94420 + Interview Questions in Chemistry in Class 12

1.	In coordination chemistry there are a variety of methods applied to find out the structure of complexes.One method involves treating the complex with known reagents and from the nature of reaction, the formula of the complex can be predicted.An isomer of the complex Co(en)_2(H_2O)Cl_2Br,on reaction with concentrated H_2SO_4 (dehydrating agent) it suffers loss in weight and on reaction with AgNO_3 solution it gives a white precipitate which is soluble in NH_3(aq). If all the ligands in the coordination sphere of the above complex be replaced by F^(bar), then the magnetic moment of the complex ion (due to spin only) will be :
Answer» 2.8 BM 5.9 BM 4.9 BM 1.73 BM Solution :With `F^(-)` ligand, metal ION has ELECTRON CONFIGURATION , `t_(2G)^(2,1,1)e_(g)^(1.1)` So, `mu=sqrt(4(4+2))~~4.9` B.M , where n=number of unpaired ELECTRONS

Discussion

2.	In coordination chemistry there are a variety of methods applied to find out the structure of complexes.One method involves treating the complex with known reagents and from the nature of reaction, the formula of the complex can be predicted.An isomer of the complex Co(en)_2(H_2O)Cl_2Br,on reaction with concentrated H_2SO_4 (dehydrating agent) it suffers loss in weight and on reaction with AgNO_3 solution it gives a white precipitate which is soluble in NH_3(aq). The correct formula of the complex is :
Answer» `[CoClBr(en)_2] H_2O` `[CoCl(en)_2 (H_2O)]BrCl` `[CO Br(en)_2 (H_2O)]Cl_2` `[CoBrCl(en)_2]Cl. H_2O` Solution :Water present in IONISATION sphere is absorbed by conc. `H_2SO_4`(dehydrating agent).If `Cl^(-)` present as counter ION then reacts with `AgNO_3` to GIVE WHITE precipitate of AgCl

Discussion

3.	In coordination chemistry there are a variety of methods applied to find out the structure of complexes. One method involves treating the complex with known reagents and from the nature of raction, the formula of the complex can be predicted. An isomer of the complex Co(en)_(2)(H_(2)O)Cl_(2)Br, on reaction with concentrated H_(2)SO_(4) (dehydrating agent), suffers loss in weight and on reaction with AgNO_(3) solution it gives a white precipitate which is soluble in NH_(3)(aq). Similarly if all the ligands in the coordination sphere br replaced by NO_(2)^(-), then the magnetic moment of the complex ion (due to spin only) will be :
Answer» 1.73 BM 0.0 BM 4.9 BM 5.9 BM Solution :`[Co(NO_(2))_(6)]^(3-) d^(6)` (SPIN PAIRED) DIAMAGNETIC.

Discussion

4.	In coordination chemistry there are a variety of methods applied to find out the structure of complexes. One method involves treating the complex with known reagents and from the nature of raction, the formula of the complex can be predicted. An isomer of the complex Co(en)_(2)(H_(2)O)Cl_(2)Br, on reaction with concentrated H_(2)SO_(4) (dehydrating agent), suffers loss in weight and on reaction with AgNO_(3) solution it gives a white precipitate which is soluble in NH_(3)(aq). If all the ligands in the coordination sphere of the above complex be replaced by F^(-), then the magnetic moment of the complex ion (due to spin only) will be :
Answer» 2.8 BM 5.9 BM 4.9 BM 1.73 BM Solution :`[CoF_(6)]^(3-) d^(6)` (spin free) 4 unpaired electron.

Discussion

5.	In coordination chemistry there are a variety of methods applied to find out the structure of complexes. One method involves treating the complex with known reagents and from the nature of raction, the formula of the complex can be predicted. An isomer of the complex Co(en)_(2)(H_(2)O)Cl_(2)Br, on reaction with concentrated H_(2)SO_(4) (dehydrating agent), suffers loss in weight and on reaction with AgNO_(3) solution it gives a white precipitate which is soluble in NH_(3)(aq). The correct formula of the complex is :
Answer» `[CoClBr(EN)_(2)]H_(2)O` `[COCL(en)_(2)(H_(2)O)]BrCl` `[CoBr(en)_(2)(H_(2)O)]Cl_(2)` `[CoBrCl(en)_(2)]Cl.H_(2)O` SOLUTION :`[CoBrCl(en)_(2)]Cl.H_(2)O` satisfies both conditions.

Discussion

6.	In conversion of lime-stone to lime, CaCO_(3)(s)toCaO(s)+CO_(2)(g) the value of DeltaH^(@)andDeltaS^(@)" are "+179.1KJmol^(-1) and 160.2 J/K respectively at 298 K and 1 bar. Assuming that DeltaH^(@)andDeltaS^(@) do not change with temperature, temperature above which conversion of limestone to lime will be spontaneous is -
Answer» 1008 K 1200 K 845 K 1118 K Answer :D

Discussion

7.	In conversion of lime-stone to lime CaCO_(3)(s) rarrCaO(s)+CO_(2)(g)the values of DeltaH^(@) and DeltaS^(@) are +179.1 kJ mol^(-1) and 160.2 J/K respectively at 298 K and 1 bar. Assuming that DeltaH^(@) do not change with temperature, temperatureabove which conversion of limestone to lime will be spontaneous is
Answer» 1008 K 1200 845 K 1118 K Solution :We know, `DeltaG=DeltaH-TDeltaS` So, LETS find the equilibrium TEMPERATURE, i.e. at which `DeltaG=0, DeltaH-TDeltaS` `T=(179.1xx1000)/(160.2)=1118 K` So, at temperature above this, the REACTION will BECOME SPONTANEOUS.

Discussion

8.	In conversion of 2-butanone to propanoic acid which reagent is used
Answer» `NAOH,NaI//H^(o+)` Fehling SOLUTION `NaOH,I_(2)//H^(o+)` TOLLEN's reagent ANSWER :C

Discussion

9.	In countries nearer to polar region, the roads are sprinkled with CaCl_(2). This is
Answer» to MINIMISE the snow fall to minimise pollution to minimise the accumulation of DUST on the road to minimise the wear and tear of the roads. Solution :`CaCl_(2)` acts as a non volatile solute and results in depression in freezing point. THUS, snow fall is reduced and prevents BLOCKING of roads in the POLAR region.

Discussion

10.	In conversion of 2-butanone to propanoic acid when reagent is used.
Answer» `NaOH, NaI//H^(o+)` FEHLING solution `NaOH, I_(2)//H^(o+)` Tollen's reagent Solution :`CH_(3)-UNDERSET(O)underset(\|\|)(C )-CH_(2)-CH_(3)OVERSET(I_(2))rarrCl_(3)-underset(O)underset(\|\|)(C )-CH_(2)-CH_(3)overset(OH^(Θ))rarr CHI_(3)+CH_(3)-CH_(2)-underset(O)underset(\|\|)(C )-O^(-)` ,

Discussion

11.	In contextof the lanthanoids , which of the followingstatements is not correct ?
Answer» All the members exhibit `+3` oxidation state Because similar properties, the separation of lanthanoids is not easy. Availability of 4f ELECTRONS results in the formation of compounds in `+4` state forall the members of the series. There is a GRADUAL decrease in the radii of the members with increasing atomic NUMBER in the series Solution :Availabilityof 4f electrons does not result in the formation of compounds in `+4`oxidation statefor all the members of the langthanoid series.

Discussion

12.	In continuous etherification process 1^(st)step is
Answer» FORMATION of carbocation protonation of alcohol loss of PROTON from oxocation cleavage of O-H BOND in alcohol Answer :B

Discussion

13.	In context with the transition elements, which of the followingstatements is incorrect ?
Answer» In the highestoxidation states,the transiton metals show basiccharacter and FORM cationic complexes. In the highestoxidation states of the first five transitionelements (Sc to MN), all the 4s and 3d electrons are used forbonding Once the`d^(5)` configuration is exceeded,the tendency to INVOLVE all the 3d electrons in BONDING decrease. In addition to the normal states, the zero oxidation state is also SHOWN by these elementsin complexes. Solution :In the highest oxidation state, transition metals show acidiccharacter and form anionic complexes.

Discussion

14.	In context with the transition element, which of the following statement is incorrect?
Answer» In ADDITION to the normal oxidation states, the zero oxidation state is also shown by these elements in complexes. In the HIGHEST oxidation states, the transition metal show basic character and form cationic complexes. In the highest oxidation states of the first five transition elements (Sc to Mn), all the 4S and 3D electrons are used for bonding. Once the `d^5` configuration is exceeded, the TENDENCY to involve all the 3d electrons in bonding decreases. Answer :B

Discussion

15.	In context with the transition elements, which of the following statements is incorrect ?
Answer» In addition to the normal OXIDATION states, zero oxidation state is also SHOWN by elements in complexes. In the highest oxidation states, transition elements show BASIC character and form cationic complexes In the highest oxidation states of the first fivetransition elements (Sc to Mn). All the 4 s and 3delectrons are used for bonding Once the `d^(5)` CONFIGURATION is exceeded. The tendency to involve all the 3d electrons in bonding decreases. Solution :In the highest oxidation states, the transition METALS cannot form cationic complexes. Also, they show acidic character because in the highest oxidation state. They can only accept the electrons but cannot lose them.

Discussion

16.	Incontext with the industrial preparation of hydrogen from water gas (CO+H_(2))which of the followingis the correctstatement
Answer» co is oxidised to `CO_(2)` with steam in the presence of a FOLLOWEDBY absorpitoin of `CO_(2)` in alkali COand `H_(2)` fractionally separated USING diffeences in their densites CO is removeby absorptioninaqueous`Cu_(2)CI_(2)` SOLUTION `H_(2)` is removed through OCCLUSION with pd Answer :A

Discussion

17.	In context of the lanthanoids, which of the following statement is not correct?
Answer» Availability of 4f electrons RESULTS in the formation of compounds in +4 STATE of all the members of the series There is a gradual DECREASE in the radii of the members with INCREASING atomic number in the series All the members exhibit +3 oxidation state Because of similar properties the separation of lanthanoids is not easy Answer :A

Discussion

18.	IN context of the lanthanoids, which of the following statements is not correct ?
Answer» Because of similar PROPERTIES the seperation of lanthanoids is not easy. Availability of 4f electrons RESULTS in the formation of compounds in +4 state for all the members of the series. There is a gradual DECREASE in the radii of the members with increasing ATOMIC number in the series. All the members exhibit +3 OXIDATION state. Solution :The common oxidation state of lanthanoids is +3.

Discussion

19.	In context of the lanthanoids, which of the following statements about cerium is incorrect?
Answer» There is a gradual decrease in the radii of the members with INCREASING atomic number in the SERIES All the member EXHIBIT +3 oxidation state because of similar properties the separation of lanthanoids is not easy Availability of 4f electrons results in the FORMATION of compounds in +4 state for all the members of the series. Answer :D

Discussion

20.	In context of the lanthanoids , which of the following statement is not correct?
Answer» There is a GRADUAL decrease in the radii of the members with increasing ATOMIC number in the series All the member exhibit `+3` oxidation state Availability of `4f` electrons result in the formation of COMPOUNDS in `+4` state for all member of the series Solution :Availability of `4f` electrons donot RESULTS in the formation of compounds in `+4` state for all the members of the series.

Discussion

21.	In contact process the formation of SO_3 takes place according to the following reaction, 2SO_2+O_2hArr2SO_3,DeltaH=-45.2kcal The formation of SO_3 is fovoured by
Answer» INCREASE of VOLUME Increasing in TEMPERATURE Removal of oxygen Increasing of pressure Answer :D

Discussion

22.	In Contact process impurities of arsenic are removed by:
Answer» `AL(OH)_(3)` `Fe(OH)_(3)` `CR(OH)_(3)` `Fe_(2) O_(3)` ANSWER :B

Discussion

23.	In [Co(NH_3)_4C1_2]C1 the co-ordination number of cobalt is
Answer» 4 6 2 7 Answer :B

Discussion

24.	In compound made up of A and B elements, element B form hcp lattice structure and element A occupy 2/3part of tetrahedral voids, then molecular formula of compound made up of A and B = .........
Answer» `A_3 B_4` `A_4 B_3` `A_2 B_3` `A_3 B_5` ANSWER :B

Discussion

25.	In concentration process of minerals by froth foloatation method , the ore particles float because :
Answer» They are light They are insoluble Their SURFACE is hydrophobic None Answer :C

Discussion

26.	In compound A,1,.0g nitrogen combines with 0.57g oxygen. In compound B,2.0g nitrogen unite with 2.24 g oxygen and in compound Cdd, 3.0g nitrogen combine with 5.11g oxygen. These results obey the law of:
Answer» MULTIPLE PROPORTIONS CONSTANT proportions. reciprocal proportions NONE of these. Answer :A

Discussion

27.	In compound A(C_(30)H_(60)O) following tests are observed negatively. A can be
Answer» an unsaturated ether an epoxide a cyclic ketone a cycloalanol Solution :The compound `C_(30)H_(60)O` has ONE degree of UNSATURATION since it gives negative test with `Br_(2)//H_(2)O,2,4DNP` and `Na` METAL it MUST be an epoxide.

Discussion

28.	In compound A (C_(30)H_(60)O) following tests are observed negatively, A can be
Answer» an UNSATURATED ether an epoxide a CYCLIC ketone a cycloalkanol Solution :N//A

Discussion

29.	In compound A (C_30H_60O)following tests are observed negatively, A can be :
Answer» An unsaturated ether an epoxide A cyclic ketone A cycloalkanol Solution :The compound `C_30H_60O` has ONE degree of UNSATURATION since it gives negative TEST with `Br_2//H_2O, 2,4` DNP and NA metal it must be an epoxide.

Discussion

30.	In complexes off wea field ligands, Delta_(o) lt P (pairing energy), the energy difference between t_(2g) and e_(g) sets is relatively less. Under the unfluence of strong field ligands, Delta_(O) gt p (Pairing energy), the energy difference between t_(2g) and e_(g) sets is relatively high. Q. Select the correct statement regarding [Cr(en)_(2)Cl_(2)]^(+) and [Co(C_(2)O_(4))_(2)(NH_(3))_(2)]^(-) complex ions:
Answer» Both are EQUALLY STABLE complexes Both have equal number of stereoisomers Both are diamagnetic complexes a and C both Answer :B

Discussion

31.	In complexes off wea field ligands, Delta_(o) lt P (pairing energy), the energy difference between t_(2g) and e_(g) sets is relatively less. Under the unfluence of strong field ligands, Delta_(O) gt p (Pairing energy), the energy difference between t_(2g) and e_(g) sets is relatively high. Q. Which of the following is correct statement?
Answer» Complex `[Co(H_(2)O)_(6)]^(2+)` is more STABLE than `[Co(H_(2)O)_(6)]^(3+)` All compounds of `Ni(II)` are bound to be outer-d-orbital complexes Stability constant for `[Ni(en)_(3)]^(2+)` is greater than stability constant for `[Ni(NH_(3))_(6)]^(2+)` `Delta_(OCT)` for `[Cr(H_(2)O)_(6)]^(3+)` is greater than `Delta_(oct)` for `[Cr(NH_(3))_(6)]^(3+)` Answer :C

Discussion

32.	In complexes off wea field ligands, Delta_(o) lt P (pairing energy), the energy difference between t_(2g) and e_(g) sets is relatively less. Under the unfluence of strong field ligands, Delta_(O) gt p (Pairing energy), the energy difference between t_(2g) and e_(g) sets is relatively high. Q. Select the correct increasing order of 10 Dq. value of chromium complexes: (1) [Cr(en)_(3)]^(3+) (2) [Cr(o x)_(3)]^(3-) (3) [CrF_(6)]^(3-) (4) [Cr(H_(2)O)_(6)]^(3+)
Answer» `4 LT 3 lt 1 lt 2` `3 lt 4 lt 2 lt 1` `4 lt 3 lt 2 lt 1` `3 lt 4 lt 1 lt 2` Answer :B

Discussion

33.	In complexes of gold, the coordination number of gold may be
Answer» 6 4 5 2 Solution :CN of AG and AU MAY be 2 or 4

Discussion

34.	In complexes more stability is shown by:-
Answer» `[Fe(H_(2)O)_(6)]^(3+)` `[Fe(CN)_(6)]^(3-)` `[Fe(C_(2)O_(4))_(3)]^(3-)` `[FeCl_(6)]^(3-)` ANSWER :B

Discussion

35.	In complexes more stability is shown by :
Answer» `[FE(H_(2)O)_(6)]^(3+)` `[Fe(CN)_(6)]^(3-)` `[Fe(C_(2)O_(4))_(3)]^(3-)` `[Fe(CL)_(6)]^(3-)` Solution :`[Fe(C_(2)O_(4))_(3)]^(3-)` is more stable due to chelation.

Discussion

36.	In complete combustion of petrol or diesel oil in automobile engines from can be best detected by testing the fuel gas for the presence of :
Answer» `CO +H_2O` `CO` `NO_2` `SO_2` ANSWER :B

Discussion

37.	In complexes, metal atom acts as:
Answer» ANSWER :D

Discussion

38.	In complex compounds the metal atom or ion acts as a
Answer» LEWIS ACID Lewis BASE BRONSTED acid Bronsted base Answer :A

Discussion

39.	In comparison to the zeolite process for the removal of permanent hardness, the synthetic resins method is
Answer» more EFFICIENT as it can EXCHANGE only CATIONS less efficient as it can exchange only anions less efficient as it can exchange only cations more efficient as it can exchange both cations as WELL as anions Answer :C

Discussion

40.	In comparison to ferrous salts , ferric salts are :
Answer» More STABLE Less stable Equally stable NONE of the above Answer :A

Discussion

41.	In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl_(2) solution is …….
Answer» the same about twice about three TIMES about six times SOLUTION :Explanation : Depression in freezing point is a colligative property. In case of `MgCl_(2)` value of van.t. HOFF factor will be more. No. of ions yielded when a molecule of `MgCl_(2)` gets DISSOCIATED in its aqueous solution is = 3. THUS one molecule of 0.01 M `MgCl_(2)` given out three particles / ions in solution, thereby increasing the number of particles present in its solution to three times. It is because of this that depression in freezing point of 0.01 M `MgCl_(2)` will be three times as compared to that of 0.01 M - glucose solution, where no dissociation of the molecule takes place.

Discussion

42.	In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl_(2) solution is ………….. .
Answer» the same about twice about three times about SIX times Solution :`"0.01 M MgCl"_(2)=0.03 M` PARTICLE concentration which is three times in comparison to 0.01 M GLUCOSE. HENCE, depression will be about three times.

Discussion

43.	In comparison of ferrous salts, ferric salts are:
Answer» more stable less stable equally stable None of these Answer :A

Discussion

44.	In coparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl_(2) solution is……
Answer» the same about twice about three times about SIX times Solution :is the correct answer. Glucose is a molecular solid while `MgCI_(2)` being lonic, provides (0.03 M) MOLES of inos per LITRE. It is thrice the number os inos procided by glucose (0.01 M).

Discussion

45.	In coming years, skin related disorders will be more common due to
Answer» Pollutants in air Use of detergents Water pollution Depletion of ozone layer Solution :In coming years, when the ozone layer BECOMES THINNER or has HOLE, ultraviolet radiations come directly that causes CANCER especially related to SKIN like melanoma

Discussion

46.	In the coming years, skin related disorders will be more common due to :
Answer» pollutants in AIR use of detergents water pollution depletion of ozone LAYER Solution :In coming years, when the ozone layer will become thinner or has hole, ultraviolet radiations will come directly to the earth that will cause cancer ESPECIALLY related to SKIN like melanoma.

Discussion

47.	In column chromatography , the mixture whose different components are to be seperated is dissolved in __________.
Answer» STATIONARY phase mobile phase eluents alumina Answer :B

Discussion

48.	In colloidal state, particle size ranges from :
Answer» 1 to `10A^@` 20 to `50A^@` 10 to `1000A^@` 1 to `280A^@` ANSWER :C

Discussion

49.	In colour discharge tubes, which is used:
Answer» Ne Argon Kr He Answer :B

Discussion

50.	In colloidal state particle size ranges from
Answer» `1 - 10 Å` `20 - 50 Å` `10 - 1000 Å` `1 – 280 Å` ANSWER :C

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

In conversion of 2-butanone to propanoic acid which reagent is used

In countries nearer to polar region, the roads are sprinkled with CaCl_(2). This is

In conversion of 2-butanone to propanoic acid when reagent is used.

In contextof the lanthanoids , which of the followingstatements is not correct ?

In continuous etherification process 1^(st)step is

In context with the transition elements, which of the followingstatements is incorrect ?

In context with the transition element, which of the following statement is incorrect?

In context with the transition elements, which of the following statements is incorrect ?

Incontext with the industrial preparation of hydrogen from water gas (CO+H_(2))which of the followingis the correctstatement

In context of the lanthanoids, which of the following statement is not correct?

IN context of the lanthanoids, which of the following statements is not correct ?

In context of the lanthanoids, which of the following statements about cerium is incorrect?

In context of the lanthanoids , which of the following statement is not correct?

In contact process the formation of SO_3 takes place according to the following reaction, 2SO_2+O_2hArr2SO_3,DeltaH=-45.2kcal The formation of SO_3 is fovoured by

In Contact process impurities of arsenic are removed by:

In [Co(NH_3)_4C1_2]C1 the co-ordination number of cobalt is

In compound made up of A and B elements, element B form hcp lattice structure and element A occupy 2/3part of tetrahedral voids, then molecular formula of compound made up of A and B = .........

In concentration process of minerals by froth foloatation method , the ore particles float because :

In compound A,1,.0g nitrogen combines with 0.57g oxygen. In compound B,2.0g nitrogen unite with 2.24 g oxygen and in compound Cdd, 3.0g nitrogen combine with 5.11g oxygen. These results obey the law of:

In compound A(C_(30)H_(60)O) following tests are observed negatively. A can be

In compound A (C_(30)H_(60)O) following tests are observed negatively, A can be

In compound A (C_30H_60O)following tests are observed negatively, A can be :

In complexes of gold, the coordination number of gold may be

In complexes more stability is shown by:-

In complexes more stability is shown by :

In complete combustion of petrol or diesel oil in automobile engines from can be best detected by testing the fuel gas for the presence of :

In complexes, metal atom acts as:

In complex compounds the metal atom or ion acts as a

In comparison to the zeolite process for the removal of permanent hardness, the synthetic resins method is

In comparison to ferrous salts , ferric salts are :

In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl_(2) solution is …….

In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl_(2) solution is ………….. .

In comparison of ferrous salts, ferric salts are:

In coparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl_(2) solution is……

In coming years, skin related disorders will be more common due to

In the coming years, skin related disorders will be more common due to :

In column chromatography , the mixture whose different components are to be seperated is dissolved in __________.

In colloidal state, particle size ranges from :

In colour discharge tubes, which is used:

In colloidal state particle size ranges from