94420 + Interview Questions in Chemistry in Class 12

1.	At a given temperature, if degree of dissociation of N_2O_4 in the following reaction N_2O_4(g)hArr2NO_2(g) be a, and total pressure of the equilibrium mixture be P, then it can be shown that equilibrium constant for the reaction, K_P = a^2P (assuming a is very small compared to 1). Which of the following comments is true for this relation
Answer» `K_p` increases as P increases `K_p` increases as P increases value of `K_p` does not DEPEND on P but DEPENDS on `PROP` the value of `K_p` depends NEITHER on P nor on `prop` Answer :D

Discussion

2.	At a given temperature if P is the vapour pressure of a solution and P_0 that of its pure solvent , the relative lowerning of vapour pressure of the solution is given by :
Answer» <P>`(P_0 - P) /( P_0)` `(P - P_0)/ (P_0)` `(P_0)/(P)` `(P)/ (P_0)` ANSWER :A

Discussion

3.	At a given temperature and pressure nitrogen gas is more soluble in water than Helium gas. Which one of them has higher value of K_n ?
Answer» SOLUTION :HELIUM

Discussion

4.	At a given temperature and pressure nitrogen gas is more soluble in water than helium gas. Which one of them has higher value of K_(H) ?
Answer» SOLUTION :HELIUM or He.

Discussion

5.	At a given temperature ad pressure, the rate of diffusion of a gas is :
Answer» DIRECTLY proportional to the DENSITY of the gas Directly proportional to the square root of its density of the gas Inversely proportional to the square root of its density. Inversly proportional to the square root of its density Answer :D

Discussion

6.	At a given temperature (a) Vapour pressure of a solution containing nonvolatile solute is proportional to mole fraction of solvent (b) Lowering of vapour pressure of solution containing nonvolatile solute is proportional to mole fraction of solute (c) Relative lowering of vapour pressure is equal to mole fraction of solute
Answer» a only a, B only a, b and C only b, c only ANSWER :C

Discussion

7.	At a given tempeature, osmotic pressure of a concentrated solution of a substance ………….. .
Answer» is HIGHER than that at a dilute solution is lower than that of a dilute solution is same as that of a dilute solution can not be compared with osmotic pressure of dilute solution. Solution :`pi=CRT,` i.e., `pi ALPHA C`

Discussion

8.	At a fixed temperature, a liquid is in equilibrium with its vapours in a closed vessel. Which measurable quantity for the liquid gets fixed at equilibrium?
Answer» Solution :When a liquid remains in equilibrium with its vapours in a closed VESSEL at a particular TEMPERATURE, the vapour pressure of the liquid is found to ACQUIRE a FIXED VALUE.

Discussion

9.	At a constant pressure the amount of heat required to raise the temperature of 1 mol of an ideal gas by 10^(@)C is x kJ. If the same increase in temperature were carried out at constant volume, then the heat required would be-
Answer» `GTX` KJ `LTX` kJ `=X` kJ `GE`x kJ Answer :A

Discussion

10.	At a certain temperature, the vapour pressure( in mm Hg) of CH_(3)OH and C_(2)H_(5)OH solutionis representedbyP = 119 x + 135 where x is themolefractionof CH_(3)OH . Whatare thevapour pressureof pure componentsat thistemperature ?
Answer» Solution :For `CH_(3) OH ,` x = 1 ` thereforeP = 119+135 = 245 mm H` For `C_(2)H_(5)OH , x = 0` `thereforeP = 119 xx 0+135 = 135 mm HG`

Discussion

11.	At a certain temperature, the solubility of the salt M_(m)A_(n)in 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 MM^(+)+NA^(-)` The solubility is s `[M^(+)]=ms, [A^(-)]=ns` `K_(SP)=[M^(+)]^(m)[A^(-)]^(n)` `= (ms)^(m)(ns)^(n)=m^(m)n^(n)s^(m+n)`

Discussion

12.	At a certain temperature the time required for the complete diffusion of 200 mL of H_(2) gas is 30 minutes. The time required for the complete diffusion of 50 mL of O_(2) gas at the same temperature will be
Answer» 60 minutes 30 minutes 45 minutes 15 minutes. Solution :According to Graham.s law of DIFFUSION or effusion. Rate of diffusion of a gas (R) `=("Volume of the gas diffused"(V))/("Time taken for the diffusion"(t))` Now according to Graham.s law. `r prop 1/(SQRT("Molecular mass of the gas"))` i.e. `r prop 1/(sqrt(M))` Now `(r_(H_(2)))/(r_(O_(2)))sqrt((M_(O_(2)))/(M_(H_(2))))implies(200//30)/(50//t)=sqrt(32/2)` Where t is the time taken for diffusion of 50 mL of `O_(2)` gas. `implies200/30xx5/50=4impliest=30` min

Discussion

13.	At a certain temperature, the value of the slope of the plot of osmotic pressure (pi) against concentration ("C in mol L"^(-1)) of a certain polymer solution is 291R. The temperature at which osmotic pressure is measured is (R is gas constant)
Answer» `271^(@)C` `18^(@)C` 564 K 18 K Solution :`pi=CRT`. Thus, a plot of `pi` vs C will be LINEAR with slope =RT. Hence, RT = 291 R or T = 291 K = `(291-273)^(@)C=10^(@)C`

Discussion

14.	At a certain temperature, the half life period for the catalytic decomposition of ammonia was found as follows: Calculate order of the reaction.
Answer» Solution :For the reaction of nth ORDER, `(t_(1//2))_(1)/(t_(1//2))_(2)= {[A_(0)]_(2)/[A_(0)]_(1)}^(N-1)` From the given data, `(3.52)/(1.92) = (13333/6667)^(n-1) = (2)^(n-1)` `(a propto "initial PRESSURE")` `LOG(3.52)/(1.92) = (n-1) log2, 0.2632 = (n-1) xx 0.3010` `n-1 = 0.2632/0.3010 = 0.874, n =1.87 ~~2` The reaction is of second order.

Discussion

15.	At a certain temperature the following equilibrium is established CO(g)+NO_2(g)hArrCO_2(g)+NO(g) One mole of each of the four gas is mixed in one litre container and the reaction is allowed to reach equilibriumstate.When excess of baryta water (Ba(OH)_2) is added to the equilibrium mixture, the weight of white ppt. (BaCO_3) obtained is 236.4 gm.The equilibrium constant K_C of the reaction is (Ba=137)
Answer» 1.2 2.25 2.1 3.6 Solution :`{:(,CO(g)+,NO_2(g)hArr , CO_2(g)+,NO(g)),(t=0,"1 MOLE","1 mole","1 mole","1 mole"),(At eq. , 1-x,1-x,1+x,1+x):}` `CO_2+Ba(OH)_2 to BaCO_3` mole of `BaCO_3=263.4/197=1.2` So mole of `CO_2` at eq. =12 or 1+x=1.2 x=0.2 `K_C=((1+x)/(1-x))^2=((1.2)/(0.8))^2 =2.25`

Discussion

16.	At a certain temperature, the reaction PCl_(5)(g)hArrPCl_(3)(g) + Cl_(2)(g) has an equilibrium constant K_(c) = 5.8 ×x 10^(-2). Calculate the equilibrium concentrations of PCl_(5), PCl_(3) and Cl_(2) if only PCl_(5) is present initially, at a concentration of 0.160 M.
Answer» SOLUTION :`[PCl_(3)] = [Cl_(2)] = 0.071 M, [PCl_(5)] = 0.089`

Discussion

17.	At a certain temperature the dissocation constants of formic acid and acetic acid are 1.8xx10^(-4) and 1.8xx10^(-6) respectively. The concentration of acetic acid solution in which the hydrogen ion has the same concentration as in 0.001 M formic acid solution is equal to
Answer» 0.001 M 0.01 M 0.1 M 0.0001 M Solution :`[H^(+)]=SQRT(C xx K_(a))=sqrt(0.001xx1.8xx10^(-4))` for FORMIC acid `[H^(+)]=sqrt(C_(2)xx1.8xx10^(-5))` for ACETIC acid Equating and SOLVING for `C_(2)=0.01 M`

Discussion

18.	At a certain temperature T, the endothermic reactiion ArarrB proceeds almost to completion. The entropy change is:
Answer» `triangleS=0` `triangleSlt0` `triangleSgt0` Cannot be predicted Answer :C

Discussion

19.	At a certain temperature pure liq. A & liq B have vapour pressure 10 torr and 37 torr respectively. For a certain ideal Solution of A, B the Vapour is equilibrium with the liquid . Molefraction of A in the solution is 0.346. The (P_(B))/(P_(A)) in the solution is .
Answer»

Discussion

20.	At a certain temperature, K_(sp) of AgCl in water is 1.8xx10^(-10). What will be its K_(sp) is a 0.1 M solution of AgNO_(3) at some temperature.
Answer» Solution :At a certain temperature, the solubility of AGCL DECREASES in presence of common ion `(Ag^(+))`, but the SOLUBLITY PRODUCT of AgCl REMAINS the same, therefore, `K_(sp)` for AgCl in 0.1(M) aqueous solution of `AgNO_(3)` will be the same as that in water.

Discussion

21.	At a certain temperature K_(w) is 9.55xx10^(-14). The pH of water at this temperature is :
Answer» `6.51` `4.28` `6.42` `4.62` ANSWER :A

Discussion

22.	At a certain temperature for which RT=25 lit.atm. "mol"^(-1)., the density of a gas, in gas lit^(-1), is d=2.00 P+0.020 P^2, where P is the pressure in atmosphere.The molecular weight of the gas in gm "mol"^(-1) is
Answer» 25 50 75 100 Solution :LT `d/p=M/(RT)IMPLIES M=2RT=50` `Pto0`

Discussion

23.	At a certain temperature equilibrium constant (K_c) is 16 for the reaction. SO_2(g)+NO_2(g) hArr SO_3(g) +NO_((g)) if we take one mole each of the four gases in one litre container, what would be the equilibrium concentration of NO and NO_2?
Answer» ANSWER :0.4 M

Discussion

24.	At a certain temperature and at infinite dilution, the equivalent conductances of sodium benzoate, hydrochloric acid and sodium chloride are 240, 349 and 229ohm^(-1) cm^(2) equiv^(-1) respectively. The equivalent conductance of benzoic acid inohm^(-1) cm^(2) equiv^(-1) at the same conditions is
Answer» 80 328 360 408 Answer :C

Discussion

25.	At a certain temperature and a total pressure of 10^(5) Pa, iodine vapours contain 40% by volume of iodine atoms.I_(2)(g) hArr 2I(g)K_(p) for the equilibrium reaction is :
Answer» `0.6xx10^(5)` `2.67xx10^(4)` `1.98xx10^(4)` `2.67xx10^(3)` ANSWER :B

Discussion

26.	At a certain temperature , 2HI ⇌ H_2 + I_2 on 50 % HIis dissolved at equilibrium .What the value of equilibrium constant ?
Answer» 1 3 0.5 0.25 Answer :D

Discussion

27.	At a certain temperature and a total pressure of 10^(5) Pa, iodine vapours contain 40% by volume of iodine atoms [I_(2(g))iff2I_((g))]. K_(p) for the equilibrium will be
Answer» <P>`0.67` `1.5` `2.67xx10^(4)` `9.0xx10^(4)` SOLUTION :Partial pressure of I atoms `(P_(I))` `=(40)/(100)xx10^(5)Pa=0.40xx10^(5)Pa` Partial pressure of `I_(2)(P_(I_(2)))=(60)/(100)xx10^(5)Pa=0.60xx10^(5)Pa` `K_(p)=(P_(I)^(2))/(P_(I_(2)))=((0.4xx10^(5))^(2))/(0.60xx10^(5))=2.67xx10^(4)`

Discussion

28.	At a certain temp. HIhArrH_(2)+I_(2) only 50% HI is dissociated at equilibrium. The equiliium constant is
Answer» `0.25` `1.0` `3.0` `0.50` SOLUTION :`UNDERSET(50)underset(100)(2HI)hArrunderset(25)underset(0)(H_(2))+underset(25)underset(0)(I_(2))` `([H_(2)][I_(2)])/([HI]^(2))=(25xx25)/(50xx50)=0.25.`

Discussion

29.	At 945^@C and 1 atm, 1.7 g of H_2Soccupies a volume of 5.384 litres. Calculate thedegree of dissociation of hydrogen sulphide if the reaction proceeds according to the equation H_2S= H_2 + 0.5 S_2(v)
Answer» ANSWER :0.156

Discussion

30.	At a certain instant a piece of radioactive material contains 10^(12) atoms. The half-life of the material is 30 days. What will be number of distingrations per second of the sample at that instant?
Answer» `3.96 xx 10^(6)` dps `4.02 xx 10^(5)` dps `2.66 xx 10^(5) ` dps `1.96 xx 10^(6)` dps Solution :`t_(1//2) = 30` days `N_t = 10^(12)` ATOMS Now `lambda = (0.693)/(t_(1//2)) = (0.693)/(30) "days"^(-1)` Again RATE of distintegration of the sample is, `(-dN_t)/(DT) = lambdaN_t = (0.693)/(30) xx 10^(12)` `= 2.31 xx 10^(10)` disintegrations per day = `2.66 xx 10^(5) dps`.

Discussion

31.	At a certain Hill station, water boils at 96^(@)C. The amount of NaCl that should be added to one litre of water so that it boils at 100^(@)C will be (K_(b) for H_(2)O=0.52K//m)
Answer» 450 g 225 g 125 g 250 g Solution :Required `DeltaT_(b)=100-96=4^(@)` `DeltaT_(b)=iK_(b)m=iK_(b)(w_(2))/(M_(2))XX(1)/(w_(1))xx1000` `"i.e.,"4=2xx0.52xx(w_(2))/(58.5)xx(1)/(1000)xx1000` `"or"w_(2)=225g""("1 L "H_(2)O=1000g)`

Discussion

32.	At a boiling point of pure solvent ,solution will not boil because
Answer» V.P. of SOLVENT is LESS than that of SOLUTION V.P. of solvent is EQUAL to that of solution V.P. of solution is less than that of solution all Solution :It is a FACT.

Discussion

33.	At 90^@C, the vapour pressure of toluene is 400 torr and that ofsigma-xylene is 150 torr. What is the composition of the liquid mixture that boils at 90^@C, when the pressure is 0.50 atm? What is the composition of vapour produced?
Answer» ANSWER :92 MOL% TOLUENE; 96.8 mol% toluene

Discussion

34.	At 90^(@)C, the vapour pressure of toluene is 400 mm and that of xylene is 150 mm. What is the composition of the liquid mixture that will boil at 90^(@)C when the pressure of mixture is 0.5 atm?
Answer» Solution :At the boiling point `(90^(@)C)`, Vapour PRESSURE of mixture `P_("total")="0.5 ATM"` `=(760)/(2)mm=380mm` `P_("total")=x_(T)p_(T)^(@)xx x_(X)p_(X)^(@)"(T = Toluene, X = Xylene)"` `=x_(T)p_(T)^(@)+(1-x_(T))p_(X)^(@)` `THEREFORE""380=x_(T)(400)+(1-x_(T))(150)` `""=400x_(T)+150-150x_(T)""(because x_(T)+x_(X)=1)` `""=400x_(T)+150-150x_(T)` `"or"250x_(T)=230 or x_(T)=(230)/(250)=0.92` `therefore""x_(X)=1-0.92=0.08`

Discussion

35.	At 90^(@)C, pure water has [H_(3)O^(+)]=10^(-6)mol L^(-).The value of K_(w) at 90^(@)Cis:
Answer» `1xx10^(-6)` `1xx10^(-8)` `1xx10^(-12)` `1xx10^(-14)` Solution :`K_(w)=[H_(3)O]^(+)[OH^(-)]=[H_(3)O^(+)]^(2)` `=(10^(-6))^(2)=10^(-12)`.

Discussion

36.	At 90^(@)C pure water has [H_(3)O^(+)] = 10^(-6) M, the value of K_(w) at this temperature will be
Answer» `10^(-6)` `10^(-12)` `10^(-14)` `10^(-8)` Solution :For pure WATER `[H^(+)] = [OH^(-)], :. K_(w) = 10^(-12)`.

Discussion

37.	At 90^@C pure water has [H_3O^+] = 10^-6 mol/ litre. The value of K_w at 90^@C is:
Answer» `10^(-6)` `10^(-12)` `10^(-14)` `10^(-8)` Answer :B

Discussion

38.	At 90^(@) C,pH of an aq . Solution of a strong electrolyte is 7 . What is the nature of electrolyte ?
Answer» neutral basic acidic none Answer :2

Discussion

39.	At 88^(o)C benzene has a vapour pressure of 900 torr and toluene has a vapour pressure of 360 torr. What is the mole fraction fo benzene in the mixture with toluene that will boil at 88^(o)C at 1 atm pressure, benzene-toluene from an ideal solution ? (P of mixture = 760 torr)
Answer» <P>0.416 0.588 0.68 0.74 Solution :`P_("mix")=760` TORR because solution BOILS at `88^(@)C` Now `P_(m)=P_("Benzene")^(@)X_("Benzene")^(@)+P_("TOLUENE")^(@) X_("toluene")^(@)` `(X_("toluene")^(@)=1-X_("Benzene")^(@))` `760 = 900 x m.f."of" C_(6)H_(6)+360 xx (1-m.f. "of" C_(6) H_(6))` `"a is mol fraction of" C_(6)H_(6) "then" ` `:. 760 = 900a + 360 -360a,` `:. a = 0.74`

Discussion

40.	At 88^(@)C benzene has a vapour pressure of 900 torr and toluene has vapour pressure of 360 torr. What is the mole fraction of benzene in the mixture with toluene that will be boil at 88^(@)C at 1 atm pressure, benzene- toluene form an idean solution.
Answer» Solution :`P_(S) = 760` torr, because solution boils at `88^(@)C` `:. 760 = 900 a + 360 (1-a)` `a = 0.74` where 'a' is MOLE fration `C_(6)H_(6)`. (ii) For solid -liquid solution: Let us assume `A =` non volatile solid % `B =` volatile liquid According to Raoult's law- `:' P_(s) = X_(A) P_(A)^(0) +X_(B)P_(B)^(0)` for `A, P_(A)^(0 = 0` `:. P_(s) = X_(B)P_(B)^(0)` .....(5) Let `P_(B)^(0) = P^(0) =` Vapour pressure of pure STATE of solvent, here `X_(B)` is mole fraction of solution `P_(s) = (n_(B))/(n_(A) +n_(B)) P^(0)` `P_(S) prop (n_(B))/(n_(A)+n_(B))` i.e vapour pressure of solution `prop` mole fraction of solvent `RARR P_(S) = X_(B)P_(B)^(0) rArr P_(S) = (1- X_(A)) P_(B)^(0) rArr P_(S) = P_(B)^(0) - X_(A) P_(B)^(@) rArr (P_(B)^(@) -P_(S))/(P_(B)^(@)) = X_(A)` or `(P^(@) -P_(S))/(P^(0)) = X_(A)` ....(7), or `(P^(0)-P_(S))/(P^(0)) =(n_(A))/(n_(A)+n_(B))` ..(8) or `(P^(0))/(P^(0)-P_(S)) = (n_(A)+n_(B))/(n_(A))` or `(P^(0))/(P^(0)-P_(S)) = 1 +(n_(B))/(n_(A))` or `(P^(0))/(P^(0)-P_(S)) -1 =(n_(B))/(n_(A))` or `(P_(S))/(P^(0)-P_(S)) = (n_(B))/(n_(A))` `(P^(0)-P_(S))/(P_(S)) =(n_(A))/(n_(B)) = (w_(A)m_(B))/(m_(A)w_(B))` ..(9)

Discussion

41.	At 88^@C benzene has a vapour pressure of 900 torr and toluene has a vapour pressure of 360 torr. What is the mole fraction of benzene in the mixture with toluene that will boil at 88^@C at 1 atm pressure, benzene toluene form an ideal solution:
Answer» 0.416 0.588 0.688 0.74 Answer :D

Discussion

42.	At 88^(@)C benzene has a vapour pressure of 900 torr and toluene has a vapour pressure of 360 torr. What is the mole fraction of benzene in the mixture with toluene that will boil at 88^(@)C at 1 atm pressure? (Consider that benzene toluene form an ideal solution):
Answer» 0.416 0.588 0.68 0.74 Answer :D

Discussion

43.	At 85°C, distilled water has [H_3O^+] concentration equal to 1 x 10^-6 molelitre. The value of K_w at this temperature will be
Answer» `110^-8` `110^-14` `110^-12` `110^-7` ANSWER :C

Discussion

44.	At 823 K and 1.0133xx 10^5 Pa, the degree of dissociation of phosgene (COCI_2)into CO and Cl_2 is 77%. Find K_p and K_c
Answer» SOLUTION :1.456, 0.0215

Discussion

45.	At 850^@Cand 1-atm pressure, a gaseous mixture of CO and CO_2in equilibrium with solid carbon is 90.55% CO by mass.C(s) + CO_2(g) iff 2CO(g)Calculate K_cfor this reaction at 850^@C .
Answer» SOLUTION :For GASSES: MOLE RATIO = PRESSURE ratio 0.153

Discussion

46.	At 817^@C, K_pfor the reaction between CO_2(g)and excess hot graphite(s) is 10 atm(a) What are equilibrium concentrations of the gases at 817^@Cand a total pressure of 5 atm(b) At what total pressure, the gas contains 5% CO_2 by volume?
Answer» SOLUTION :(a) 0.0167, 0.041 mole/L (B) 0.554 ATM

Discussion

47.	At 80^(@)C, the vapour p[ressure of pure liquid A is 520 mm of Hg and that of pure liquid B is 1000 mm of Hg. If a mixture solution of A and B boils at 80^(@)C and 1 atomoshere pressure, the amount of A in the mixture is (1 atm = 760 mm of Hg)
Answer» 60 mol precent 52 mol precent 34 mol PRESENT 48 mol precent. Solution :According to available information, `P_(A)^(@)=520 MM Hg, P_(B)^(@)=1000MM Hg` `P_(A)^(@)X_(A)+P_(B)^(@)X_(B)=760 mm Hg`. `P_(A)^(@)X_(A)+P_(B)^(@)(1-X_(A))760` `520 X_(A)+1000(1-X_(A))=760` `520X_(A)+1000-1000X_(A)=760` `-480X_(A)=-240` or `X_(A)=240/480=1/2 "or 50 mol precent".

Discussion

48.	At 80^(@)C, the vapour pressure of pure liquid 'A' is 520 mm Hg and that of pure liquid 'B' is 1000 nm Hg. If a mxiture of solution of 'A' and 'B' boils at 80^(@)C and I atm pressurc the amountof 'A' in the mixture is (1 atm =760 mm Hg)
Answer» 52 mol percelnt 34 mol percent 48 mol percent 50 mol percent Solution :At 1 atmospheric pressure the boiling point of mixture is `80^(@)C.` At boiling point the vapour pressure of mixture, `P _(tau) =1` atmosphere = 760 nm Hg. Using the RELATION, `P _(I) =P_(A)^(@)X_(A) + P_(B)^(@) X_(B), ` we GET ` P _(T) =520 X_(A) +1000 (1-X_(A))` `{P_(A)^(@)=520` mm Hg. `p _(B)^(@) =1000` mm Hg, `X_(A) + X_(B) =1}` or `760 =520 X_(A) +1000-1000 X_(A) or 480 X_(A) =240` or ` X_(A) =(240)/(480) =1/2 ` or mol percent i.e, The correct answer is

Discussion

49.	At 80^(@)C, the vapour pressure of pure liquid 'A' is 520 mm Hg and that of pure liquid 'B' is 1000 mm Hg. If a mixture of solution of 'A' and 'B' boils at 80^(@)C and 1 atm pressure, the amount of 'A' in the mixture is ( 1 atm =760 mm Hg.)
Answer» 50 mol per cent 52 mol per cent 34 mol per cent 48 mol per cent Solution :`p_("total")=p_(A)^(@)x_(A) + p_(B)^(@)x_(B)` `760=520x_(A)+1000(1-x_(A))` `760=520 x_(A)+1000-1000x_(A)` `480x_(A)=240` `x_(A)=0.5` `:.` MOLES of A `=50%`

Discussion

50.	At 80^(@)C, the vapour pressure of pure liquid 'A' is 520 mm Hg and that of pure liquid 'B' is 1000 m Hg. If a mixtuce solution of 'A' and 'B' boils at 80^(@)C and 1 atm pressure, then amount of 'A' in the mixture is (1 atm = 760 mm Hg)
Answer» 48 MOL percent 50 mol percent 52 mol percent 34 mol percent Solution :`P_("total")=(at 80^(@)C)=760mm` `P_("total")=x_(A)p_(A)^(@)+x_(B)p_(B)^(@)=x_(A)p_(A)^(@)+(1-x_(A))p_(B)^(@)` `=p_(B)^(@)+x_(A)(p_(A)^(@)-p_(B)^(@))` `THEREFORE""1000+x_(A)(520-1000)=760` `"or"480x_(A)=240` `"or"x_(A)=0.50,` i.e., 50 mol percent.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

At a given temperature if P is the vapour pressure of a solution and P_0 that of its pure solvent , the relative lowerning of vapour pressure of the solution is given by :

At a given temperature and pressure nitrogen gas is more soluble in water than Helium gas. Which one of them has higher value of K_n ?

At a given temperature and pressure nitrogen gas is more soluble in water than helium gas. Which one of them has higher value of K_(H) ?

At a given temperature ad pressure, the rate of diffusion of a gas is :

At a given tempeature, osmotic pressure of a concentrated solution of a substance ………….. .

At a fixed temperature, a liquid is in equilibrium with its vapours in a closed vessel. Which measurable quantity for the liquid gets fixed at equilibrium?

At a constant pressure the amount of heat required to raise the temperature of 1 mol of an ideal gas by 10^(@)C is x kJ. If the same increase in temperature were carried out at constant volume, then the heat required would be-

At a certain temperature, the vapour pressure( in mm Hg) of CH_(3)OH and C_(2)H_(5)OH solutionis representedbyP = 119 x + 135 where x is themolefractionof CH_(3)OH . Whatare thevapour pressureof pure componentsat thistemperature ?

At a certain temperature, the solubility of the salt M_(m)A_(n)in water is s moles per litre. The solubility product of the salt is :

At a certain temperature the time required for the complete diffusion of 200 mL of H_(2) gas is 30 minutes. The time required for the complete diffusion of 50 mL of O_(2) gas at the same temperature will be

At a certain temperature, the value of the slope of the plot of osmotic pressure (pi) against concentration ("C in mol L"^(-1)) of a certain polymer solution is 291R. The temperature at which osmotic pressure is measured is (R is gas constant)

At a certain temperature, the half life period for the catalytic decomposition of ammonia was found as follows: Calculate order of the reaction.

At a certain temperature, the reaction PCl_(5)(g)hArrPCl_(3)(g) + Cl_(2)(g) has an equilibrium constant K_(c) = 5.8 ×x 10^(-2). Calculate the equilibrium concentrations of PCl_(5), PCl_(3) and Cl_(2) if only PCl_(5) is present initially, at a concentration of 0.160 M.

At a certain temperature the dissocation constants of formic acid and acetic acid are 1.8xx10^(-4) and 1.8xx10^(-6) respectively. The concentration of acetic acid solution in which the hydrogen ion has the same concentration as in 0.001 M formic acid solution is equal to

At a certain temperature T, the endothermic reactiion ArarrB proceeds almost to completion. The entropy change is:

At a certain temperature pure liq. A & liq B have vapour pressure 10 torr and 37 torr respectively. For a certain ideal Solution of A, B the Vapour is equilibrium with the liquid . Molefraction of A in the solution is 0.346. The (P_(B))/(P_(A)) in the solution is .

At a certain temperature, K_(sp) of AgCl in water is 1.8xx10^(-10). What will be its K_(sp) is a 0.1 M solution of AgNO_(3) at some temperature.

At a certain temperature K_(w) is 9.55xx10^(-14). The pH of water at this temperature is :

At a certain temperature for which RT=25 lit.atm. "mol"^(-1)., the density of a gas, in gas lit^(-1), is d=2.00 P+0.020 P^2, where P is the pressure in atmosphere.The molecular weight of the gas in gm "mol"^(-1) is

At a certain temperature equilibrium constant (K_c) is 16 for the reaction. SO_2(g)+NO_2(g) hArr SO_3(g) +NO_((g)) if we take one mole each of the four gases in one litre container, what would be the equilibrium concentration of NO and NO_2?

At a certain temperature and at infinite dilution, the equivalent conductances of sodium benzoate, hydrochloric acid and sodium chloride are 240, 349 and 229ohm^(-1) cm^(2) equiv^(-1) respectively. The equivalent conductance of benzoic acid inohm^(-1) cm^(2) equiv^(-1) at the same conditions is

At a certain temperature and a total pressure of 10^(5) Pa, iodine vapours contain 40% by volume of iodine atoms.I_(2)(g) hArr 2I(g)K_(p) for the equilibrium reaction is :

At a certain temperature , 2HI ⇌ H_2 + I_2 on 50 % HIis dissolved at equilibrium .What the value of equilibrium constant ?

At a certain temperature and a total pressure of 10^(5) Pa, iodine vapours contain 40% by volume of iodine atoms [I_(2(g))iff2I_((g))]. K_(p) for the equilibrium will be

At a certain temp. HIhArrH_(2)+I_(2) only 50% HI is dissociated at equilibrium. The equiliium constant is

At 945^@C and 1 atm, 1.7 g of H_2Soccupies a volume of 5.384 litres. Calculate thedegree of dissociation of hydrogen sulphide if the reaction proceeds according to the equation H_2S= H_2 + 0.5 S_2(v)

At a certain instant a piece of radioactive material contains 10^(12) atoms. The half-life of the material is 30 days. What will be number of distingrations per second of the sample at that instant?

At a certain Hill station, water boils at 96^(@)C. The amount of NaCl that should be added to one litre of water so that it boils at 100^(@)C will be (K_(b) for H_(2)O=0.52K//m)

At a boiling point of pure solvent ,solution will not boil because

At 90^@C, the vapour pressure of toluene is 400 torr and that ofsigma-xylene is 150 torr. What is the composition of the liquid mixture that boils at 90^@C, when the pressure is 0.50 atm? What is the composition of vapour produced?

At 90^(@)C, the vapour pressure of toluene is 400 mm and that of xylene is 150 mm. What is the composition of the liquid mixture that will boil at 90^(@)C when the pressure of mixture is 0.5 atm?

At 90^(@)C, pure water has [H_(3)O^(+)]=10^(-6)mol L^(-).The value of K_(w) at 90^(@)Cis:

At 90^(@)C pure water has [H_(3)O^(+)] = 10^(-6) M, the value of K_(w) at this temperature will be

At 90^@C pure water has [H_3O^+] = 10^-6 mol/ litre. The value of K_w at 90^@C is:

At 90^(@) C,pH of an aq . Solution of a strong electrolyte is 7 . What is the nature of electrolyte ?

At 88^(o)C benzene has a vapour pressure of 900 torr and toluene has a vapour pressure of 360 torr. What is the mole fraction fo benzene in the mixture with toluene that will boil at 88^(o)C at 1 atm pressure, benzene-toluene from an ideal solution ? (P of mixture = 760 torr)

At 88^(@)C benzene has a vapour pressure of 900 torr and toluene has vapour pressure of 360 torr. What is the mole fraction of benzene in the mixture with toluene that will be boil at 88^(@)C at 1 atm pressure, benzene- toluene form an idean solution.

At 88^@C benzene has a vapour pressure of 900 torr and toluene has a vapour pressure of 360 torr. What is the mole fraction of benzene in the mixture with toluene that will boil at 88^@C at 1 atm pressure, benzene toluene form an ideal solution:

At 88^(@)C benzene has a vapour pressure of 900 torr and toluene has a vapour pressure of 360 torr. What is the mole fraction of benzene in the mixture with toluene that will boil at 88^(@)C at 1 atm pressure? (Consider that benzene toluene form an ideal solution):

At 85°C, distilled water has [H_3O^+] concentration equal to 1 x 10^-6 molelitre. The value of K_w at this temperature will be

At 823 K and 1.0133xx 10^5 Pa, the degree of dissociation of phosgene (COCI_2)into CO and Cl_2 is 77%. Find K_p and K_c

At 850^@Cand 1-atm pressure, a gaseous mixture of CO and CO_2in equilibrium with solid carbon is 90.55% CO by mass.C(s) + CO_2(g) iff 2CO(g)Calculate K_cfor this reaction at 850^@C .

At 817^@C, K_pfor the reaction between CO_2(g)and excess hot graphite(s) is 10 atm(a) What are equilibrium concentrations of the gases at 817^@Cand a total pressure of 5 atm(b) At what total pressure, the gas contains 5% CO_2 by volume?

At 80^(@)C, the vapour p[ressure of pure liquid A is 520 mm of Hg and that of pure liquid B is 1000 mm of Hg. If a mixture solution of A and B boils at 80^(@)C and 1 atomoshere pressure, the amount of A in the mixture is (1 atm = 760 mm of Hg)

At 80^(@)C, the vapour pressure of pure liquid 'A' is 520 mm Hg and that of pure liquid 'B' is 1000 nm Hg. If a mxiture of solution of 'A' and 'B' boils at 80^(@)C and I atm pressurc the amountof 'A' in the mixture is (1 atm =760 mm Hg)

At 80^(@)C, the vapour pressure of pure liquid 'A' is 520 mm Hg and that of pure liquid 'B' is 1000 mm Hg. If a mixture of solution of 'A' and 'B' boils at 80^(@)C and 1 atm pressure, the amount of 'A' in the mixture is ( 1 atm =760 mm Hg.)

At 80^(@)C, the vapour pressure of pure liquid 'A' is 520 mm Hg and that of pure liquid 'B' is 1000 m Hg. If a mixtuce solution of 'A' and 'B' boils at 80^(@)C and 1 atm pressure, then amount of 'A' in the mixture is (1 atm = 760 mm Hg)