94420 + Interview Questions in Chemistry in Class 12

1.	For reaction : A+2Bunderset("yield")overset(40%)rarr4C If 10 moles of A and B each are taken calculate number of moles of 'C' formed are:
Answer» 20 4 16 8 Solution :`A+2Brarr4C` 10 10 B is LR which is 40% react `0.4xxn_(B)=(n_(C)"formed")/(2)RARR n_(C)"formed"=0.4xx10xx2=8` Ans

Discussion

2.	For reaction 2NOCl_((g))hArr2NO_((g))+Xl_(2(g)), K_(c)at 427^(@)Cis 3xx10^(-6)Lmol^(-1). The value of K_(p) is nearly
Answer» <P>`7.50xx10^(-50)` `2.50xx10^(-50)` `2.50xx10^(-4)` `1.72xx10^(-4)` Solution :`2NOCl_((G))=2NO_((g))+Cl_(2(g))` `K_(p)+K_(c)(RT)^(DELTAN)` `K_(p)=3xx10^(-6)(0.0821xx700)=172.41xx10^(-6)=1.72xx10^(-4)`

Discussion

3.	For reaction , 3A toproducts, it is found that the rate of reaction increases 4- fold when concentration of A is increased 16 times keeping the temperature constant. The order of reaction is
Answer» `2` `1` `1` `0.5` ANSWER :D

Discussion

4.	For reaction, 2A_((g))hArr3C_((g))+D_((s)), the value of K_(c) will be equal to
Answer» `K_(p)(RT)` `K_(p)//RT` `K_(p)` None of these Solution :`2A_((g))hArr3C_((g))+D_((s))` For this reaction, `Deltan_(g)=3-2=1` `THEREFORE K_(p)=K_(C)[RT]^(1)or (K_(p))/(K_(c))=RTor K_(c)=(K_(p))/(RT)`

Discussion

5.	For reaction 2Cl(s)rarrCl_(2)(s), the signs of DeltaH and DeltaSrespectively are
Answer» `+, -` `+, +` `-, -` `-, +` SOLUTION :Because SOLID `RARR` solid, `DELTAS` is same and `DELTAH` is -ve.

Discussion

6.	For radioactive decay:
Answer» `t_(3//4) = 2 t_(1//2)` `t_(7//8) = 3 t_(1//2)` `t_(99%) = 2 t_(90%)` `t_(90%) = (10)/(3) t_(50%)` ANSWER :a,B,C,d

Discussion

7.	For raction : mA+nB rarr pC+ qDthe rate law given by dx/dt = K[A]^x[B]^y The correct statement for this raction if
Answer» the molecularityh of the raction is m+n the overall order of the raction is m + n both are correct none of corrcet Solution :For the reaction `m A+ n B to p C + q D ` , the rate law , `(dx)/(DT) = k [A]^(x) xx [B]^(y)` Molecularity of the reaction = Total NUMBER of reactant molecules in the reactant molecules in the reaction = m+ n Order of the reaction = SUM of the powers of the conc. of reactants in the rate law = x+ y

Discussion

8.	For Ra^(266 t_((t)/(2))) yrs is 1620 yrs from 0.001 g of Ra how many alpha particles relaease per min?
Answer» SOLUTION :`2.17xx10^(9) MIN ^(-1)`

Discussion

9.	For pure water on small increase in temperature:
Answer» PH decreases POH decreases pH increases pOH increases ANSWER :a,B

Discussion

10.	For production of steel ________ is used .
Answer» AOP BOP COP DOP Solution :BOP-basic OXYGEN PROCESS

Discussion

11.	For producing the effective collisions the colliding molecules must have
Answer» a certain MINIMUM AMOUNT of energy energy equal to or greater than THRESHOLD energy proper orientation both threshold energy and proper orientation Answer :D

Discussion

12.	For producing the effective collisions thecolliding molecules must have :
Answer» A CERTAIN MINIMUM amount of energy Energy lesser than threshold energy Improper ORIENTATION Proper orientation and energy equal or greater than threshold energy Answer :D

Discussion

13.	For prevention of rusting of iron,which is used in paints
Answer» PbO `PbO_(2)` `Pb_(3)O_(4)` `PbSO_(4)` ANSWER :C

Discussion

14.	For preparing one litre N/10 solution of H_(2)SO_(4), we need H_(2)SO_(4)
Answer» 98 gms 10 gms 100 gms 4.9 gms Solution :`(1)/(10)=(Wxx1000)/(EQ." "wtxxvol.)=(Wxx1000)/(49xx1000)impliesW=4.9gm`

Discussion

15.	For prevention of rusting of iron, which is used in paints ?
Answer» PBO `PbO_2` `Pb_3O_4` `PbSO_4` SOLUTION :`Pb_3O_4`

Discussion

16.	For preparing monohalogen derivative of phenol, halogenation is carried out
Answer» at HIGH temperature at LOW temperature inpresence of non-polar solvents both 'B' and 'c Answer :D

Discussion

17.	For preparing methyl acetylene, we take -
Answer» `CH_(3)-UNDERSET(CHCOOK)underset(\|\|)(C)-COOK` `underset(CHCOOK)OVERSET(CHCOOK)(\|\|)` `CH_(3)-CH_(2)-underset(CHCOOK)underset(\|\|)(C COOK)` All of these Answer :A

Discussion

18.	For preparing M/10 solution of H_2 SO_4 in one litre we need H_2 SO_4
Answer» 0.009 g 49.0 g 4.8 g 9.8 g Answer :D

Discussion

19.	For preparing H_(2)O_(2)in the laboratory
Answer» `PbO_(2)`is added to ACIDIFIED solution of `KMnO_(4)` `BaO_(2)` is added to `CO_(2)`bubbling through cold water `MnO_(2)`is added to dilute cold `H_(2)SO_(4)` `Na_(2)O_(2)`is added to BOILING water Solution :`BaO_(2)+H_(2)O+CO_(2)rarr BaCO_(3)+H_(2)O_(2)`

Discussion

20.	For preparing a salt bridge, gelatin or agar-agar is dissolved in a hot aqueous solution of
Answer» `K_(2)CO_(3)` `K_(2)SO_(4)` `NH_(4)NO_(3)` `(NH_(4))_(3)PO_(4)` ANSWER :C

Discussion

21.	For preparing an alkane, a saturated solution of sodium or potassium salt of a carboxylic acid is subjected to
Answer» Hydrolysis Oxidation Hydrogenation Electrolysis Solution :ALKANES are prepared from carboxylic ACIDS byelectrolysis. In electrolysis , and AQUEOUS solution of sodium or potassium salt of carboxylic ACID is electrolysed and alkane is evolved at the anode (Kolbe's electrolysis)

Discussion

22.	For preparing a buffer solution of pH 6 by mixing sodium acetate and acetic acid, the ratio of the concentration of salt and acid should be (K_(a) = 10^(-5))
Answer» `1:10` `10:1` `100:1` `1:100` SOLUTION :`K_(a) = 10^(-5) , PH = 6` `pH = -LOG K_(a) + log .(["SALT"])/(["Acid"]), 6 = -log 10^(-5) + log .(["Salt"])/(["Acid"])` `6 = 5 log 10 + log .(["Salt"])/(["Acid"]), 6 = 5 + log .(["Salt"])/(["Acid"])` `log .(["Salt"])/(["Acid"]) = 6 =5 = 1, (["Salt"])/(["Acid"]) = (10)/(1)`.

Discussion

23.	For preparing 0.1 N solution of a compound fromits impure sample of which the percentage purity is known, the weight of the substance required will be
Answer» More than the theroretical WEIGHT LESS than the THEORETICAL weight Same as the throretical weight None of these Answer :A

Discussion

24.	For preparing a buffer solution of pH 6 BY mixing sodium acetate and acetic acid the ratio of concentration of salt and acid (K_a=10^(-5))Should be :
Answer» 1:10 10:1 100:1 1:100 Answer :B

Discussion

25.	For preparing 0.1 N solution of a compound from its impure sample, of which the percentage purity is known, the weight of the substance required will be
Answer» More than the THEORETICAL weight Less than the theoretical weight Same as theoretical weight None of these Answer :A

Discussion

26.	For precipitation reaction of Ag^(+) ions with NaCl, which of the following statements is correct
Answer» `DELTAH` for the reaction is ZERO `DeltaG` for the reaction is zero `DeltaG` for the reaction is NEGATIVE `[DeltaG]=[DeltaH]` Solution :Because the reaction is SPONTANEOUS.

Discussion

27.	For precipitation of silver from the complex [Ag(CN)_(2) ]^(-), zinc is used but not copper. Why?
Answer» Solution :copper is ALSO more electropositive than SILVER. Thuspractically copper can also precipitatesilver from`[Ag (CN)_(2)]^(-)`. ButZincis more electropositivewhencompared with copper and ZINC is cheaper than copper . Thus zincis USED commonly to precipitate silver from `[Ag(CN)_(2)]^(-)`

Discussion

28.	For positive sol arrange the coagulation power of the following active ions in the decreasing order, Cl-, PO_(4)^(3-), [Fe(CN)_(6)]^(4-), SO_(4)^(2-)
Answer» SOLUTION :Decreasing ORDER : `[Fe(CN)_(6)]^(4-) gt PO_(4)^(3-) gt SO_(4)^(2-) gt Cl^(-)`

Discussion

29.	For per gram of reactant, the maximum quantity of N_(2) gas is produced in which of the following thermal decomposition reactions? (Given : Atomic wt. - Cr = 52u, Ba = 137u)
Answer» `2NH_(4)NO_(3)(s) to 2N_(2)(g) + 4H_(2)O(g)+O_(2)(g)` `BA (N_(3))_(2)(S) to Ba(s) + 3N_(2)(g)` `(NH_(4))_(2)Cr_(2)O_(7)(s) to N_(2)(g) + 4H_(2)O(g)` `2NH_(3)(g) to N_(2)(g) + 3H_(2)(g)` Answer :D

Discussion

30.	For per gram of reactant, the maximum quantity of N_(2) gas is produce in which of the following thermal decomposition reactions ? (Given : Atomic wt : Cr = 52 u, Ba = 137 u)
Answer» `(NH_(4))_(2) Cr_(2)O_(7) (s) rarr N_(2)(g) + 4H_(2) O (g) + Cr_(2)O_(3) (s)` `2NH_(4)NO_(3) (s) rarr 2N_(2) (g) + 4H_(2) O (g) + O_(2) (g)` `Ba(N_(3))_(2) (s) rarr Ba (s) + 3N_(2) (g)` `2NH_(3) (g) rarr N_(2) (g) + 3H_(2) (g)` ANSWER :D

Discussion

31.	For PCl_5 hArr PCl_3 + Cl_2, DeltaH = 22 kcal the dissociation of PCl_5 will be more on:
Answer» INCREASING temperature Decreasing pressure Increasing pressure Increasing the CONCENTRATION of chlorine Answer :A

Discussion

32.	for oxyacid HClO_(x), if x=y=z (x,y and are natural numbers), then calculate the value of \|x+y+z\|. Where x= Number of 'O' atoms y= Total number of Ione pair at central atom z= Total number of pi (pi) electrons in the oxyacid
Answer» SOLUTION :6 The COMPOUND is `HCIO_(3)`

Discussion

33.	For oxidation of iron, 4Fe(s) + 3O2(g) to 2Fe2O3(s) entropy change is – 549.4 JK ^(–1 ) mol^(–1)at 298K. Deltar H^(@) for this reaction is – 1648 xx 10^( 3) J mol^(–1)Above reaction is :-
Answer» Spontaneous Non-spontaneous At equilibrium Cant predict SOLUTION :`Delta G =Delta H – T.DeltaS `

Discussion

34.	For osazone formation, the effective structural unit necessary is
Answer» `UNDERSET(\|)underset(CO)underset(\|)(""CH_2OCH_3)` `underset(\|)underset(CO)underset(\|)(""CH_2OH)` `underset(\|)underset(""CHOCH_3)underset\|(""CH_2OH)` `underset\|underset(""CHOCH_3)underset\|(""CHO)` ANSWER :B

Discussion

35.	For ......... ores froth floatation process is used.
Answer» BAUXITE Cinnabar Haematite Horn SILVER Answer :B

Discussion

36.	For one of the element various successive ionization enthalpy (in kJ "mol"^(-1) ) are given below: The element is
Answer» Al Si Mg P Answer :A

Discussion

37.	For one of the element varioussuccessiveionizationethalpies ( in kj "mol"^(-1)) are givenbelow : The elementis
Answer» A) P B) Mg C) Si D) Al Solution :LARGE jump between `IE_(3)` and `IE_(4)` suggest that the element has three valence electrons.

Discussion

38.	For one mole of NaCl(s) the lattice enthalpy is : Na(s) + (1)/(2)Cl_(2)(g) overset(+108.4 kJ//mol)rarr Na(g) + (1)/(2)Cl_(2)(g) overset(+495.6 kJ//mol)rarr Na^(+)(g) + (1)/(2)Cl_(2)(g) overset(121 kJ//mol)rarr Na^(+)(g) + Cl(g) overset(-348.6 kJ//mol)rarr Na^(+)(g) + Cl^(-)(g) overset(Delta H^(theta)" lattice")rarr NaCl("solid") underset(-411.2 kJ/mol)larr Na(s) + (1)/(2)Cl_(2)(g)
Answer» `- 788 KJ//mol` `+ 878 kJ//mol` `+ 788 kJ//mol` `- 878 kJ//mol` Solution :`Delta_(f) H = - 411.2 kJ mol^(-1)` `- 411.2 = 108.4 + 495.6 + 121 - 348.2 + Delta H_("LATTICE")^(@)` :. `Delta H_("lattice")^(@) = - 411.2 - 108.4 - 495.6 - 121 + 348.2` `= - 788 kJ mol^(-1)`

Discussion

39.	For one of the element various successive ionization enthalpies (in kJ mol^(-1)) are given below : The element is
Answer» `Mg` `AL` `P` `Si` Solution :LARGE jump between `IE_3 and IE_4` suggests that the element has THREE VALENCE electorns.

Discussion

40.	For one molecule reaction at higher pressure or higher concentration what is order of reactant?
Answer» 0 1 `1(1)/(2)` 2 Solution :The order of ONE molecule reaction is 1.

Discussion

41.	For one mole of glycerol, how many mole of acetyl chloride are required for complete acetylation:
Answer» One Two Three Four Answer :C

Discussion

42.	For one mole of an ideal gas the slope of V vs. T curve at constant pressure of 2 atm is X lit "mol"^(-1)K^(-1). The value of the ideal universal gas constant R in termsof X is
Answer» X lit ATM `"mol"^(-1)K^(-)` X/2 lit atom `"mol"^(-1)K^(-1)` 2X lit atm `"mol"^(-1)K^(-1)` 2X atm `"lit"^(-1)"mol"^(-1)K^(-1)` Solution :We can TAKE T to be the independent variable and V tobe the dependent variable. Now, for ONE mole of an ideal GAS , `PV=RT` `impliesV/T=R/Pimplies` slope `=R/P=X` lit `"mol"^(-1)K^(-1)` `impliesR=PxxX` lit `"mol"^(-1)K^(-1)` `R=23` atm `xx X` lit `"mol"^(-1)K^(-)` ( `:. P=2` atm) `impliesR=2` X lit atm `"mol"(-1)K^(-1)`

Discussion

43.	For one mole of electrolyte which of the following increases with dilution?
Answer» Resistance Specofic conductance Molar conductance None of these Answer :C

Discussion

44.	For one mole of an ideal gas, increasing the temperature from 10^(@)C to 20^(@)C
Answer» A) increases the average kinetic energy by TWO TIMES. B) increases the rms velocity by `sqrt(2)` times C) increases the rms velocity by two times D) increases both the average kinetic energy and rms velocity, but not significantly. Solution :Initial temperature `=283K` Final temperature `=293K` `KE_(1)=(3RT_(1))/(2),KE_(2)=(3RT_(2))/(2)` `(KE_(1))/(KE_(2))=(T_(1))/(T_(2))=(283)/(293)=0.96` `KE_(2)=1.04KE_(1)` `v_(rms)=sqrt((3RT)/(M))` `(v_(1))/(v_(2))=sqrt((T_(1))/(T_(2)))rArrsqrt((283)/(293))` `v_(2)=v_(1)sqrt((293)/(283))=1.02v_(1)` Both average K.E. and rms velocity increase but not significantly.

Discussion

45.	For one mole of an ideal gas ((delta P)/(delta T))_(V) ((delta V)/(delta T))_(P) ((delta V)/(delta P))_(T)=
Answer» `-1` `(R^(2))/(P^(2))` `(R^(2))/(P^(2))` `+1` Answer :A::B::C

Discussion

46.	For one mole of a van der Waal's gas when b = 0 and T = 300K, the PV us 1//V plot is shown ahead. The value of the van der Waal's constant a(atm. "litre"^(2) mol^(-2)) is:
Answer» `1.0` `4.5` `1.5` `3.0` ANSWER :C

Discussion

47.	For one mole of a gas, the total kinetic energy is equal to :
Answer» RT `(3)/(2) RT` `( 2)/( 3) RT` `( 3)/( 2) ( RT)/( N_(0))` Answer :B

Discussion

48.	For one first order reaction 60 minutes are required to decrease the initial concentration from 0.8 M to 0.1 M,determine the half reaction time (t_((1)/(2)))
Answer» 20 min 30 min 40 min 15 min Answer :A

Discussion

49.	For O_(2) gas at T_(1) and T_(2) following Maxwell speed distribution is observed [not to be scale] Ratio A_(1)//A_(2) is equal to
Answer» ANSWER :1

Discussion

50.	For O_3(g) + OH(g)iffH(g) + 2O_2(g), K=0.096 at 298 K and K=1.4 at 373 K. Above what temperature will the reaction become thermodynamically spontaneous?
Answer» SOLUTION : For spontaneous process `K_p GT 1` `T gt 361 K`

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

For reaction : A+2Bunderset("yield")overset(40%)rarr4C If 10 moles of A and B each are taken calculate number of moles of 'C' formed are:

For reaction 2NOCl_((g))hArr2NO_((g))+Xl_(2(g)), K_(c)at 427^(@)Cis 3xx10^(-6)Lmol^(-1). The value of K_(p) is nearly

For reaction , 3A toproducts, it is found that the rate of reaction increases 4- fold when concentration of A is increased 16 times keeping the temperature constant. The order of reaction is

For reaction, 2A_((g))hArr3C_((g))+D_((s)), the value of K_(c) will be equal to

For reaction 2Cl(s)rarrCl_(2)(s), the signs of DeltaH and DeltaSrespectively are

For radioactive decay:

For raction : mA+nB rarr pC+ qDthe rate law given by dx/dt = K[A]^x[B]^y The correct statement for this raction if

For Ra^(266 t_((t)/(2))) yrs is 1620 yrs from 0.001 g of Ra how many alpha particles relaease per min?

For pure water on small increase in temperature:

For production of steel ________ is used .

For producing the effective collisions the colliding molecules must have

For producing the effective collisions thecolliding molecules must have :

For prevention of rusting of iron,which is used in paints

For preparing one litre N/10 solution of H_(2)SO_(4), we need H_(2)SO_(4)

For prevention of rusting of iron, which is used in paints ?

For preparing monohalogen derivative of phenol, halogenation is carried out

For preparing methyl acetylene, we take -

For preparing M/10 solution of H_2 SO_4 in one litre we need H_2 SO_4

For preparing H_(2)O_(2)in the laboratory

For preparing a salt bridge, gelatin or agar-agar is dissolved in a hot aqueous solution of

For preparing an alkane, a saturated solution of sodium or potassium salt of a carboxylic acid is subjected to

For preparing a buffer solution of pH 6 by mixing sodium acetate and acetic acid, the ratio of the concentration of salt and acid should be (K_(a) = 10^(-5))

For preparing 0.1 N solution of a compound fromits impure sample of which the percentage purity is known, the weight of the substance required will be

For preparing a buffer solution of pH 6 BY mixing sodium acetate and acetic acid the ratio of concentration of salt and acid (K_a=10^(-5))Should be :

For preparing 0.1 N solution of a compound from its impure sample, of which the percentage purity is known, the weight of the substance required will be

For precipitation reaction of Ag^(+) ions with NaCl, which of the following statements is correct

For precipitation of silver from the complex [Ag(CN)_(2) ]^(-), zinc is used but not copper. Why?

For positive sol arrange the coagulation power of the following active ions in the decreasing order, Cl-, PO_(4)^(3-), [Fe(CN)_(6)]^(4-), SO_(4)^(2-)

For per gram of reactant, the maximum quantity of N_(2) gas is produced in which of the following thermal decomposition reactions? (Given : Atomic wt. - Cr = 52u, Ba = 137u)

For per gram of reactant, the maximum quantity of N_(2) gas is produce in which of the following thermal decomposition reactions ? (Given : Atomic wt : Cr = 52 u, Ba = 137 u)

For PCl_5 hArr PCl_3 + Cl_2, DeltaH = 22 kcal the dissociation of PCl_5 will be more on:

for oxyacid HClO_(x), if x=y=z (x,y and are natural numbers), then calculate the value of |x+y+z|. Where x= Number of 'O' atoms y= Total number of Ione pair at central atom z= Total number of pi (pi) electrons in the oxyacid

For oxidation of iron, 4Fe(s) + 3O2(g) to 2Fe2O3(s) entropy change is – 549.4 JK​ ^(–1 ) ​mol^(​–1)at 298K. Deltar H^(@) for this reaction is – 1648 xx 10​^( 3)​ J mol^(​–1)Above reaction is :-

For osazone formation, the effective structural unit necessary is

For ......... ores froth floatation process is used.

For one of the element various successive ionization enthalpy (in kJ "mol"^(-1) ) are given below: The element is

For one of the element varioussuccessiveionizationethalpies ( in kj "mol"^(-1)) are givenbelow : The elementis

For one of the element various successive ionization enthalpies (in kJ mol^(-1)) are given below : The element is

For one molecule reaction at higher pressure or higher concentration what is order of reactant?

For one mole of glycerol, how many mole of acetyl chloride are required for complete acetylation:

For one mole of an ideal gas the slope of V vs. T curve at constant pressure of 2 atm is X lit "mol"^(-1)K^(-1). The value of the ideal universal gas constant R in termsof X is

For one mole of electrolyte which of the following increases with dilution?

For one mole of an ideal gas, increasing the temperature from 10^(@)C to 20^(@)C

For one mole of an ideal gas ((delta P)/(delta T))_(V) ((delta V)/(delta T))_(P) ((delta V)/(delta P))_(T)=

For one mole of a van der Waal's gas when b = 0 and T = 300K, the PV us 1//V plot is shown ahead. The value of the van der Waal's constant a(atm. "litre"^(2) mol^(-2)) is:

For one mole of a gas, the total kinetic energy is equal to :

For one first order reaction 60 minutes are required to decrease the initial concentration from 0.8 M to 0.1 M,determine the half reaction time (t_((1)/(2)))

For O_(2) gas at T_(1) and T_(2) following Maxwell speed distribution is observed [not to be scale] Ratio A_(1)//A_(2) is equal to

For O_3(g) + OH(g)iffH(g) + 2O_2(g), K=0.096 at 298 K and K=1.4 at 373 K. Above what temperature will the reaction become thermodynamically spontaneous?

For oxidation of iron, 4Fe(s) + 3O2(g) to 2Fe2O3(s) entropy change is – 549.4 JK ^(–1 ) mol^(–1)at 298K. Deltar H^(@) for this reaction is – 1648 xx 10^( 3) J mol^(–1)Above reaction is :-