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90201.

(A) : Crystalline solids have sharp and chara cteric melting points. (R) : Crystalline solids have definite heat of fusion.

Answer»

Both (A) and (R) are TRUE and (R) is the correct explanation of (A)
Both (A) and (R) are true and (R) is not the correct explanation of (A)
(A) is true but (R) is false
Both (A) and (R) are false

Answer :B
Discussion
90202.

A crystalline solid conducts electricity in aqueous state but behaves as non-conductor in solid state. It shatters when striked with hammer. The solid shows high melting point. The solid is ...

Answer»

GRAPHITE 
NACL 
`H_2O `
`SO_2 `

ANSWER :B
Discussion
90203.

A crystalline solid (A) reacts with hydrogen gas to form a monoatomic gas (B) and a highly associated liquid ( C).(A) is soluble in water and undergoes hydroloysis slowly to form (B),(C ) and a diatomic gas (D).When pure and dry(D) is subjected to a silent electric discharge an another pale blue gas (E) is produced which like (A) also acts a strong oxidising agent.(E) dissolves in potassium hydroxide forming an orange coloured solid which is paramagnetic in nature. (A) reacts with IF_5, SbF_5, PF_5 etc to form the addition compounds. (C ) forms an addition compound (F) with KF with when electrolysed in molten state forms a most reactive gas (G).(B) and (G) (taken in 2:1) ratio when heated in nickel tube at 400^@ C and 6 atm pressure forms (A).The first ionization energy (IE_1) of (B) is fairly close to (D). Which of the following statements is true ?

Answer»

Gas (G) reacts with conc NaOH to form `OF_2`
PALE Blue gas (E) oxidises alkaline KI to `KIO_3`
Pale blue gas (E) in ACIDIC medium reacts with `K_2Cr_2O_7` to form a bright blue coloured compound `(CrO_5)`
(B) and (C ) both

SOLUTION :(A)`F_2` gives `O_2` gas ( C) `H_2O_2` in acidic medium from `CrO_5. "not" O_5`
(B)`KI+3O_3 to KIO_3 + 3O_2`
`underset((A))(XeF_2)overset(H_2)tounderset((B))(Xe)+underset((C ))(2HF)`
`XeF_2+H_2overset(H_2)to+underset((B))(Xe)+underset((C ))(HF)+underset((D))(O_2)`
`underset(( D))(3O_2)hArrunderset((E))(2O_3),5O_3+2KOH to 2KO_3`(orange solid)+`5O_2+H_2O`
`underset(( C))(HF)+KFtoKHF_2("molten")overset("ELECTROLYSIS")tounderset((G))(F_2)`
Discussion
90204.

A crystalline salt when heated beocmes anhydrous and loses 51.2% of its weight. The anhydrous salt on analysis gave the percentage composition as : Mg=20.0%,S=26.66% and O=53.33% Calculate the molecular formula of the anhydrous salt and the crystalline salt. Molecular mass of the anhydrous salt is 120.

Answer»


Solution :Calculate the EMPIRICAL formula of the anhydrous salt. It comes out to be `MgSO_(4).` E.F. mass
MOL. Mass = 120. Hence, MOLECULAR formula = `MgSO_(4)`.
Discussion
90205.

A crystalline solid (A) reacts with hydrogen gas to form a monoatomic gas (B) and a highly associated liquid ( C).(A) is soluble in water and undergoes hydroloysis slowly to form (B),(C ) and a diatomic gas (D).When pure and dry(D) is subjected to a silent electric discharge an another pale blue gas (E) is produced which like (A) also acts a strong oxidising agent.(E) dissolves in potassium hydroxide forming an orange coloured solid which is paramagnetic in nature. (A) reacts with IF_5, SbF_5, PF_5 etc to form the addition compounds. (C ) forms an addition compound (F) with KF with when electrolysed in molten state forms a most reactive gas (G).(B) and (G) (taken in 2:1) ratio when heated in nickel tube at 400^@ C and 6 atm pressure forms (A).The first ionization energy (IE_1) of (B) is fairly close to (D). Which of the following statements is correct for (A) ?

Answer»

The central atom of (A) is `sp^3d` hybridised with three lone pairs of electrons
(A) REACTS with `S_8` molecules in PRESENCE of (C ) to FORM a compound in which the Satom is `sp^3d^2` hybridised
(A) reacts with `SbF_5` as a LEWIS base
All of these

Solution :(A)
(B)`S_8+24XeF_2to24Xe+8SF_6(Stosp^3d^2)`
(C )`XeF_2+SbF_5 to [XeF]^(+)[SbF_6]^(-)`
Discussion
90206.

A crystalline solid (A) reacts with hydrogen gas to form a monoatomic gas (B) and a highly associated liquid ( C).(A) is soluble in water and undergoes hydroloysis slowly to form (B),(C ) and a diatomic gas (D).When pure and dry(D) is subjected to a silent electric discharge an another pale blue gas (E) is produced which like (A) also acts a strong oxidising agent.(E) dissolves in potassium hydroxide forming an orange coloured solid which is paramagnetic in nature. (A) reacts with IF_5, SbF_5, PF_5 etc to form the addition compounds. (C ) forms an addition compound (F) with KF with when electrolysed in molten state forms a most reactive gas (G).(B) and (G) (taken in 2:1) ratio when heated in nickel tube at 400^@ C and 6 atm pressure forms (A).The first ionization energy (IE_1) of (B) is fairly close to (D). Whichof the correct choice for (D) and (E) ?

Answer»

(E) reacts with dry iodine to FORM `I_2O_5`
A filter paper soaked in alcoholic benzidine BECOMES brown when brought in contact with (E)
(D) is prepared by Brin's process
(B) and (C ) both

SOLUTION :(B)test of ozone (not GIVEN by `H_2O_2`)
( C)`2BaO+O_2`(air)`overset(500^@C)to2BaO_2, 2BaO_2 overset(800^@C)toBaO + O_2`
(A)`O_3` forms `I_4O_9` with dry iodine (correct statement )
Discussion
90207.

A crystalline solid (A) reacts with hydrogen gas to form a monoatomic gas (B) and a highly associated liquid ( C).(A) is soluble in water and undergoes hydroloysis slowly to form (B),(C ) and a diatomic gas (D).When pure and dry(D) is subjected to a silent electric discharge an another pale blue gas (E) is produced which like (A) also acts a strong oxidising agent.(E) dissolves in potassium hydroxide forming an orange coloured solid which is paramagnetic in nature. (A) reacts with IF_5, SbF_5, PF_5 etc to form the addition compounds. (C ) forms an addition compound (F) with KF with when electrolysed in molten state forms a most reactive gas (G).(B) and (G) (taken in 2:1) ratio when heated in nickel tube at 400^@ C and 6 atm pressure forms (A).The first ionization energy (IE_1) of (B) is fairly close to (D). Gas (G) is produced by reacting K_2 MnF_6 with:

Answer»

`SbF_5`
`MnF_3`
`KSbF_5`
`MnF_5`

SOLUTION :`2K_2MnF_6 + 4SbF_6 to 4 K [SbF_6] + 2MnF_3 + F_2`
Discussion
90208.

A crystalline salt on being rendered anhydrous loses 45.6% of its weight. The percentage composition of the anhydrous salt is : {:("Aluminium"=10.50%,,"Potassium"=15.1%,),("Sulphur"=24.96%,,"Oxygen"=49.92%.):} Find the simplest formula of the anhydrous and crystalline salt.Find the simplest formula of the anhydrous and crystalline salt.

Answer»

Solution :Step 1. To calculate the empirical formula of the anhydrous salt

Thus, the empirical formula of the anhydrous salt is K Al `S_(2)O_(8)`
Step 2. To calcualte the empirical formula mass of the anhydrous salt.
Empirical formula mass of the anhydrous salt `(KAlS_(2)O_(8))=1xx39.0+1xx27.0+2xx32.0+8xx16.0`
`=258.0u.`
Step 3. To calculate the empirical formula mass of the hydrated salt.
Let the empirical formula mass of the hydrated salt = 100.0 u.
Loss of weight due to dehydration = `45.6%`
`therefore` Empirical formula mass of the anhydrous salt `=100-45.6=54.5u.`
Now, if the empirical formula mass of the anhydrous salt is 54.4, then that of hydrated salt = 100
`therefore `If the empirical formula mass of the anhydrous salt is 258,, that of hydrated salt `=(100)/(54.4)xx258=474.3u.`
Step 4. To calculate the number of molecules of WATER in the hydrate salt.
Total loss in mass due to dehydration =`474.3-258.0=216.3u`
Loss in mass due to one MOLECULE of water= 18.0 u
`therefore"No. of molecules of water in the hydrated SAMPLE"=(216.3)/(18)=12`
Step 5. To calcualte the empirical formula of the hydrated salt.
Empirical formula of the anhydrous salt `=KAlS_(2)O_(8)`
No. of molecules of water of crystallization = 12
`"Empirical formula of the anhydrated salt "=KAlS_(2)O_(8).12H_(2)O`
Discussion
90209.

A crystal was examined with X - rays of wave length 1.53A^(@) with a maximum reflection at 15^(@) 36. What is the interplanar spacing ? If X - rays of wave length 2.29A^(@) was used, what will be angle of reflection?

Answer»

SOLUTION :`3.2 A^(@),28^(@)2`
Discussion
90210.

A crystal system has the following dimensions : a = 0.426nm, b = 0.496nm, c = 0.562 nm and alpha = gamma = 90^(@) and beta cancel(=) 90^(@). This represents

Answer»

MONOCLINIC
TRICLINIC
HEXAGONAL
TETRAGONAL

ANSWER :A
Discussion
90211.

A crystal of lead (II) sulphide has NaCl structure. In this crystal the shortest distance between Pb^(+2) ion and S^(2–) ion is 297 pm. What is the length of the edge of the unit cell in lead sulphide ? Also calculate the unit cell volume.

Answer»


ANSWER :a=`5.94xx10^(-8)`CM,V=`2.096xx10^(022)cm^(-3)`
Discussion
90212.

A crystal of formulaAB_3 has A ions at the cube cornersand B ions at the edge centres . The coordination numbers of A and B are respectively :-

Answer»

6 and 6
2 and 6
6 and 2
8 and 8

ANSWER :C
Discussion
90213.

A crystal of formula AB, has A ions at the cube corners and B ions at the edge centres. The coordination numbers of A and B are respectively

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6 and 2
2 and 6
6 and 6
8 and 8

Answer :A
Discussion
90214.

A crystal of Fe_3O_4 is:

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Paramagnetic
Diamagnetic
Ferromagnetic
None

Answer :C
Discussion
90215.

A crystal may have one or more planes of symmetry as well as one or more axes of symmetry but it has

Answer»

TWO centres of SYMMETRY
no CENTRE of symmetry
ONE centre of symmetry
four centres of symmetry

Answer :C
Discussion
90216.

A crystal may have one or more planes of symmetry as well as one or more axes of symmetry but it has :

Answer»

TWO CENTRES of symmetry
No CENTRE of symmetry
One centre of symmetry
Four centres of symmetry

Answer :C
Discussion
90217.

A crystal is made up of particles A. B and C. A forms fcc packing, B occupies all octahedral voids and C occupies all tetrahedral voids. If all the particles along one body diagonal are removed, then the formula of the crystal would be

Answer»

`ABC_2`
`A_2 B C_2`
`A_8 B_4 C_5`
`A_5 B_4 C_8`

ANSWER :D
Discussion
90218.

A crystal is made of particle X,Y and Z 'X' forms +FCC packing+. 'Y' occupies all the octahedral voids of X and Z occupies all tetrahedral voiods of X. If all the particles along one body diagonal are removed, then the formula of the crystal would be?

Answer»

`XYZ_(2)`
`X_(2)YZ_(2)`
`X_(8)Y_(4)Z_(5)`
none of these

Answer :C
Discussion
90219.

A crystal is formed by two elements X and Y in cubic structure. X atoms are at the corners of a cube while Y atoms are at the face centre . The formula of the compound will be

Answer»

XY
`XY_2`
`X_2Y_3`
`XY_3`

SOLUTION :No. of X atom (at the CORNERS) = `1/8` x 8 =1
No. of Y ATOMS (fcc) = `6xx1/2`=3
HENCE, the formula is `XY_3`
Discussion
90220.

(A) CrO_3, reacts with HCl to form chromyl chloride gas (R) Chromyl chloride (CrO_2Cl_2) has tetra hedral shape

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Both (A) and (R) are TRUE and (R) is the CORRECT EXPLANATION of (A)
Both (A) and (R) are true and (R) is not the correct explanation of (A)
(A) is true but (R) is FALSE
Both (A) and (R) are false

Solution :Both (A) and (R) are true and (R) is not the correct explanation of (A)
Discussion
90221.

(A) Cr^(2+) is reducing while Mn^(3+) is oxidizing when both have d^4 configuration. (R) Configuration of Cr^(2+) changes from d^3 to d^4

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Both (A) and (R) are TRUE and (R) is the CORRECT EXPLANATION of (A)
Both (A) and (R) are true and (R) is not the correct explanation of (A)
(A) is true but (R) is FALSE
Both (A) and (R) are false

Solution :(A) is true but (R) is false
Discussion
90222.

A: Cr_(2)O_(7)^(2-)becomes equilibrium with CrO_(4)^(2-) at PH > 5 R: Cr_(2)O_(7)^(2-) is tetrahedral having Cr -O- Cr angle109º 28

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If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then MARK (1)
If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
If Assertion is true STATEMENT but Reason is false, then mark (3)
If both Assertion and Reason are false statements, then mark (4)

ANSWER :D
Discussion
90223.

Why is Cr^(2+) reducing and Mn^(3+) oxidizing even though both have the same d^(4) electronic configuration.

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Both A & R are TRUE, R is the correct EXPLANATION of A
Both A & R are true, R is not correct explanation of A
A is true, R is FALSE
A is false, R is true

Answer :B
Discussion
90224.

(A) Cr^(+2) is strong reducing agent in aqueous solution. (R) Cr^(+2) cannot liberate H_2 from dilute HCl.

Answer»

Both (A) and (R) are TRUE and (R) is the CORRECT EXPLANATION of (A)
Both (A) and (R) are true and (R) is not the correct explanation of (A)
(A) is true but (R) is FALSE
Both (A) and (R) are false

Solution : (A) is true but (R) is false
Discussion
90225.

(A) Cr^(+3) and Co^(2+) ions have same number of unpaired electrons but the observed magnetic moment of Cr^(3+) is 3.87 B. M and that of Co^(2+) is 4.87 B.M (R) Due to symmetrica electronic configuration there is no orbital motion of unpaired electron in Cr^(3+) ion while appreciable orbital contribution takes place in Co^(2+) ion .

Answer»

Both (A) and (R) are TRUE and (R) is the CORRECT EXPLANATION of (A)
Both (A) and (R) are true and (R) is not the correct explanation of (A)
(A) is true but (R) is FALSE
Both (A) and (R) are false

Solution :Both (A) and (R) are true and (R) is the correct explanation of (A)
Discussion
90226.

A covalently strated host group present in the benzene nucleus is ortho and para-directing, if unsaturated group is present, it is meta-directing. This rule is known as:

Answer»

Vorlander's rule
Crum BROWN GIBSON rule
Korner's rule
Huckel rule

Answer :A
Discussion
90227.

(A) Cr^(+2) is reducing in nature. (R) Half filled t_(zg) level in Cr^(+3) gives greater stability.

Answer»

Both (A) and (R) are TRUE and (R) is the CORRECT EXPLANATION of (A)
Both (A) and (R) are true and (R) is not the correct explanation of (A)
(A) is true but (R) is FALSE
Both (A) and (R) are false

Solution : (A) is true but (R) is false
Discussion
90228.

A covalent molecule AB_(3) has pyramidal structure. The number of lone pair and bond pair electrons in the molecule are respectively.

Answer»

0 and 3
3 and 1
1 and 3
2 and 2

ANSWER :A
Discussion
90229.

A covalent bond is formed between the atoms by the overlapping of orbitals containing :

Answer»

SINGLE ELECTRON
Paired electron
Single electron with PARALLEL spin
Single electron with OPPOSITE spin

Answer :D
Discussion
90230.

A: Coupling reaction is used for the identification of aliphatic primary amine. R: It is called dye test.

Answer»

If both Assertion & Reason are true and the reason is the correct EXPLANATION of the assertion, then mark (1).
If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
If Assertion is true STATEMENT but Reason is false, then mark (3)
If both Assertion and Reason are false statements, then mark (4)

Answer :4
Discussion
90231.

A coupled reaction is takes place as follow A+B to C+D, "" Delta G^(@)= +xkJ D+E to F "" Delta G^(@)= - ykJ for the spontancity of reaction A+B+E to C+F, which of the following is correct ?

Answer»

2x=y
`x LT y`
`x GT y`
`x=(y)xx T Delta S`

Solution :For a spontaneous reaction, `Delta G^(@)` must be NEGATIVE and it can be possible only in this case when `x lt y`
Discussion
90232.

(A): Corrosion involves the oxidation of metal (R): Oxidised form of metal is more stable than metal.

Answer»

Both A & R are true, R is the CORRECT explanation of A
Both A & R are true, R is not correct explanation of A
A is true, R is false
A is false, R is true

Answer :A
Discussion
90233.

A correct statement is

Answer»

`[Co(NH_3)_6]^(+2)` is paramagnetic
`[MnBr_4]^(-2)` is tetrahedral
`[CoBr_2(EN)_2]^(-)` exhibits LINKAGE ISOMERISM .
`[Ni(NH_3)_6]^(+2)` is an INNER orbital complex .

Solution :
Discussion
90234.

A correct electrochemical series (increasing SRP) can be obtained from K. Li, Zn, Fe, H, Ag, Cu, Au by interchanging:

Answer»

K and Li
Zn and Fe
Ag and Cu
Fe and H

Answer :A::C
Discussion
90235.

(A)corey -House reactincan beusedto prepane bothsymmertricalandasymmertricalalkane . ( r) the reactioninvolvestheinteractionbetweenlithiumdialkycopperwithan alkyl halidebothof whichmay containsevenor oddnumberof carbonatoms

Answer»

if both(A) and (R ) are CORRECT and ( R) is thecorrect EXPLANATIONOF the(A)
ifboth(A) and (R ) are correct but ( R) is not thecorrectexplnationof the(A)
if (A) is correct but ( R) is INCORRECT
is (A)in incorrect but( R)is correct

ANSWER :A
Discussion
90236.

A correct electrochemical series can be obtained from K,Ca,Na,Al,Mg,Zn,Fe,Pb,H,Cu,Hg,Ag,Au by interchanging:

Answer»

AL and Mg
Zn and Fe
Zn and Pb
Pb and H

Answer :A
Discussion
90237.

A copper wire is dipped in AgNO_(3) solution kept in beaker A and a silver wire is dipped in a solution of copper suphate kept in beaker B. if standard electrode potential for Cu^(2+)+2e^(-)toCu is +0.34 V and for Ag^(+)+e^(-)toAg is +0.80V, predit in which beeaker the ions present willget reduced?

Answer»

Solution :The PROBABLE reaction in BEAKER A will be
`Cu+2AgNO_(3)toCu(NO_(3))_(2)+2Ag, i.E., Cu+2Ag^(+)toCu^(2+)+2Ag`
`E_(CELL)` for this reaction `=-0.34+0.80=+0.46V` i.e., it is +ve. Hence, `AG^(+)` ions are reduced to Ag.
Discussion
90238.

(A): Copper metal can be extracted by electrolysis even from aqueous solution (R): Copper ions are preferentially reduced to water in aqueous solution

Answer»

Both A & R are true, R is the CORRECT EXPLANATION of A
Both A & R are true, R is not correct explanation of A
A is true, R is false
A is false, R is true

Answer :A
Discussion
90239.

A copper electrode is dipped in 0.1 M copper sulphate solution at 25^(@)C. Calculate the electrode potential of copper. ["Given :" E_(Cu^(2+)|Cu)^(@)=0.34]

Answer»

SOLUTION :GIVEN that
`[CU^(2+)]=0.1M`
`E_(Cu^(2+)|Cu)^(@)=0.34`
`E_("cell")=?`
Cell reaction is
`Cu_((AQ))^(2+)+2e^(-) rarr Cu_((s))`
`E_("cell")=E^(@)-0.0591/nlog""([Cu])/([Cu^(2+)])`
`""=0.34""0.0591/2log""1/0.1`
`""=0.34-0.0296`
`=0.31V`.
Discussion
90240.

A copper coin was electroplated with Zn and then heated at high temperautre until there is a change in colour. What will be the resulting colour ?

Answer»

White
Black
Silver
Golden

Answer :D
Discussion
90241.

A copper coin is completely covered with a gold film and is placed in dilute HNO_(3). This will result in formation of

Answer»

GOLD nitrate
Copper nitrate
Nond of these
Purple of cassius

Solution :NONE of the above. Since, gold is a noble is a metal and COMMON acids do not ATTACK on it if used SINGLY.
Discussion
90242.

A copper cell containing 5% solution of CuSO_(4).5H_(2)O and a silver cell contaning a 2% solution of AgNO_(3) by weight are connectged in series. A current of 0.01 ampere was passed through the cells for 30 minute. What was the ratio of mass of Cu and Ag deposited at the cathode of cell? At. wt. of Cu and Ag arte 63.6 and 108 respectively.

Answer»


ANSWER :`1//3.372 ;`
Discussion
90243.

A copolymer out of the following is

Answer»

PVC
Nylon-6,6
Teflon
Polybutadiene

SOLUTION :Nylon-6,6
Discussion
90244.

A copolymer of isobutylene and isoprene is called:

Answer»

BUTYL RUBBER
buna-S
buna-N
thiokol

Solution :Butyl rubber is a COPOLYMER of ISOBUTYLENE and ISOPRENE.
Discussion
90245.

A copolymerof isobutylene and isopreneis called :

Answer»

BUTYL RUBBER
Buna-S
Buna-N
THIOKOL

ANSWER :A
Discussion
90246.

A copolymer of CH_(2)=CHCl and CH_(2)=CH (OCOCH_(3)) is called

Answer»

SARAN
ORLON
Dynal
Kinoyn

ANSWER :D
Discussion
90247.

A copolymer is obtained by polymerisation of:

Answer»

One type of monomer units
More than one type of monomer units
Either of these
None of these

Answer :B
Discussion
90248.

A coordination compound of cobalt has the molecular formula containing five ammonia molecules, one nitro group and two chlorine atoms for one cobalt atom. One mole of this compound produces three moles of ions in an aqueous solution.The aqueous solution on treatment with an excess of AgNO_(3) gives two equivalents of AgCl as a precipitate. The formula of this complex would be :

Answer»

`[Co(NH_(3))_(4)(NO_(2))CL][(NH_(3))Cl]`
`[Co(NH_(3))_(5)Cl][ClNO_(2)]`
`[Co(NH_(3))_(5)(NO_(2))]Cl_(2)`
`[Co(NH_(3))_(5)][(NO_(2))_(2)Cl_(2)]`

Solution :N//A
Discussion
90249.

A Copolymer is :

Answer»

STYRENE BUTADIENE rubber
Polythene
Terylene
Nylon

Answer :A
Discussion
90250.

A coordination compound with molecular formula CrCl_(3).4 H_(2)O precipitates one mole of AgCl with AgNO_(3) solution. Its molar conductivity is found to be equivalent to two ions. What is the structural formula and name of the compound.

Answer»

Solution :Precipitation of ONE mole of AgCl shows that it has one ionizable Cl (outside the coordination SPHERE). Molar conductivity shows that one mole of the complex produces 2 moles of ions. Hence, the FORMULA is (keeping in mind that coordination number of Cr is 6).
`[Cr(H_(2)O)_(4)Cl_(2)]^(+)Cl^(-)`
NAME : tetraaquadichloridochromium (III) chloride.
Discussion