Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

In a face centred lattice with all the positions occupied by A atoms the body centred octahedral hole in it is occupied by an atom B of an appropriate size for such a crystal, calculate the void space per unit volume of unit cell. Also predict the formula of the compound.

Answer»


ANSWER :`0.75`
2.

In a face centred cubic unit cell of close packed atoms, the radius of atom ( r ) is related to the edge length (a) of the unit cell by the expression

Answer»

`R = ( a)/( sqrt(2))`
`r = ( a)/( 2)`
`r = ( a)/( 2 sqrt(2))`
`r = ( sqrt(3)a)/(4)`

ANSWER :C
3.

In a face centred cubic lattice the number of nearest neighbours for a given lattice point are:

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6
8
12
14

Answer :C
4.

In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions. If one atom of B is missing from one of the face centred points, the formula of the compound is :

Answer»

`A_(2) B_(3)`
`A_(2) B_(5)`
`A_(2)B`
`AB_(2)`

Solution :No. of .A. atoms at corners `= 8 xx ( 1)/( 8 ) =1 `
No. of .B. atoms at FACE CENTRES `= 5 xx ( 1)/( 2) = ( 5)/( 2)`
Formula `=A_(1) B_(5//2) ` or `A_(2) B_(5)`
5.

In a face centred cubic lattice, a unit cell is shared equally by low many unit cells ?

Answer»

8
4
2
6

Solution :Infcc, a UNIT CELL is SHARED equally by six unit cells.
6.

In a face centred cubic lattice, a unit cell is shared equally by how many unit cells ?

Answer»

2
4
6
8

Solution :Each UNIT CELL is SHARED by 6 unit CELLS
7.

In a face-centred cubic cell, an atom at the face centre is shared by:

Answer»

6 UNIT CELLS
1 unit cells
4 unit cells
2 unit cells

ANSWER :D
8.

In a face centred cubic arrangement of A and B atoms whose A atoms are at the corner of the unit cell and B atoms at the face centres: One of the A atom is missing from one corner in unit cell . The simplest formula of compund is :

Answer»

`A_7B_3`
`Ab_3`
`A_7B_24`
`A_7/8B_3`

ANSWER :C
9.

In a face centred cubic arrangement of A and B atoms in which ‘A’ atoms are at the corners of the unit cell and .B. atoms are at the face centers, one of the ‘A’ atoms is missing from one corner in the unit cell. The simplest formula of the compound is

Answer»

`AB_(3)`
`A_(7)B_(24)`
`A_(7)B_(8)`
`A_(7)B_(8)`

SOLUTION :NUMBER of A atoms at the corners = `7 xx (1)/(8)= (7)/(8)`
No. of B atoms at face centres = `6 xx (1)/(2) = 3`
RATIO of `A: B = (7)/(8) : 3 = 7:24`
`:.` Formula of compound is `A_(7)B_(24)`
10.

In a face centred cubic arrangement of A and B atoms, A atoms are at the corners of the unit cell and B atoms at theface centres. One of the A atom is missing from one corner in the unit cell. The simplest formula of the compound is

Answer»

`A_(7)B_(3)`
`AB_(3)`
`A_(7)B_(3)`
`A_(7//8)B_(3)`

Solution :If ONE atom (A) is missing from one corner, no of ATOMS A in unit CEL `=7xx1/8=7/8`
no. of atoms B in unit cell `=6xx1/2=3`
`A:B=7/8j:3`.so, simplest FORMULA is `A_(7)B_(24)`.
11.

In a face centered unit cell (fcc) the number of atoms present

Answer»

4
2
3
5

Answer :A
12.

In a Face centered Cubic lattice, the packing fraction is

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0.52
0.68
0.74
0.65

Answer :C
13.

In a face centred cubic arrangement of A and B atoms whose A atoms are at the corner of the unit cell and B atoms at the face centred. One of the A atom is missing from one corner in unit cell. The simplest formula of compound is :

Answer»

`a_(7)b_(8)`
`a_(7)b_(3)`
`ab_(3)`
`a_(7)b_(24)`

Answer :D
14.

In a dry cell , zinc container is protected from the atmosphere by covering it with

Answer»

a METAL cap
paste of `NH_(4)Cl` and `ZnCl_(2)`
cardboard
metal cap

Answer :C
15.

In a Duma's method 0.3g of an organic compound gave 50ml of nitrogen collected at 27^(@)C and 715mm pressure . The percentage of N is (aqueous tension at 27^(@)C=15mm) :

Answer»

<P>`19.46%`
`21.46%`
`17.46%`
`36.64%`

SOLUTION :VAPOUR pressure of GAS `=715-15`
`=700mm`
To calculate the volume of `N_(2)` at S.T.P
`{:(V_(1)=50mL,V_(2)=?),(p_(1)=700mm,p_(2)760MM),(T_(1)=300K,T_(2)=273K):}`
Applying `(p_(1)V_(1))/(T_(1))=(p_(2)V_(2))/(T_(2))`
or `V_(2)=(p_(1)V_(1)T_(2))/(p_(2)T_(1))`
`:.V_(2)=(700xx50xx273)/(760xx300)`
`=41.9mL`
`22400mL` of nitrogen at S.T.P.weigh `=28g`
`41.9mL` of nitrogen at S.T.P.weigh
`=(28xx41.9)/(22400)`
`=0.0524g`
Percentage of nitrogen
`=(0.0524)/(0.3)xx100=17.46%`
16.

In a dry cell the depolarizer is :

Answer»

`MnO_2`
`ZN`
CHARCOAL POWDER
`NH_4Cl`

ANSWER :A
17.

In a determination of P an aqueous solution of NaH_(2)PO_(4) is treated with a mixture of ammonium and magnesium ammonium phosphate Mg(NH_(4))PO_(4).6H_(2)O. This is heated and decomposed to magnesium pyrophosphate, Mg_(2)P_(2)O_(7) which is weighed . A solution of NaH_(2)PO_(4) yeilded 1.11 g of Mg_(2)P_(2)O_(7). What weight of NaH_(2)P_(2)O_(7) was present originally ? (P = 31)

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ANSWER :`1.20` GM
18.

In a double sulphate salt K_(2)SO_(4)Al_(2)(SO_(4))_(3)4xx xH_(2)O. The value of x is

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SOLUTION :(6) DOUBLE sulphate salts are `K_(2)SO_(4). Al_(2)(SO_(4))_(3).24H_(2)O`.
`:. K_(2)SO_(4).Al_(2)(SO_(4))_(3).6xx4H_(2)O`.
19.

In a dilute aqueous H_(2)SO_(4), the complex disaquadioxalato ferrate (II) is oxidised by MnO_(4)^(-). For this reaction, the ratio of the rate of change of [H^(+)]. For this reaction, the ratio of the rate of change of [H^(+)] to the rate of change on [MnO_(4)^(-)] is:

Answer»


Solution :The BALANCED chemical equation is:
`MnO_(4)^(-)+[Fe(H_(2)O)_(2)(C_(2)O_(4))_(2)]^(2-) + 8H^(+) to MN^(2+) + Fe^(3+) + 4CO_(2)+H_(2)O`
`r_(H^(+))/r_(MnO_(4)^(-))=8/1`
20.

In a cyclotrimetaphosphoric acid molecule, how many single and double bonds are present

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3 double bonds , 9 single bonds
6 double bonds , 6 single bonds
3 double bonds , 12 single bonds
Zero double bonds , 12 single bonds

Solution :REFER to the STRUCTURE of cyclotrimetaphoric acid. No. of P = O double bonds = 3 and No. of P-O single bonds = 9.
21.

In a cyclotrimetaphosphoric acid molecule, how many P-Osingle and double bonds are present ?

Answer»

3 DOUBLE bonds, 9 single bonds
6 double bonds, 6 single bonds
3 double bonds , 12 single bonds
ZERO double bonds, 12 single bonds

Solution :The structure of cyclotrimetaphosphoric acid is :
22.

In a cubic unit cell:

Answer»

a = B = c, `alpha = BETA = GAMMA = 90^(@)`
a = b = c, `alpha = beta = gamma = 120^(@)`
a ne b ne c, `alpha ne beta ne gamma = 90^(@)`
a = b ne c, `alpha = beta ne gamma = 90^(@)`

ANSWER :A
23.

In a cubic structure, atoms of 'X' occupy the comers, atoms of 'Y' occupy the centre of the body and atoms of 'Z' occupy the centres of all six faces. Write the composition of the unit cell.

Answer»

Solution :Position of .X. is comers of CUBE. Number of comers `= 8 `
Contribution of ATOM as .X. to unit cell `= 1//8`. Number of atoms of `.X. = 8 xx 1//8 = 1`
Position of .Y. is CENTRE of the body. Number of body CENTRES `= 1`
Contribution of atom of .Y. to unit cell = 1. Number of atoms of `.Y. = 1 xx 1 = 1`
Position of .Z. is centre of the face. Number of face centres ` = 6`
Contribution of atom of .Z. to unit cell `= 1//2`. Number of atoms of `.Z. = 6 xx 1//2 = 3`
The composition of unit cell containing atoms of X, Y and `Z = XYZ_3`
24.

In a cubic type unit cell, atoms of A are at centre and corners of the cube. Atoms of B are at one half faces of the cube. What is the simplest formula of the compound?

Answer»

SOLUTION :NUMBER of atoms of A = `8 XX 1/8+1xx1=1+1=2`
Number of atoms of B = `3 xx 1/2 = 3//2`
`:.` Simple formula of the COMPOUND `A_2B_(3//2) = A_4B_3`
25.

In a cubic type unit cell, A atoms are at one half faces, while B atoms are at the corners of the cube. Calculate the formula of the compound.

Answer»

SOLUTION :NUMBER of atoms of A : (3 faces, `1/2` fraction), i.e., `3 xx 1/2=3/2`
Number of atoms of B : (8 corners, `1/8` fraction), i.e., `8 xx 1/8 =1`
So, the formula of the compound = `A_(3//2) B = A_3B_2`
26.

In a cubic structure, atoms of 'X' occupy the corners, atoms of 'Y' occupy the centre of the body and atoms of 'Z' occupy the centres of all six faces. Write the composition of the unit cell.

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Solution : Position of ‘X’ is CORNERS of cube. Number of corners = 8 Contribution of atom as ‘X’ to unit cell = 1/8 Number of atoms of ‘X’ = 8 X 1/8 = 1 Position of ‘Y’ is centre of the body. Number of body centres = 1 Contribution of atom of ‘Y’ to unit cell = 1 Number of atoms of ‘ Y’ = 1 X 1 = 1 Position of ‘Z’ is centre of the face. Number of face centres = 6 Contribution of atom of ‘Z’ to unit cell = 1/2 Number of atoms of ‘Z’ = 6 X 1/2 = 3 The composition of unit cell CONTAINING atoms of X, Y
27.

In a cubic packed structure of mixed oxides , the lattice is made up of oxide lois one fifth of retrahedral voids are occupied by cation of a while one half of the formula of the oxide is

Answer»

`X_(5)Y_(4)O_(10)`
`X_(4)Y_(5)O_(10)`
`XY_(2)O_(4)`
`X_(2)Y_(4)`

ANSWER :B
28.

In a cubic crystal of CsCl (density = 3.97 gm//cm^(3)) the eight corners are occupied by Cl^(–) ions with Cs+ ions at the centre. Calculate the distance between the neighbouring Cs^(+) and Cl^(–) ions.

Answer»

Solution :`3.94=(1XX(M)/(N_(A)))/(a^(3))=(168.5)/(6.022xx10xxa^(3))`
`impliesa^(3)=(168.5)/(6.022xx10^(-23)xx3.97)`
`a^(3)=7.05xx10^(-23)CM^(3)`
`a=4.13xx10^(-8)` cm
`r_(+)+r_(-)=(asqrt(3))/(2)=3.577xx10^(-8)`
3.577xx10^(-10) cm`
=3.577 Å
29.

In a cubic crystal of CsCl (density = 3.97 gm/cm^(3)) the eight corners are occupied by Cl^(–) ions with Cs^(+) ions at the centre. Calculate the distance between the neighbouring Cs^(+) and Cl^(–) ions.

Answer»


ANSWER :3.57 Å
30.

In a cubic closed packed structure of mixed oxides the lattice is made up of oxide ions, one eighth of tetrahedral voids are occupied by divalent ions (A^(2+)) while one half of the octahedral voids occupied trivalent ions (B^(3+)). What is the formula of the oxide ?

Answer»

`A_(2)BO_(4)`
`AB_(2)O_(3)`
`A_(2)BO_(3)`
`AB_(2)O_(4)`

ANSWER :D
31.

In a cubic crystal anions are arranged in fcc arrangement and the cations occupy all the octahedral voids and half the tetrahederal voids. The ratio of the cations and anions in the crystal is

Answer»

`1:1`
`2:1`
`1:2`
`3:2`

Solution :For fcc arrangement
No. of anion = 4
Fro each atom, there is one octahedral site and 2 TETRAHEDRAL sites. THEREFORE, for 4 anions, there will be 4 octahedral sites and 8 tetrahedral sites.
No. of CATIONS `= 4 XX 1 + 8 xx ( 1)/( 2) = 8`
Ratio of cation and anion `= 8 : 4 ` or `2:1`
32.

In a cubic closed packed structure of mixed oxides the lattice is made up of oxide ions, one eighth of tetrahedral voids are occupied by divalent ions (A2^(+)) while one half of the octahedral voids occupied trivalent ions (B3^(+)). What is the formula of the oxide?

Answer»


ANSWER :`AB_(2)O_(4)`
33.

In a cubic closed packed structure of mixed oxide, the oxide ions are in CCP arrangement 1/6 of tetrahedral voids are occupied by cations A and 1/2 of octahedral voids are occupied by cations B. The formula of the oxide is

Answer»

`abo_(2)`
`a_(2)bo_(2)`
`a_(2)b_(2)O`
`a_(2)b_(3)o_(6)`

ANSWER :D
34.

In a cubic close packing of spheres in there dimensions the coordination number of each sphere is:

Answer»

6
9
3
12

Answer :D
35.

In a cubic close packed structure the number of nearest neighbours for a given lattice point is

Answer»

6
8
12
14

Answer :C
36.

In acrystallinesubstanceatoms A occupycornersof a cubewhile atom B occupiesbodycentres .Whatis the formula of thesubstance?

Answer»


ANSWER :AB
37.

In a crystalline solid, anions B are arranged in ccp lattice and cations A occupy 50% of the octahedral voids and 50% of the tetrahedral voids. What is the formula of the solid

Answer»

AB
`A_(3)B_(2)`
`A_(2)B_(2)`
`A_(2)B_(3)`

ANSWER :B
38.

In a crystal of compound having molecular formula X_2 Y_3, Y atoms are arranged in CCP, then what fraction of tetrahedral voids will be covered by X atoms ?

Answer»

`1/3`
`1/4`
`2/3`
`3/4`

ANSWER :A
39.

In a crystal, the atoms are located at the position of……potential energy.

Answer»

Zero
Infinite
Minimum
Maximum

Answer :C
40.

In a crystal some ions are missing from normal sites This is an example of:

Answer»

F-centres
Interstitial DEFECT
Frenkel defect
SCHOTTKY defect

Answer :D
41.

In a crystal AB, which of the following crystal systems will have parameters, a ne b ne c and alpha = beta = gamma = 90^(@) ?

Answer»

CUBIC
Orthorhombic
Monoclinic
TRICLINIC

ANSWER :B
42.

In a coordination compound, if the metal ion has a secondary valence of six, it has an…………. Geometry.

Answer»


ANSWER :OCTAHEDRAL
43.

In a covalent bond, a difference of 1.7 in the electronegativities of the combing atoms produces an ionic character of about __________.

Answer»

`50%`
`30%`
`90%`
`70%`

ANSWER :A
44.

In a container of constant volume at a particular temperature N_2 and H_2 are mixed in the molar ratio of 9:13. The following two equilibria are found to be coexisting in the container N_2(g)+3H_2(g)hArr2NH_3(g) N_2(g)+2H_2(g)hArrN_2H_4(g) The total equilibrium pressure is found to be 3.5 atm while partial pressure of NH_3(g) and H_2(g) are 0.5 atm. and 1 atm respectively.Calculate of equilibrium constants of the two reactions given above.Give your answer as (Kp_1 + Kp_2)xx10

Answer»

<P>

SOLUTION :Let the initial partial pressures of `N_2` and `H_2` be 9P and 13 P respectively.
`{:(N_2(g)+,3H_2(g)hArr,2NH_3(g)),(2P-y-x,13P-3x-2y,2x):}`
`{:(N_2(g)+,2H_2(g)hArr,N_2H_4(g)),(2P-y-x,13P-3x-2y,y):}`
Total PRESSURE=`P_(N_2)+P_(H_2)+P_(NH_3)+P_(N_2H_4)`=3.5 atm
=(9P-x-y)+(13 P-3x-2y)+2x+y=3.5 atm ...(i)
`P_(NH_3)=2 x=0.5` atm ...(2)
`P_(H_2)=(13P-3x-2y)=1` atm
from (1)`implies` (9P-x-y)+1 atm +0.5 +y=3.5
`implies` (9P-x)=2 atm
so 9P=2.25
P=0.25 atm from (3)equation 2y=1.5
y=0.75 atm
so `P_(N_2)`=9P-x-y=1.25 atm
`P_(H_2)`=9P-x-y=1.25 atm
`P_(H_2)`=1atm
`P_(NH_3)`=0.5 atm
`P_(H_2H_4)=`0.75 atm
So,
`K_(P_1)=(P_(NH_3)^2)/(P_(H_2)^3.P_(N_2^2))=(0.5xx0.5)/(1xx1xx1xx1.25)=0.2 atm^(-2)`
`K_(P_2)=(P_(N_2H_2))/(P_(N_2).P_(H_2^2))=(0.75)/(1xx1xx1.25)=0.6 atm^(-2)`
`P_(A_2C_2)`=y-z=1-`1/4=3/4` atm
45.

In a container of 10 L volume, 20 g O_2(g) and 2.8 g CO(g) are taken at a total pressure of 2 atm and (27 ^0 C). Partial pressure and partial volume occupied by oxygen gas in container respectively are

Answer»

`[50/29 ATM]` ,`[250/29]L`
`[17/50 atm]` ,`[250/29]L`
`[14/50 atm]` ,`[40/29]L`
`[50/29 atm]` ,`[100/29]L`

ANSWER :4
46.

In a constant volume calorimeter 5g of a gas with molecular weight 40 was burnt in excess of oxygen at 298 K.the temperature of the calorimeter was found to increase from 298 K to 298.75 K due to combustion process.Given that the heat capacity of the calorimeter is 2.5 kJ K^(-1),a numerical value for the DeltaU of combustion of the gas in kJ mol^(-1) is

Answer»

15
12
90
8

Answer :A
47.

In a constant volume calorimeter, 3.5g of a gas with molecular weight 28 was burnt in excess oxygen at 298.0 K. The temperature of the calorimeter was found to increase from 298.0K to 298.45 K due to the combustion of the gas in kJ mol^(-1) is

Answer»

<P>

Solution :`n=(3.5)/(28)`
`DeltaT=T_(2)-T_(1)=298.45-298=0.45`
`C_(P)=C_(V)+R=2500+8.314=2508.314 JK^(-1)`
`Q_(P)=C_(P)DeltaT=1128.74 J`
`DeltaH=(Q_(P))/(n)=(1128.74)/(3.5//28)`
implies 9030 J `mol^(-1)`=9.030 kJ `mol^(-1)` = 9 kJ `mol^(-1)`.
48.

In a constant volume calorimeter, 3.5 g of a gas with moleular weight 28 was burnt in excess oxygen at 298.0 K . The temperature of the calorimeter was found to increase from 298.0 K to 298.45 K due to the combustion process. Given that the heat capacity of the calorimeter is 2.5 KJK^(-1), the numerical value for the enthalphy of combustion of the gas in KJ mol^(-1) is .

Answer»


Solution :`N=(3.5)/(28)`
`DeltaT = T_(2)- T_(1) = 298.45 - 298 = 0.45`
`C_(V)=2.5KJ K^(-1) = 2500 JK^(-1)`
`C_(p) = C_(v) + R = 2500 + 8.314 = 2508.314 JK^(-1)`
`Q_(p) = C_(p)DeltaT = 1128.74 J`
`DELTAH = (Q_(p))/(n) = (1128.74 )/(3.5//28) = 9030 J mol^(-1) = 9.030 KJ mol^(-1) = 9 KJ mol^(-1).`
49.

In a constant volume calorimeter, 3.5 g of a gas with molecular weight 28 was burnt in excess oxygen at 298.0 K. The temperature process. Given that the heat capacity of the calorimeter is was found to increase from 298.0 K to 298.45 K due to the combustion process. Given that the heat capacity of the calorimeter is 2.5 kJ K^(-1), the numerical value for the enthalpy of combustion of the gas in kJ "mol"^(-1) is

Answer»


Solution :`q=ms DeltaT=2.5xx0.45=1.125 KJ rArr DeltaE=-1.125/3.5xx28=-9" kJ/mole"`
`|DeltaE|=9" kJ/mole"`
[Since `DELTAH=DeltaE+Deltan_(g) RT` to determine `DeltaH` from `DeltaE` we MUST know `Deltan_(g)` (i.e. Chemical reaction or Compound) which is not given therefore having no other option answer is 9]
50.

In a constant volume calorimeter, 3.5 g of a gas with molecular weight 28 was burnt in excess oxygen at 298.0 K. The temperature of the calorimeter was found to increase from 298.0 K to 298.45 K due to the combustion process. Given that the heat capacity of the calorimeter is 2.5 kJ K^(-1), find the numerical value for the enthalpy of combustion of the gas in kJ mol^(-1)

Answer»

Solution :Heat of combustion of 3.5 G of the gas = Heat TAKEN by the calorimeter= 2.5 (298.45 – 298.0) kJ
`9kJ "MOL"^(-1)`