94420 + Interview Questions in Chemistry in Class 12

1.	Specify the oxidation numbers of the metals in the following coordination entities : [Cr(NH_(3))_(3)Cl_(3)]
Answer» Solution :OXIDATION NUMBERS can be obtained by adding the oxidation numbers of constituents and equating them with the overall charge on the ion, or ZERO, if it is a molecular complex. Assuming x as the oxidation NUMBER of the METAL, we have `x + 0 + 3(-1) = 0` or `x = +3`

Discussion

2.	Specify the coordination of geometry and hybrization of N and B atoms in 1: 1 comples of BF_(3) and NH_(3)
Answer» N:tetrahedral, `sp^(3)`, B:tetrahedral, `sp^(3)`. N:pyramidal, `sp^(3)`, B:tetrahedral, `sp^(3)`. N:pyramidal, `sp^(3)`, B:Planar, `sp^(3)`. N:pyramidal, `sp^(3),`B:tetrahedral, `sp^(3)`. ANSWER :A

Discussion

3.	Specify the oxidation numbers of the metals in the following coordination entities : [CoBr_(2)(en)_(2)]^(+)
Answer» SOLUTION :Oxidation NUMBERS can be obtained by ADDING the oxidation numbers of constituents and equating them with the overall charge on the ion, or zero, if it is a molecular complex. Assuming x as the oxidation NUMBER of the metal, we have `x + 2(-1) + 0 = +1` or `x = +3`

Discussion

4.	Specify the coordination geometry around and hybridisation of N and B atoms in a 1 : 1 complex of BF_(3) and NH_(3)
Answer» N : tetrahedral, `sp^(3)` , B : tetrahedral, `sp^(3)` N : pyramidal, `sp^(3)` , B : pyramidal, `sp^(3)` N : pyramidal, `sp^(3)` , B : PLANAR, `sp^(2)` N : pyramidal, `sp^(3)` , B : tetrahedral, `sp^(3)` Solution :In the 1 : 1 complex, `H_(3)N rarr BF_(3)`, both N and B have `sp^(3)` hybridisation and tetrahedral geometry.

Discussion

5.	Specify the coordination geometry and hybridisation around N and B atoms in a 1:1 complex of BF_(3) and NH_(3)
Answer» N: TETRAHEDRAL, `sp^(3): B:` tetrahedral , `sp^(3)` N:PYRAMIDAL,`SP_(3)^(3-)`, B: Pyramidal, `sp^(3)` N: pyramidal, `sp^(3)`, B: PLANAR, `sp^(2)` N: pyramidal, `sp^(3)`, B: tetrahedral, `sp^(3)` ANSWER :A

Discussion

6.	Specificity of enzyme is due to
Answer» the SEQUENCE of amino acids SECONDARY STRUCTURE TERTIARY structure all of the above Solution :all of the above

Discussion

7.	Specify the coordination geometry around and the hybridisation of N and B atoms in 1 : 1 complex of BF_(3) and NH_(3).
Answer» N : tetrahedral, `sp^(3),B:` tetrahedral, `sp^(3)` N : PYRAMIDAL, `sp^(3),B:` tetrahedral, `sp^(3)` N : pyramidal, `sp^(3),B:` planar, `sp^(2)` N : pyramidal, `sp^(3)`, B : pyramidal, `sp^(3)` ANSWER :A

Discussion

8.	Specific impluse of a rocket and the critical temperature of the fuel reacted in the motor of the rocket has the relationship
Answer» `I_(s) prop sqrt((1//T_(c)))` `I_(s) prop 1//T_(c)` `I_(s) prop sqrt((T_(c)))` `I_(s) prop T_(c)` SOLUTION :The energy of propellant is measurement in terms of a specific impulse INSIDE the motor of the ROCKET. It depend upon the flame temperature and average molecular mass of the gaseous products coming OT of the rocket nozzle. The specific impulse is given by the following relationship with the average molecular mass M and the flame temperature T, `I_(s) = sqrt(T_(c)//M)`.

Discussion

9.	Specific reagent for decarboxylation is:
Answer» `CaCO_3` CaO+NaOH NaOH `CaCI_2` ANSWER :D

Discussion

10.	Specific heat of aluminium is 0.214 cal/g^(@)C. Heat required to raise the temperature of 40.0 g of Al from 20^(@) to 30^(@)C is
Answer» 85.6 cal 3.2 cal 171.2 cal 342.4 cal Answer :A

Discussion

11.	Specific conductivity of N/35 KCl at 298 K is 0.002768 ohm^(-1) cm^(-1) and it has resistance of 520 ohm. A N/25 solution of a salt kept in the same cell was found to have a resistance of 300 ohm at 298 K. Calculate equivalent conductance of the solution.
Answer» SOLUTION :Cell constant = `kappa xx R` `= 0.002768 xx 520 = 1.43936 CM^(-1)` specific conductivity for salt solution , `kappa ` = Cell constant `xx` conductance `= 1.43936 xx (1)/(300)` `= 0.00478 ohm^(-1) cm^(-1)` `LAMBDA = (0.00478 xx 1000)/(1//25)` `= 119.5S cm^(2) "EQUIV"^(-1)`

Discussion

12.	Specific gravity of sulphuric acid in lead accumulator is
Answer» 1 1.5 1.28 1.17 Solution :DESCRIPTION of LEAD ACCUMULATOR.

Discussion

13.	Specific gravity of slag is :
Answer» ALWAYS HIGHER than molten METAL Always higher than molten metal Always LESS than molten metal Same as that of molten metal Answer :B

Discussion

14.	Specific conductivity of 0.5 mol/dm^(3)" "AgNO_(3) solution at 298 K temperature is 5.76xx10^(-3)" S "cm^(-1), then molar conductivity is. . .
Answer» `0.086` `28.8` `2.88` `11.52` SOLUTION :`lamda_(m)=(1000xxK)/(M)` `=(5.76xx10^(-3))/(0.5)=11.52" S "CM^(2)`/mol

Discussion

15.	Specific conductivity of a solution
Answer» INCREASES with dilution decreases with dilution remains UNCHANGED with dilution depends on MASS of electrolyte ANSWER :B

Discussion

16.	Specific conductivity of 0.1 M NaCl aqueous solution is 1.06xx10^(-2)ohm^(-1)cm^(-1), then what is its molar conductivity in ohm^(-1)cm^(2)mol^(-1) ?
Answer» `1.06xx10^(2)` `1.06xx10^(3)` `1.06xx10^(4)` 53 Solution :`Lamda_(m)=(Kxx1000)/(M)=(1.06xx10xx^(-2)xx1000)/(0.1)` `=1.06xx10^(2)ohm^(-1)cm^(2)mol^(-1)`.

Discussion

17.	Specific conductance of pure water at 25^(@)C is 0.58 xx 10^(-7) "mho cm"^(-1). Calculate ionic product of water (K_(w)) if ionic conductances of H^(+) and OH^(+) ions at infinite dilution are 350 and 198 mho cm^(2) respectively at 25^(@)C.
Answer» SOLUTION :`1 XX 10^(-14) ("mole/litre")^(2)`

Discussion

18.	Specific conductance of saturated solution of AgBr is 8.486xx10^(-7)ohm^(-1)cm^(-1) at 25^(@). Specific conductance of pure water at 25^(@)C is 0.75xx10^(-6)ohm^(-1)cm^(-1)." "._m^(^^oo)for KBr, AgNO_3 and KNO_3 are 137.4,133,131 (S cm^2 mol^(-1)) respectively. Calculate the solubility of AgBr in gm/litre
Answer» ANSWER :A::C::D

Discussion

19.	Specific conductance of "1 M KNO"_(3) solution is observed to be 5.55 xx 10^(-3)" mho.cm"^(-1). What is the equivalent conductance of KNO_(3) when one litre of the solution is used ?
Answer» SOLUTION :`"5.55 mho.cm"^(2)."GM. EQUIV"^(-1)`

Discussion

20.	Specific conductance of 0.1 M sodium chloride solution is 1.06xx10^(-2)ohm^(-1)cm^(-1).Its molar conductance in ohm^(-1)cm^(2)mol^(-1) is
Answer» `1.06xx10^(2)` `1.06xx19^(3)` `1.06xx10^(4)` 53 Answer :A

Discussion

21.	Specific conductance of 0.1 M Nitric acid is 6.3 xx 10^(-2) "ohm"^(-1) cm^(-1) "mol"^(-1) The molar conductance of the solution is
Answer» `630" OHM"^(-1) CM^(2) " mol"^(-1)` `315 ohm^(-1) cm^(2) " mol"^(-1)` `100 ohm^(-1) cm^(2) "mol"^(-1)` `6300 ohm^(-1) cm^(2) "mol"^(-1)` ANSWER :A

Discussion

22.	Specific conductance =molar conductance xx cell constant. Is it true or false?
Answer» SOLUTION :OBSERVED CONDUCTANCE

Discussion

23.	Specific conductance for strong electrolyte on dilution ________
Answer» SOLUTION :DECREASES RAPIDLY.

Discussion

24.	Specific conductance=________x cell constant.
Answer» SOLUTION :OBSERVED CONDUCTANCE

Discussion

25.	Specific conductivity of a 0.12 normal solution of an electrolyte is 0.023 ohm^(-1)cm^(-1). Determine its equivalent conductivity.
Answer» Solution :`wedge_(eq)=kappaxx(1000)/("Normality")=0.024Omega^(-1)cm^(-1)xx(1000CM^(3)L^(-1))/(0.12g" "eqL^(-1))=200OMEGA^(-1)cm^(2)eq^(-1)`.

Discussion

26.	How does specific conductance vary with dilution?
Answer» SOLUTION :DECREASES RAPIDLY.

Discussion

27.	Species present in acidic aq. solution are :
Answer» `H_(3)O^(+)` `H_(5)O_(2)^(+)` `H_(7)O_(3)^(+)` All SOLUTION :`H_(2) O +H^(+) to H_(3)O^(+) OVERSET(H_(2)O)to H_(5)O_(2)^(+) overset(H_(2)O)to H_(7)O_(3)^(+)`

Discussion

28.	Species which are isoelectronic with OF_(2) is/are
Answer» `CLO^(-)` CLF `NH_(2)CL` `ClO_(2)` Solution :`ClO^(-)` (17 + 8 + 1 = 26), ClF (17 + 9 = 26) and `NH_(2)Cl` (7 + 2 + 17 = 26) all the THREE are isoelectronic. Only `ClO_(2)` (17 + 2 `xx` 8 = 33) is not isoelectronic.

Discussion

29.	Species which represent maximum crystal field stablisation energy :-
Answer» `[CO(CN)_(6)]^(-3)` `[Co(C_(2)O_(4))_(3)]^(-3)` `[Ni(H_(2)O)_(6)]^(+2)` Both (1) and (2) ANSWER :A

Discussion

30.	Species acting both as Bronsted acid base is
Answer» `HSO_(4)^(-)` `Na_(2)CO_(3)` `NH_(3)` `OH^(-)` ANSWER :C

Discussion

31.	Species containing carbon with three bonds and an electron are called:
Answer» Carbenes Carbonions Carbonium ions Free radicals Answer :D

Discussion

32.	sp^(3)d- hybridization is possible in
Answer» `SCl_(2)` `SCl_(4)` `SF_(6)` `SeCl_(6)` Answer :B

Discussion

33.	Sp^2 -hybridisation is shown by :
Answer» `BeCl_2` `BF_3` ` NH_3` `XeF_2` ANSWER :B

Discussion

34.	sp^3-hybridisation is important in describing the bonding in :
Answer» `NH_4^+` `C Cl_4` `H_3O^+` All of these Answer :D

Discussion

35.	sp^(2) - Hybridisation is involved in the molecule of
Answer» CO `CO_(2)` `SO_(2)` `SO_(3)` SOLUTION :`CO=SP, CO_(2)=sp, SO_(2)=sp^(3), SO_(3)=sp^(2)`

Discussion

36.	Sources of inert gases are
Answer» Air Natural gas Minerals All the above Answer :D

Discussion

37.	Sorption is the term used when
Answer» ADSORPTION takes PLACE absorption take place both take place DESORPTION takes place Answer :C

Discussion

38.	Sometimes yellow turbidity appears whitepassing H_(2)S gas even in the group II radicals .This is because of
Answer» Sulphate ispresent in themixtureas limpurity GROUP IV radicals areprecipitate assulphides The oxidation of `H_(2)S`GAS by someacidradicals GroupII radicals areprecipitateas hydroxides Answer :C

Discussion

39.	Sometimes yellow turbidity appears while passing H_(2)S gas even in the absence of second group radicals. This is because:
Answer» Sulphur is PRESENT in the mixture as an IMPURITY The fourth group radicals get precipitated as sulphides Of the oxidation of `H_(2)S` to sulphur by some radicals ACTING as oxidant The third group radicals get precipitated as hydroxides. Answer :C

Discussion

40.	Sometimes yellow turbidity appears while passing H_2 S gas even in the absence of II group radicals. This is because
Answer» Sulphur is present in the MIXTURE as impurity IV group radicals are precipitated as sulphides of the oxidation of `H_(2)S` gas by some acid RADICAL III group radicals are precipitated as hydroxide. Solution :`H_2 S + UNDERSET("redical")underset("oxidising")underset("From some")([O]) to underset("sulphur")underset("Colloidal")(Sdarr) _H_(2)O`

Discussion

41.	Sometimes yellow turbidity appears while passing H_2 S gas even in the absence of group II radicals. This is because of
Answer» sulphur is PRESENT in the mixture as impurity group IV radicals are precipitated as sulphides the OXIDATION of `H_2 S` gas by some acid radicals group III radicals are precipitated as hydroxides Solution :TURBIDITY is due to colloidal sulphur FORMED as a result of the oxidation of `H_2S ` by some OXIDISING agent (radicals) present in the mixture .

Discussion

42.	Sometimes yellow turbidity appears o passing H_(2)S gas even in the absence of the second group radicals. This happens because
Answer» Sulphur is present in the MIXTURE as an impurity The FOURTH group radicals are precipitated as SULPHIDES The `H_(2)S` is oxidized by some acid radicals The THIRD group radicals are precipitated SOLUTION :This is due to the precipitation of fourth group radical as sulphides due to high concentration of `S^(2-)` in the solution as a result yellow turbidity is obtained.

Discussion

43.	Sometimesvesselsmade of copperorbronzeshowtracesof greencolur. Thisis due tothe formationof _______
Answer» `Cu(OH)_(2)` `CuCO_(3)` `Cu(OH)_(2)CuCO_(3)` `Cu(OH)_(2) CuSO_(4)` Answer :C

Discussion

44.	Sometimes the behaviour of a compound is explained by assuming that it exists in a world between two or more different possible structures. The phenomenon is called:
Answer» Isomerism Resonance rotation Allotropism Answer :B

Discussion

45.	Sometimes no precipitate is obtained even if group V radicals are present why ?
Answer» Solution :No, precipitate is obtained when the solutio is dilute in dilute solution `(NH_(4))_(2)CO_(3)` hydrolyses to given carbonic acid which is a WEAK ELECTROLYTE. Its ionisation does not produce sufficient `CO_(3)^(2-)` ions concentration to precipitate Ca, Sr and Ba as carbonates `(NH_(4))_(2)CO_(3)+2H_(2)Oto2NH_(4)OH+H_(2)CO_(3)`

Discussion

46.	Sometimes , the colour of photochemical smog becomes brown . The reason for this brown appearance is the excess of
Answer» `NO_2` `SO_2` PAN `CH_4` ANSWER :A

Discussion

47.	Sometimes, it is possible to separate two sulphide ores by using……………….
Answer» SOLUTION :DEPRESSANTS

Discussion

48.	Sometimes it is possible to separate two sulphide ores by adjusting the proportion of oil to water or by using depressant NaCN is added to an ore conaining ZnS and PbS, what is the correct observation?
Answer» NACN PREVENTS PbS from coming to the froth but allows ZnS to come with froth NaCN prevents ZnS from coming to the froth but allows PbS to come with froth NaCN prevents FROTHING of both ZnS and PbS, HENCE no froth is formed NaCN does not act as depressant hence a mixture of PbS and ZnS is found in froth Answer :B

Discussion

49.	Sometimes it happen that when H_(2)S gas is pased into solution in dil.HCI yellowish white turbidity appears what do you conclude ? What precaution are taken to check this turbidity?
Answer» SOLUTION :Thisyellowish white turbidity is due to colloidal sulphur , formed by OXIDATION of `H_(2)S` by theprersence of `NO_(3)^(-)` or `NO_(2)^(-)` or `SO_(3)^(2-)` `H_(2)S+HNO_(3)tounderset(colloidal)(S)` Before passing `H_(2)S GAS solution is boiled so as to decompose these RADICALS.

Discussion

50.	Sometimes indigestion is caused by the secretion of too much hydrochloricx acid in the stomach to eaase the pain caused a table can tbe taken that reacts to reduce the amount of acid present which one amog the folllwoing wuld be inapprapriatefor amanufacturer to inlcude as a major reactant in the tablet?
Answer» OXIDIZING agents are themselves REDUCED Reducing agents gains or appear to gain electrons Reducing agents oxidized oxidizing agents oxidize other substances SOLUTION :Here the reducing agent `FeBr_(3)` GETS oxidized and truns into aqueous solution of `FeCI_(3)`

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Specify the oxidation numbers of the metals in the following coordination entities : [Cr(NH_(3))_(3)Cl_(3)]

Specify the coordination of geometry and hybrization of N and B atoms in 1: 1 comples of BF_(3) and NH_(3)

Specify the oxidation numbers of the metals in the following coordination entities : [CoBr_(2)(en)_(2)]^(+)

Specify the coordination geometry around and hybridisation of N and B atoms in a 1 : 1 complex of BF_(3) and NH_(3)

Specify the coordination geometry and hybridisation around N and B atoms in a 1:1 complex of BF_(3) and NH_(3)

Specificity of enzyme is due to

Specify the coordination geometry around and the hybridisation of N and B atoms in 1 : 1 complex of BF_(3) and NH_(3).

Specific impluse of a rocket and the critical temperature of the fuel reacted in the motor of the rocket has the relationship

Specific reagent for decarboxylation is:

Specific heat of aluminium is 0.214 cal/g^(@)C. Heat required to raise the temperature of 40.0 g of Al from 20^(@) to 30^(@)C is

Specific conductivity of N/35 KCl at 298 K is 0.002768 ohm^(-1) cm^(-1) and it has resistance of 520 ohm. A N/25 solution of a salt kept in the same cell was found to have a resistance of 300 ohm at 298 K. Calculate equivalent conductance of the solution.

Specific gravity of sulphuric acid in lead accumulator is

Specific gravity of slag is :

Specific conductivity of 0.5 mol/dm^(3)" "AgNO_(3) solution at 298 K temperature is 5.76xx10^(-3)" S "cm^(-1), then molar conductivity is. . .

Specific conductivity of a solution

Specific conductivity of 0.1 M NaCl aqueous solution is 1.06xx10^(-2)ohm^(-1)cm^(-1), then what is its molar conductivity in ohm^(-1)cm^(2)mol^(-1) ?

Specific conductance of pure water at 25^(@)C is 0.58 xx 10^(-7) "mho cm"^(-1). Calculate ionic product of water (K_(w)) if ionic conductances of H^(+) and OH^(+) ions at infinite dilution are 350 and 198 mho cm^(2) respectively at 25^(@)C.

Specific conductance of "1 M KNO"_(3) solution is observed to be 5.55 xx 10^(-3)" mho.cm"^(-1). What is the equivalent conductance of KNO_(3) when one litre of the solution is used ?

Specific conductance of 0.1 M sodium chloride solution is 1.06xx10^(-2)ohm^(-1)cm^(-1).Its molar conductance in ohm^(-1)cm^(2)mol^(-1) is

Specific conductance of 0.1 M Nitric acid is 6.3 xx 10^(-2) "ohm"^(-1) cm^(-1) "mol"^(-1) The molar conductance of the solution is

Specific conductance =molar conductance xx cell constant. Is it true or false?

Specific conductance for strong electrolyte on dilution ________

Specific conductance=________x cell constant.

Specific conductivity of a 0.12 normal solution of an electrolyte is 0.023 ohm^(-1)cm^(-1). Determine its equivalent conductivity.

How does specific conductance vary with dilution?

Species present in acidic aq. solution are :

Species which are isoelectronic with OF_(2) is/are

Species which represent maximum crystal field stablisation energy :-

Species acting both as Bronsted acid base is

Species containing carbon with three bonds and an electron are called:

sp^(3)d- hybridization is possible in

Sp^2 -hybridisation is shown by :

sp^3-hybridisation is important in describing the bonding in :

sp^(2) - Hybridisation is involved in the molecule of

Sources of inert gases are

Sorption is the term used when

Sometimes yellow turbidity appears whitepassing H_(2)S gas even in the group II radicals .This is because of

Sometimes yellow turbidity appears while passing H_(2)S gas even in the absence of second group radicals. This is because:

Sometimes yellow turbidity appears while passing H_2 S gas even in the absence of II group radicals. This is because

Sometimes yellow turbidity appears while passing H_2 S gas even in the absence of group II radicals. This is because of

Sometimes yellow turbidity appears o passing H_(2)S gas even in the absence of the second group radicals. This happens because

Sometimesvesselsmade of copperorbronzeshowtracesof greencolur. Thisis due tothe formationof _______

Sometimes the behaviour of a compound is explained by assuming that it exists in a world between two or more different possible structures. The phenomenon is called:

Sometimes no precipitate is obtained even if group V radicals are present why ?

Sometimes , the colour of photochemical smog becomes brown . The reason for this brown appearance is the excess of

Sometimes, it is possible to separate two sulphide ores by using……………….

Sometimes it is possible to separate two sulphide ores by adjusting the proportion of oil to water or by using depressant NaCN is added to an ore conaining ZnS and PbS, what is the correct observation?

Sometimes it happen that when H_(2)S gas is pased into solution in dil.HCI yellowish white turbidity appears what do you conclude ? What precaution are taken to check this turbidity?