Find the RMS velocity of carbondioxide at the same temperature.

At certain temperature and under a pressure of 4 atm , PCl_(5) is 10 % dissociated . Calculate the pressure at which PCl_(5) will be 20 % dissociated at temperature remaining constant .

At certain temperature 28 gm of N_(2) and 6 gm of H_(2) are taken in a 2 lit vessel in Haber's process if concentration of N_2 at equilibrium is

At Boyle's temperature the value of compressibility factor Z=(PV_(m)//RT=V_("real")//V_("ideal")) has a value of 1, over wide range of pressure. This is due to the fact that in the van der Waal's equation:

At Boyle temperature,

At atmospheric pressure ices crystallised in the ......... form but at very low temperature it condenses to ......... form.

At atmospheric pressure ice crystallises in __________ for.

At any top of the mountain the thermoneterreads 0^(@)C and the harometer reads 710 mm Hg. At the bottom of the mountain the temperature is 40^(@)C and pressure is 760mm Hg. Ratio of density of air at the top with that at the bottom is:

At any temperature ,the proton concentration of water is

At any temperature,P^(H)+P^(OH)is equal to

At absolute zero which of the following statements about an ideal gas are correct ? a) The motion of gaseous molecules ceases b) The volume of gas increases by 273 times c) The K.E of gas molecules increases ab normally d) The volume of a gas becomes zero

At absoloute zero

At a temperature of absolute zero an intrinsic semiconductor is

At a particular temperature, why vapour pressure of acetone is less that than of ether ?

At a particular temperature, a certain quantity ofgas occupies a volume of 74 "cm"^3 at a pressure of 760 mm. If the pressure is decreased to 740 mm, what will be the volume ofthe gas at the sametemperaute ?

At a particular temperature and pressure, if the number of moles of an ideal gas is increased by 50% then-

At a particular temperature and atmospheric pressure, the solid and liquid phases of a pure substance can exist in equilibrium. Which of the following term defines this temperature ?

At a particular temperature and atmospheric pressure, the solid and liquidphases of a pure substance can exist in equilibrium. Which of substance can exist in equilibrium. Which of the following term defines this temperature ?

At a given temperature, When an acid is added to water then the value of K_(w)

At a given temperature the ratio of RMS and average velocities is

At a given temperature, Ke is 4 for the reaction H_(2(g)) + CO_(2(g)) hArr H_(2)O_((g)) + CO_((g)). Initially 0.6 moles each of H_(2) and CO_(2) are taken in 1lit flask. The equilibrium concentration of H_(2) O_((g)) is

At a given temperature and pressure, the equilibrium constant values for the equilibria 3A_2+B_2+2Coverset(K_1)hArr 2A_3BCoverset(K_2)hArr(3)/(2)[A_2]+1/2+C The relation between K_1 and K_2 is ……..

At a given temperature and pressure, the equilibrium constant values for the equilibria 3A_(2)+B_(2)+2Coverset(K_(1))(hArr)2A_(3)BC and A_(3)BCoverset(K_(2))(hArr)3/2[A_(2)]+(1)/(2)B_(2)+C The relation between K_(1) and K_(2) is

At a given temperature and pressure, the equilibrium constant values for the equilibria 3A_2 + B_2 + 2C overset(K_1)hArr 2A_3 BC and A_3 BC overset(K_2)hArr 3/2[A_2] + 1/2B_2 +C The relation between K_1 and K_2 is

At a given temperature and pressure, 20mL of air diffused through a porous membrance in 15 second. Calculate the volume of carbon dioxide which will diffuse in 10 seconds if the vapour density of air is 14.48

At a constant volume, a quantity of an ideal gas has a pressureof 800 mm Hg at 300 K. At what pressure, the temperature will be halved ?

At a constant temperature, a gas occupies a valume of 500 ml under a pressure of 500 ml under a pressure of 0.82 bar. What will be its volume under a pressure of 1.5 bar ?

At a constant temperature a gas is initially at 2 atm pressure. To compress it to 1/8th of its initial volume, pressure to be applied is

At a constant temperature, a container of fixed vo,ume holds NH_(3) and HCl gases. Can dalton's law of partial pressures be applied to this gases mixture?

At a constant pressure, the density of a certain amount of an ideal gas is "____________".

At a certain temperature 'T',the endothermic reaction A rarrB proceeds virtually to the end. Determine. (i) Signof DeltaS for this reaction(ii) sign of DeltaS for the reaction B rarr A at the temperature T, and (iii) the possibility of reaction B rarr A proceeding at a low temperature.

At a certain temperature ,the solubility of the salt M_m A_nin water is .s. moles per litre. The solubility product of the salt is

At a certain temperature, the equilibrium constant K_(c) is 1 for the reaction, SO_((g))+NO_(2(g))hArrSO_(3(g))+NO_((g)) If 1.0 mol each of the four gases is taken in a one litre container the concentration of NO_(2) at equilibrium would is

At a certain temperature, the degree of dissociation of PCI_(5) was found to be 0.25 under a total pressure of 15 atm. The value of K_(P) for the dissociation of PCl_(5) is

At a certain temperature the equilibrium constant K_c is 0.25 for the reaction A_(2(g))+B_(2(g)) harr C_(2(g))+D_(2(g)) Ifwetake1moleofeachofthefourgasesina10litrecontainer,whatwouldbeequilibrium concentration of A_(2(g))?

At a certain temperature 'T', endothermic reaction A rarr B proceeds virtually to the end. Determine the sign of Delta S for the reaction A rarr B and Delta G for the reverse reaction B rarr A.

At a certain temperature and total pressure of 10^(5) Pa. iodine vapours conatain 40% by volume of idine atoms in the equilibrium I_(2)(g) hArr 2I(g) Calculate K_p for the equilibrium.

At a certain temperature and total pressure of 10^5 Pa, iodine vapour contains 40% by volume of I atoms I_(2(g)) hArr 2I_((g)) . Calculate K_p for the equilibrium.

At a certain temperature and total pressure of 10^5 Pa ,iodine vapour contains 40% by volume of iodine atoms. Calaulate K_p for the equilibrium, 1_2(g)iff2I(g).

At a certain temperature and total pressure of 10^(5)Pa, iodine vapour contains 40% by volume of I atoms I_(2)(g)hArr2I(g) Calculate K_(p) for the equilibrium

At 8.2^@C, 0.778 mol dm^-3of N_2O_4 and 2.84 times 10^-3 mol dm^-3 of NO_2 were observed in certain experiment in a chloroform solution. Calculate the value of equilibrium constant for the reaction, 2NO_2(g) leftrightarrow N_2O_4 (g).

At 817^(@)C, K_(p) for the reaction between CO_(2) (g) and excess hot graphite (s) is 10 atm (a) What are the equilibrium concentrations of the gases at817^(@)C and a total pressure of 5 atm ? (b) At what total pressure, the gas contains 5 % CO_(2) by voume ?

At 740 torr pressure volume of N_(2) gas is 800 mL, if volume becomes 540 mL then calculate pressure of gas ?

At 717 K 3.2 mol HI heated in a close tube. 20% I decompose at equilibrium 2HI_((g)) hArr H_(2(g))+ I_(2(g))and find K_c and mol of HI, H_2 and I_2.

At 700K, the equilibrium constant K_(p), for the reaction 2SO_(3(g))hArr2SO_(2(g))+O_(2(g)) is 1.8xx10^(-3) atm. The value of K_(c) for the above reaction at the same temperature in moles per litre would be

At 700 K the equilibrium constant K_(p) for the reaction 2 SO_(3) (g) hArr 2 SO_(2) (g) + O_(2) (g) is 1.80 xx10^(-3)kPa. What is the numerical value of K_(c) in moles per litre for this reaction at the same temperature ?

At 700 K , the equilibrium constant for the reaction : H_2(g) + I_2(g) hArr 2HI(g)is 54.8 . If 0.5 mol L^(-1)of HI(g) is present at equilibrium at 700 K, what are the concentrationof H_2(g) and I_2(g) assuming that we initially started with HI(g) and allowed it to reach equilibrium at 700 K ?

At 700 k, hydrogen and bromine react to form bromine react to form hydrogen bromide. The value of equilibrium constant for this reaction is5 xx 10^(8). .Claculate the amount of H_(2), Br_(2) and HBr " at equilibrium it a mixture of" 0*6" mole of "H_(2) and 0*2 " mole of "Br_(2)is heated to700 K.

At 700 K H_2 and I_2 with reaction H_(2(g)) + I_(2(g)) hArr 2HI_((g))in K_c = 57.0. At t time [H_2]_t = 0.1 M, [I_2]_t = 0.2 M and [HI]_t = 0.40. After t timereaction proceed in which direction ?

At 700 k, hydrogen and bromine react to form bromine react to form hydrogen bromide. The value of equilibrium constant for this reaction is5 xx 10^(8). .Claculate the amount of H_(2), Br_(2) and HBr " at equilibrium it a mixture of" 06" mole of "H_(2) and 02 " mole of "Br_(2)is heated to700 K.