94420 + Interview Questions in Chemistry in Class 12

1.	Below point 'A' FeO can
Answer» be REDUCED by CARBON MONOXIDE only. be reduced by both carbon monoxide and carbon. be reduced by carbon only. not be reduced by both carbon and carbon monoxide. Solution :It is the CORRECT ANSWER.

Discussion

2.	Bell metal is an alloy of ____ and _____ .
Answer» SOLUTION :`80%` of CU, `20%` of SN

Discussion

3.	Bell metal is an alloy of :
Answer» `SN +PB ` `Cu + Sn` `Sn +Sb` None Answer :B

Discussion

4.	Belstein's test is used for the detection of :
Answer» NITROGEN Sulphur Halogens Phosphorus. Answer :C

Discussion

5.	Beilstein test cannot be considered as a confirmatory test for thepresence of halogen in a compound - why?
Answer» Solution :Manyhalogen - free compounds e.g., certain DERIVATIVES of pyridine and quionline, purines, acid amides, urea, thiourea, cyano compounds etc. give this TEST presumably owing to theformation of VOLATILE copper cyanides.

Discussion

6.	An aqueous solution is heated until it begins to boil. The atmospheric pressure is 760 mm of Hg. The boiling temperature will be:
Answer» `100^@C` `gt100^@C` `lt100^@C` None Answer :B

Discussion

7.	Before reduction, the ore is first converted into the oxide of metal of interest. Give reason.
Answer» SOLUTION :(i) In the concentrated ORE, the metal exists in positive oxidation STATE and hence it is to be reduced to its elemental state. (ii) From the principles of thermodynamics, that the reduction of oxide is easier when COMPARED to reduction of other compounds of metal and hence, before reduction the ore is first converted into the oxide of metal of INTEREST.

Discussion

8.	Before reacting aniline with HNO_3 for nitration, it is converted to acetanilide. Why is this done and how is nitroaniline obtained subsequently ?
Answer» Solution :`-NH_2` GROUP is a very STRONG ACTIVATING group. In order to get the monosubstituted product, the activating effect of the `NH_2` group has to be reduced. This is achieved by acetylating the aromatic amine. After nitration, acetyl group is then removed by the hydrolysis to get BACK the amine.

Discussion

9.	Before reacting aniline with HNO_(3) for nitration, it is converted to acetanilide. Why is this done and how is nitroaniline obtained subsequently ?
Answer» <P> Solution :It is because aniline gets oxidised and protonated and GIVES 47% m-nitroaniline on direct NITRATION. THEREFORE, it is converted into acetanilide and then nitrated. ANILIDE group activates the ring at o- and p- positions. We get o- and p- nitroacetanilide which on hydrolysis gives o- and p- nitroaniline.

Discussion

10.	Before introducing FeO in blast fumace, it is converted to Fe_(2)O_(3) by roasting so that
Answer» it may not REMOVED as slag with silica it may not evaporate in the fumace presence of it may INCREASE the m pt. of charge None of these Solution :FeO is CAPABLE forming slag with `SiO_(2)` `SiO_(2)+FeO to FeSiO_(3)`

Discussion

11.	RCOR is not converted to RCH_2R by:
Answer» It MAY not be REMOVED as SLAG with silica It may not evaporate in the furnace Presence of it may increase the m.pt. of CHARGE NONE of the above Answer :A

Discussion

12.	Before introducing FeO in blast furnace, it is converted to Fe_2O_3 by roasting so that:
Answer» It MAY not be removed as SLAG with silica It may not evaporate in the furnace Presence of it may increase the m.pt. of CHARGE none of the above Answer :A

Discussion

13.	Before adding the reagents of group III, the solution is heated with some concentrated HNO_(3) in order to
Answer» OXIDISE `Fe^(2+)` to `Fe^(3+)` oxidise `Cr^(3+)` to `Cr_(2)O_(7)^(2-)` LOWER the pH increase the `[NO_(2)]` Answer :A

Discussion

14.	Bee.s wax is :
Answer» Tripalmitin Acetyl PALMITATE Myricyl palmitate Myricyl ceorate Answer :C

Discussion

15.	Bee's wax is :
Answer» Tripalmitin Acetyl PALMITATE Myricyl palmitate Myricyl ceorate Answer :C

Discussion

16.	BeCl_(2) is not isostructural with
Answer» `IC l_(2)^(-)` `C_(2)H_(2)` `XeF_(2)` `GeCl_(2)` Solution :

Discussion

17.	BeCl_2 + LiAIH_4to X+ LiCI + AICI_3
Answer» X is LiH X is `BeH_2` X is `BeCI_2. 2H_2 O` NONE ANSWER :B

Discussion

18.	Beckmann's thermometer are used to measures:
Answer» BOILING POINT of the solution FREEZING point of the solution Any temperature Elevation in boiling point or DEPRESSION in freezing point Answer :D

Discussion

19.	Because of the compact nature of oxygen atom, it has __________ electron gain enthalpy than sulphur.
Answer» SOLUTION :LESS NEGATIVE

Discussion

20.	Because of resonance the oxygen atom of -OH group of phenol
Answer» ACQUIRES POSITIVE charge Acquires NEGATIVE charge Remains uneffected Liberates Solution :

Discussion

21.	Because of lanthanoide contraction, which of the following pairs of elements have nearly same atomic radii ? (Numbers in the parenthesis are atomic numbers )
Answer» Ti (22) and Zr (40) Zr (40) and Nb (41) Zr (40) and HF (72) Zr (40) and Ta (73) ANSWER :C

Discussion

22.	Because of lanthanoidcontraction, which of the following pairs of elements have nearly same atomic radii ? ( Numbers in parenthesis are atomic numbers )
Answer» Zr(40) and Hf (72) Zr(40) and Ta ( 73) Ti(22 ) and Zr (40) Zr(40)and Nb(41) Solution :Zr( 40) andHf ( 72) LIE in the same group and Hf comes after La. Hence, Zr and Hf have NEARLY same SIZE due to lanthanoidcontraction.

Discussion

23.	Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic radii? (Number in the parenthesis are atomic numbers)
Answer» Ti(22) and Zr(40) Zr (40) and Nb(41) Zr (40) and Hf (72) Zr (40) and Ta (73) Solution :Due to lanthanoid contraction ATOMIC RADII of Zr and Hf is almost similar

Discussion

24.	Because of lanthanoid contraction, which of the folliwng pairs of elements have nearly same atomic radii ? (Numbers in the paren thesis are atomic numbers)
Answer» Zr(40) and Hf(72) Zr(40) and Ta(73) TI(22) and Zr(40) Zr(40) and NB(41) Answer :A

Discussion

25.	Because of lanthanoid contraction, which of the following pair sof elements have nearly same atomic raddi ? (Numbers in the parenthesis are atomic numbers)
Answer» Zr(40) and Nb(41) Zr (40) and Hf(72) Zr(40) and Ta (73) Ti (22) and Zr (40) Solution :DUE to lanthanoid conatraction atomic RADII of Zr and Hf is ALMOST similar.

Discussion

26.	Because of lanthanoid contraction :
Answer» separation of the elements is possible there is a very SMALL DIFFERENCE in the atomic size of thetransition metals of 5th and 6th PERIOD and PRESENT in the same group. there is a gradual decrease in the basic strengths of the hydroxides of lanthanoids All are correct. SOLUTION :all thestatements are correct.

Discussion

27.	Because of its anti blood clotting action, aspirin finds use in prevention of ________________.
Answer» SOLUTION :HEART ATTACKS

Discussion

28.	BDC + Cu_(2)Cl_(2)+HCl to Chlorobenzene. This reaction is also called
Answer» Chlorination SANDMEYER's REACTION Perkin reaction SUBSTITUTION reaction Answer :2

Discussion

29.	Beach sand mineral, monazite, is a rich source of thorium, available in large quantities in the state of Kerala in india. A typical monazite sample contains about 9% ThO_(2) and 0.35% U_(3)O_(8).^(208)Pb and ^(206)Pb are the stable end-products in the redioactive decay series of ^(232)Th and .^(238)U, respectively. All the lead (Pb) found in monazite is of radiogenic origin. The isotopic atom ratio ^(208)Pb//^(232)Th and .^(238)U are 1.41xx10^(10) years and 4.47xx10^(9) years, respectively. Assume that ^(208)Pb, ^(232)Th and .^(238)U remained entirely in the monazite sample since the formation of monazite mineral. Thorium- 232 is a fertile material for nuclear energy. In thermal neutron irradiation, it absorbs a neutron and the resulting isotope forms ^(233)U by successive beta-decays. Write the nuclear reactions for the formation of ^(233)U from ^(232)Th. In nuclear fission of ^(233)U a complex mixture of radioactive decay as shown below: _(42)^(101)Mo underset(t_(1//2)=14.6 min)(rarr)_(43)^(101)Tc underset(t_(1//2)=14.3 min)(rarr)_(44)^(101)Ru
Answer» Answer :`^(232)Th overset(((N, GAMMA)))(RARR)`^(233)Th overset(BETA-)(rarr) `^(233)Pa overset(beta-)(rarr) `^(233)U````

Discussion

30.	Be resembles very much in its properties with:
Answer» Zn Ra Al Hg Answer :C

Discussion

31.	Be and Al have following resemblance due to diagonal relationship
Answer» have nearly equal electronegativity form amphoteric oxides have same charge/radius ratio both form DIMERIC hlides SOLUTION :(A, B, C, D)

Discussion

32.	Be and Al exhibit diagonal relationship. Which of the following statements about them is/are not true I. Both react with HCl to liberate H_2 II. They are made passive by HNO_3 III. Their carbides give acetylene on treatment with water IV. Their oxides are amphoteric
Answer» (III) and (IV) (I) and (III) (I) only (III) only Solution :The CARBIDES of both Be and AL liberate methane with water. `Be_(2)C+ 2H_(2)O to 2BeO +CH_(4)` `Al_(4)C_(3) +6H_(2)O to 2Al_(2) O_(3) +3 CH_(4)`

Discussion

33.	BCl_3 is a__________ Lewis acid than BF_3.
Answer» SOLUTION :STRONGER

Discussion

34.	BCl_(3) does not exist as dimer but BH_(3) exist as dimer (B_(2)H_(6 )) because :-
Answer» <P>Chlorine is more electronegative than hydrogen There is `p PI-p pi` back bonding in `BCl_(3)`but `BH_(3)` does not contain such bonding Large sized chlorine atoms do not fit between the small boron atoms WHEREAS small sized hydrogen atoms get FITTED between boron atoms. None of these Answer :C

Discussion

35.	Bauxite, the ore of aluminium, is purifid by which process?
Answer» Hoope's process HALL's process Mond's process LIQUATION process SOLUTION :Hall's process. It is fact.

Discussion

36.	Bauxite ore is made up of Al_(2)O_(3) + SiO_(2) + TiO_(2) + Fe_(2)O_(3). This ore is treated with conc. NaOH solution at 500 K and 35 bar pressure for few hours and filltered hot. In the filtrate the species present are :
Answer» `NAAL(OH)_(4)` only `Na_(2)TI(OH)_(6)` only `NaAl(OH)_(4) and Na_(2)SiO_(3)` both `Na_(2)SiO_(3)` only Answer :C

Discussion

37.	Bauxite ore is made up ofAl_2O_3 + SiO_2 + TiO_2 + Fe_2O_3. This ore is treated with conc. NaOH solution at 500 K and 35 bar pressure for few hours and filtered. The species present in it are...
Answer» `NAAL(OH)`4 only `NA Ti(OH)_6` only `NaAl(OH)_4` and `Na_2SiO_3` both `Na_2SiO_3` only Answer :C

Discussion

38.	Bauxite No underset(N_2)overset(+C)(rarr)underset(CO)(AIN)overset(H_2O)(rarr)Al(OH)_(3) overset(Delta)(rarr)Al_2O_3 + NH_3 The flow sheet is for ........
Answer» BAYER's PROCESS Serpeck's process Hall-Heroult process KROLL's process ANSWER :B

Discussion

39.	Bauxite isthe principleore ofaluminium. Itcannot be reducedwith carbon to give thecorrespondingmetalbut whenheatedat2273K, it gives compound (X) which upontreatment withwatergives a gas (Y) which isthe majorconstituent of natural gas.Identify(X) and (Y) andexplainthe reactionsinvolvedtherein.
Answer» Solution :Bauxineishydratedalumina` (A_ 2 l _ 2O_ 3.2 H_2 O )`. Onheating strongly with carbon,it gives alumininum carbide(X). ` "" underset("Bauxite")(Al_2O_3.2H_2O)overset(1473K)to underset("ALUMINA")(Al_2O_3) +2 H_2O ` ` 2 Al_2O_3+ C overset (2273K) tounderset("Aluminium carbide (X)") (Al_4 C_3) +6CO` `underset("Aluminium carbide (X)")(Al_4C_3 ) +12 H_2 Oto4Al (OH)_ 3+underset(" (CONSTITUENT ofnaturalgas )")underset ("METHANE (Y)") (3CH_ 4)`

Discussion

40.	Bauxite is purifiedby…….
Answer» CYANIDE leaching Alkali leaching Acid leaching Hand picking Answer :A

Discussion

41.	Bauxite is an ore of aluminium while china is not .Why?
Answer» Solution :Bauxite and CHINA CLAY ,BOTHARE minerals of ALUMINIUM.However ,aluminium can be commercially EXTRACTED from bauxite while extraction from china clay is not a profitable one.Hence the mineral,bauxite is an ore of aluminium while china clay is not.

Discussion

42.	Bauxite is an ore of :
Answer» Aluminium Calcium COPPER Zinc Answer :A

Discussion

43.	Bauxite is a mineral used for the extraction of
Answer» Ca Cu Al Fe Answer :C

Discussion

44.	Bauxite has the composition
Answer» `Al_2O_3` `Al_2O_3 CDOT 2H_2O` `Al_2O_3 cdot 2H_2O` NONE of these ANSWER :B

Discussion

45.	Bauxite containing impurities of iron oxide is purified by
Answer» HOOP's PROCESS Serpeck's process Baeyer's process Electrolytic process Solution :For the PURIFICATION of red bauxite which contains iron oxide as impurity `to` Bayer's process. For the purification of white bauxite which contain SILICA as the main impurity serpeck's process.

Discussion

46.	Bauxite, an ore of aluminium is purified by
Answer» Halls' process Serpek's process Bayer's process All of these SOLUTION :Hall.s and Bayer.s processes are used if ALUMINIUM ore contains iron OXIDE as IMPURITY, while Serpek.s process is used when `SiO_2` is present as an impurity.

Discussion

47.	Bauxite, Al_2O_3.xH_2O is an important ore of aluminium. It is concentrated by leaching. Explain the method.
Answer» ANSWER :REFER to THEORY SECTION 6.2.4

Discussion

48.	Bauxineore ismade up ofAl_2 O_ 3 + SiO_2 + TiO_2 + Fe_2O_3.This ore istreatedwith conc.NaOHsolutionat500 K and35 bar pressureforfew hours andfiteredhot.Inthefiltrate,the speciespresentare :
Answer» ` NAAL(OH) _4` only `Na_2 Ti(OH)_6`only ` NaAl(OH)_4 `and` Na_2SiO_3 `both ` Na_2 SiO_3 ` only SOLUTION :Both` Al_2O_ 3and SiO_ 2 `dissolvein NaOHas NaAl ` (OH)_4 and Na_ 2 SiO_ 3`respectively.

Discussion

49.	Battery acid (H_(2)SO_(4)) has density 1.285 g cm^(-3) , 10.0 cm^(3) of this acid is diluted to 1L . 25.0 cm^(3) of this diluted solution requires 25.0 cm^(3) of 0.1 N sodium hydroxide solution for neutralization. The percentage of sulphuric acid by massin the battery acid is :
Answer» 98 38 19 49 Answer :B

Discussion

50.	BaTiO3 crystallizes in the prevoskite structure. This structure may be described as a cubic lattice with barium ions occupying the corner of the unit cell, oxide ions occupying the face-centers and titanium ion occupying the center of the unit cell. (a) If titanium is described as occupying holes in BaO lattice, what type of holes does it occupy? (b) What fraction of this type hole does it occupy ?
Answer» ANSWER :OCTAHEDRAL,B 1/4

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Below point 'A' FeO can

Bell metal is an alloy of ____ and _____ .

Bell metal is an alloy of :

Belstein's test is used for the detection of :

Beilstein test cannot be considered as a confirmatory test for thepresence of halogen in a compound - why?

An aqueous solution is heated until it begins to boil. The atmospheric pressure is 760 mm of Hg. The boiling temperature will be:

Before reduction, the ore is first converted into the oxide of metal of interest. Give reason.

Before reacting aniline with HNO_3 for nitration, it is converted to acetanilide. Why is this done and how is nitroaniline obtained subsequently ?

Before reacting aniline with HNO_(3) for nitration, it is converted to acetanilide. Why is this done and how is nitroaniline obtained subsequently ?

Before introducing FeO in blast fumace, it is converted to Fe_(2)O_(3) by roasting so that

RCOR is not converted to RCH_2R by:

Before introducing FeO in blast furnace, it is converted to Fe_2O_3 by roasting so that:

Before adding the reagents of group III, the solution is heated with some concentrated HNO_(3) in order to

Bee.s wax is :

Bee's wax is :

BeCl_(2) is not isostructural with

BeCl_2 + LiAIH_4to X+ LiCI + AICI_3

Beckmann's thermometer are used to measures:

Because of the compact nature of oxygen atom, it has __________ electron gain enthalpy than sulphur.

Because of resonance the oxygen atom of -OH group of phenol

Because of lanthanoide contraction, which of the following pairs of elements have nearly same atomic radii ? (Numbers in the parenthesis are atomic numbers )

Because of lanthanoidcontraction, which of the following pairs of elements have nearly same atomic radii ? ( Numbers in parenthesis are atomic numbers )

Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic radii? (Number in the parenthesis are atomic numbers)

Because of lanthanoid contraction, which of the folliwng pairs of elements have nearly same atomic radii ? (Numbers in the paren thesis are atomic numbers)

Because of lanthanoid contraction, which of the following pair sof elements have nearly same atomic raddi ? (Numbers in the parenthesis are atomic numbers)

Because of lanthanoid contraction :

Because of its anti blood clotting action, aspirin finds use in prevention of ________________.

BDC + Cu_(2)Cl_(2)+HCl to Chlorobenzene. This reaction is also called

Be resembles very much in its properties with:

Be and Al have following resemblance due to diagonal relationship

Be and Al exhibit diagonal relationship. Which of the following statements about them is/are not true I. Both react with HCl to liberate H_2 II. They are made passive by HNO_3 III. Their carbides give acetylene on treatment with water IV. Their oxides are amphoteric

BCl_3 is a__________ Lewis acid than BF_3.

BCl_(3) does not exist as dimer but BH_(3) exist as dimer (B_(2)H_(6 )) because :-

Bauxite, the ore of aluminium, is purifid by which process?

Bauxite ore is made up of Al_(2)O_(3) + SiO_(2) + TiO_(2) + Fe_(2)O_(3). This ore is treated with conc. NaOH solution at 500 K and 35 bar pressure for few hours and filltered hot. In the filtrate the species present are :

Bauxite ore is made up ofAl_2O_3 + SiO_2 + TiO_2 + Fe_2O_3. This ore is treated with conc. NaOH solution at 500 K and 35 bar pressure for few hours and filtered. The species present in it are...

Bauxite No underset(N_2)overset(+C)(rarr)underset(CO)(AIN)overset(H_2O)(rarr)Al(OH)_(3) overset(Delta)(rarr)Al_2O_3 + NH_3 The flow sheet is for ........

Bauxite isthe principleore ofaluminium. Itcannot be reducedwith carbon to give thecorrespondingmetalbut whenheatedat2273K, it gives compound (X) which upontreatment withwatergives a gas (Y) which isthe majorconstituent of natural gas.Identify(X) and (Y) andexplainthe reactionsinvolvedtherein.

Bauxite is purifiedby…….

Bauxite is an ore of aluminium while china is not .Why?

Bauxite is an ore of :

Bauxite is a mineral used for the extraction of

Bauxite has the composition

Bauxite containing impurities of iron oxide is purified by

Bauxite, an ore of aluminium is purified by

Bauxite, Al_2O_3.xH_2O is an important ore of aluminium. It is concentrated by leaching. Explain the method.

Bauxineore ismade up ofAl_2 O_ 3 + SiO_2 + TiO_2 + Fe_2O_3.This ore istreatedwith conc.NaOHsolutionat500 K and35 bar pressureforfew hours andfiteredhot.Inthefiltrate,the speciespresentare :

Battery acid (H_(2)SO_(4)) has density 1.285 g cm^(-3) , 10.0 cm^(3) of this acid is diluted to 1L . 25.0 cm^(3) of this diluted solution requires 25.0 cm^(3) of 0.1 N sodium hydroxide solution for neutralization. The percentage of sulphuric acid by massin the battery acid is :

Bell metal is an alloy of and _ .