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86001.

According to VSEPR model, molecules adopt geometries in which their valence electron pairs position themselves as far from each other as possible. The VSEPR model considers double and triple bonds to have slightly greater repulsive effects than single bonds because of the repulsive effect of pi -electrons. However the lone pair creates the maximum repulsive effect. Select the incorrect statement with respect to SO_(2)Cl_(2) molecule :

Answer»

It gives `H_(2)SO_(4)` and HCl on hydrolysis at room temperature
It has TWO `d PI - p pi` bonds between S and O bonded atoms
It is a polar molecule
None

Solution :
Discussion
86002.

According to VSEPR model, molecules adopt geometries in which their valence electron pairs position themselves as far from each other as possible. The VSEPR model considers double and triple bonds to have slightly greater repulsive effects than single bonds because of the repulsive effect of pi -electrons. However the lone pair creates the maximum repulsive effect. Which of the following does not represent the isostructural pair ?

Answer»

`SF_(5)^(-) and IF_(5)`
`ClO_(2)F_(3) and SOF_(4)`
`SeF_(3)^(+) and XeO_(3)`
None

Solution :
Discussion
86003.

According to VSEPR model, molecules adopt geometries in which their valence electron pairs position themselves as far from each other as possible. The VSEPR model considers double and triple bonds to have slightly greater repulsive effects than single bonds because of the repulsive effect of pi -electrons. However the lone pair creates the maximum repulsive effect. Which of the following statement is false ?

Answer»

`SbF_(4)^(-) and SF_(4)` are isostructural
In `IOF_(5)` the hybridization of central atom is `sp^(3)d^(2)`
Double bond(s) in `SOF_(4) and XeO_(3)F_(2)`, is / are OCCUPYING equatorial position(s) of their respective geometry
none of these

Solution :
Discussion
86004.

According to V.B.T., atoms of element form bond only to pair up their unpaired electrons present in ground state or excited state. This pairing of unpaired electron will take place by overlapping of orbitals each one having one unpaired electron with opposite spin. Which of the following combination of orbitals does not from any type of covalent bond (if z-axis is molecular axis)?

Answer»

<P>`p_(s)+p_(Z)`
`p_(y)+p_(y)`
`s+p_(y)`
`s+s`

ANSWER :C
Discussion
86005.

According to V.B.T., atoms of element form bond only to pair up their unpaired electrons present in ground state or excited state. This pairing of unpaired electron will take place by overlapping of orbitals each one having one unpaired electron with opposite spin. Which of the following orbital combination does not form pi-bond ?

Answer»

`p_(X)+p_(x)` SIDEWAYS overlapping
`d_(x^(2)-y^(2))+p_(y)` sideways overlapping
`d_(XY)+d_(xy)` sideways overlapping
`d_(yz)+p_(y)` sideways overlapping

Answer :B
Discussion
86006.

According to V.B.T., atoms of element form bond only to pair up their unpaired electrons present in ground state or excited state. This pairing of unpaired electron will take place by overlapping of orbitals each one having one unpaired electron with opposite spin. Which of the following orbital cannot form delta-bond ?

Answer»

`d_(x^(2)-y^(2))` orbital
`d_(xy)` orbital
`d_(x^(2))` orbital
`d_(ZX)` orbital

Answer :C
Discussion
86007.

According to VBT any covalent bond will be formed by overlapping of atomic orbitals of bonded atoms provided atomic orbitals must be half-filled and electrons be in opposite spin. According to type of overlapping covalent bonds can be classified as (a) sigma-bond (b) pi-bond (c ) delta-bond : The combination of orbital that can not produce non-bonding molecular orbital is (internuclear axis is z-axis ) :

Answer»

`p_(y)+d_(x^(2)-y^(2))`
`p_(z)+d_(yz)`
`s+d_(XZ)`
`d_(xy)+d_(xy)`

Solution :`(a) implies p_(y)+d_(x^(2)-y^(2))` : can produce non-bonding if inter-nuclear axis is either x,y or z-axis
`(b) implies p_(z)+d_(yz)` : can produce non-bonding if inter-nuclear axis is either x,y or z-axis
(c )` implies s+d_(xz)` : will always form non-bonding inrrepective of inter-nuclear axis
(d) `implies d_(xy)+d_(xy)` : either form `pi` bond if inter-nuclear axis is `x//y` axis or can ALSO form `delta`-bond if inter nuclear axis is z-axis.
Discussion
86008.

According to VBT any covalent bond will be formed by overlapping of atomic orbitals of bonded atoms provided atomic orbitals must be half-filled and electrons be in opposite spin. According to type of overlapping covalent bonds can be classified as (a) sigma-bond (b) pi-bond (c ) delta-bond : If F_(2)C_(1)=C_(2) " part of " F_(2)C_(1)=C_(2)=C_(3)=C_(4)F_(2) lies in yz-plane, then incorrect statment is :

Answer»

<P>NODAL plane of `PI`-bond between `C_(1) and C_(2)` LIES in yz-plane, FORMED by sideways overlapping of `p_(x)`-orbitals
Nodal plane of `pi`-bond between `C_(2) and C_(3)` lies in xz-plane, formed by sideways overlapping of `p_(y)`-orbitals
Nodal plane of `pi`- bond between `C_(3) and C_(4)` lies in yz-plane, formed by sideways overlapping of `p_(y)` -orbitals
Nodal plane of `pi`-bond between `C_(2) and C_(3)` lies in xy-plane, formed by sideways overlapping of `p_(x)` - orbitals

Solution :Nodal plane of `pi` - bond between `C_(3) and C_(4)` lies in yz-plane formed by sideways overlapping of `p_(x)` - orbitals.
Discussion
86009.

According to VBT any covalent bond will be formed by overlapping of atomic orbitals of bonded atoms provided atomic orbitals must be half-filled and electrons be in opposite spin. According to type of overlapping covalent bonds can be classified as (a) sigma-bond (b) pi-bond (c ) delta-bond : Which of the following set of orbitals does not produce nobal plane in xz-plane ?

Answer»

<P>`d_(YZ)+d_(yz)`
`d_(XY)+d_(xy)`
`p_(y)+d_(xy)`
NONE of these

Solution :
Discussion
86010.

Accordingto van'tHolf - Avogadro's lawvolumeoccupied bya solution is_____.

Answer»

directlyproportional tomassof SOLUTE
inversely PROPORTIONAL to MASSOF solute
directlyproportionalto numberofmoleculesof solute
inverselyproportionalto numberofmoleculesof solute

ANSWER :C
Discussion
86011.

According to Van't Hoff -Avogadro's law volume occupied by solution is

Answer»

directly proportional to MASS of SOLUTE
inversely proportional to mass of solute
directly proportional to number of MOLECULES of solute of
inversely proportional to number of molecules of solute

Answer :C
Discussion
86012.

According to the third law of thermodynamics which one of the following quantities for a perfectly crystalline solid is zero at absolute zero?

Answer»

Free energy
Entropy
Enthalpy
Internal energy

Solution :Entropy is the degree of randomness or disorder of the system. When the TEMPERATURE of the system is zero kelvin, then all the MOTION of molecules ceases. According to third law of THERMODYNAMICS "At absolute zero the entropy of a PERFECTLY crystalline substance is TAKEN as zero".
Discussion
86013.

According to the solubility curve shown, how many grams of solute can be recrystallized when 20 mL of a saturated solution at 60^(@)C are cooled to 0^(@)C ?

Answer»

`7.0`
12
25
35

Answer :A
Discussion
86014.

According to the reaction PbCl_(2) = Pb^(2) + 2Cl^(-), the solubility coefficient of PbCl_(2) is

Answer»

`[PB^(2+)] [Cl^(-)]^(2)`
`[Pb^(2+)] [Cl^(-)]`
`[Pb^(2+)]^(2) [Cl^(-)]`
NONE of these

Solution :Solubility coefficient `= [Pb^(2+)] [Cl^(-)]^(2)`.
Discussion
86015.

According to the IUPAC system CH_(3)CH_(2)COCl is named as :

Answer»

CHLOROPROPANE
Propanoyl CHLORIDE
Chloropropanyl
Proponyl chloride.

ANSWER :B
Discussion
86016.

According to the ideal gas laws, the molar volume of a gas is given by :

Answer»

22.4 litre
`(RT)/P`
`(8RT)/(PV)`
`(RT)/(PV)`

Answer :B
Discussion
86017.

According to the following informatin, in what physical state(s) does bromine exist at -7.4^(@)C and 400mm Hg? [ Triple point -7.3^(@)C, 44 mm Hg Liquid density 3.1 g cm^(-3), Solid density 3.4 g. cm^(-3)]

Answer»

SOLID only
LIQUID only
Liquid and solid only
Gas, liquid and solid

Answer :A
Discussion
86018.

According to the following diagram, which of the following option is correct?

Answer»

B can reduce `CO_(2)` above `800^(@)C`
C can reduce `AO_(2)` below `600^(@)C`
Both B and A can reduce CO2 above `400^(@)C`
A can reduce both `BO_(2)` and `CO_(2)` below `600^(@)C`

Solution :(i) `A+BO_(2)rarrAO_(2)+B,""Delta_("rxn")G^(@)`
(ii) `A+CO_(2)rarrC+AO_(2),""Delta_("rxn")G^(@)`
Below `600^(@)C, Delta_("rxn")G^(@)` for both the reaction (i) and (ii) is negative.
Discussion
86019.

According to the first law of thermodynamics which of the following quantities represents change in a state function

Answer»

`q_(REV)`
`q_(rev)-w_(rev)`
`q_(rev)//w_(rev)`
`q_(rev) + w_(rev)`

SOLUTION :`DELTAE=q+W, DeltaE` is a STATE function.
Discussion
86020.

According to the equation, C_6H_6(l)+15/2O_2(g)rarr3H_2O(l)+6C_2(g) triangleH=-3264.4kJ/mol, the energy evolved when 7.8 g of benzene is burnt in air will be:

Answer»

163.22 kJ/mol
326.4 kJ/mol
32.64 kJ/mol
3.264 kJ/mol

Answer :B
Discussion
86021.

According to the Crystal Field Theory, the energy of d_(xy) orbital is lower than d_(x^(2)-y^(2)) in an octahedral complex because

Answer»

the `d_(xy)` orbital near the LIGANDS
the REPULSION between the `d_(xy)` electrons and ligands electrons is LESS than that between `d_(X^(2)-y^(2))` and ligands electrons.
the repulsion between the `d_(xy)` electrons and ligands electrons is more than that between `d_(x^(2)-y^(2))` and ligands electrons.
the `d_(x^(2)-^(2))` orbital is away the ligands.

Answer :B
Discussion
86022.

According to the Dalton's atomic theory in a chemical change :

Answer»

ATOMS are destroyed
atoms are MADE into NEW and DIFFERENT kind
Atoms are created
atoms are rearranged

Answer :D
Discussion
86023.

According to the collision theory, only the effective collisions among the reacting species result in the products. In order that the collisions may be effective, the reacting species must have energy equal to or more than a certain minimum energy called threshold energy (E^(@)). Extra energy which has be supplied to the reactants to make collisions effective is known as activation energy (E_(a)). This is related to reaction rate with the help of Arrhenius equation, k=Ae^(-Ea//RT) The equation also helps in calculating the activation energy for a reaction at a specific temperature. In general, the rate of reaction is inversely proportional to the activation energy required. Consider the reaction A to 2B + C, DeltaH=-15 kcal. The energy of activation of backward reaction is 20 kcal mol^(-1). In presence of the catalyst, the energy causes the rate of the reaction to increase by the number of times equal to

Answer»

`e^(3.5)`
`e^(2.5)`
`e^(-2.5)`
`e^(2.303)`

SOLUTION :b) `E_(a)(f) - E_(ab) = DeltaH=-15 kcal`
`E_(af) = -15 + 20=5kcal`
`(k("catalyst"))/(k) = e^(E_(a)-E_(a)("catalyst"))/(RT) = e^((5-3) XX 10^(3))/(2 xx 400)`
`=e^((2 xx 1000))/((2xx400))=e^(2.5)`
Discussion
86024.

According to the collision theory, only the effective collisions among the reacting species result in the products. In order that the collisions may be effective, the reacting species must have energy equal to or more than a certain minimum energy called threshold energy (E^(@)). Extra energy which has be supplied to the reactants to make collisions effective is known as activation energy (E_(a)). This is related to reaction rate with the help of Arrhenius equation, k=Ae^(-Ea//RT) The equation also helps in calculating the activation energy for a reaction at a specific temperature. In general, the rate of reaction is inversely proportional to the activation energy required. The chemical reactions in which the reactants require high amount of activation energy are generally.

Answer»

SLOW
fast
instaneous
spontaneous

Solution :a) slow reactions REQUIRE HIGH activation ENERGY.
Discussion
86025.

According to the collision theory, only the effective collisions among the reacting species result in the products. In order that the collisions may be effective, the reacting species must have energy equal to or more than a certain minimum energy called threshold energy (E^(@)). Extra energy which has be supplied to the reactants to make collisions effective is known as activation energy (E_(a)). This is related to reaction rate with the help of Arrhenius equation, k=Ae^(-Ea//RT) The equation also helps in calculating the activation energy for a reaction at a specific temperature. In general, the rate of reaction is inversely proportional to the activation energy required. Which of the following expressions gives the effect of temperature on the reaction rate?

Answer»

In K= In A`-E_(a)//RT`
In k= In A`+E_(a)//RT`
In k = `A-E_(a)//RT)`
k= In A`+ "In" E_(a)//RT`

Solution :a) is the CORRECT ANSWER.
Discussion
86026.

According to the collision theory, only the effective collisions among the reacting species result in the products. In order that the collisions may be effective, the reacting species must have energy equal to or more than a certain minimum energy called threshold energy (E^(@)). Extra energy which has be supplied to the reactants to make collisions effective is known as activation energy (E_(a)). This is related to reaction rate with the help of Arrhenius equation, k=Ae^(-Ea//RT) The equation also helps in calculating the activation energy for a reaction at a specific temperature. In general, the rate of reaction is inversely proportional to the activation energy required. An increase in reaction rate with rise in temperature is due to

Answer»

an increase in the number of collisons
an increase in the number of activated molecules.
LOWERING the activation energy
shortening of MEAN FREE path.

Solution :B) is the correct ANSWER.
Discussion
86027.

According to the collision theory, only the effective collisions among the reacting species result in the products. In order that the collisions may be effective, the reacting species must have energy equal to or more than a certain minimum energy called threshold energy (E^(@)). Extra energy which has be supplied to the reactants to make collisions effective is known as activation energy (E_(a)). This is related to reaction rate with the help of Arrhenius equation, k=Ae^(-Ea//RT) The equation also helps in calculating the activation energy for a reaction at a specific temperature. In general, the rate of reaction is inversely proportional to the activation energy required. The plot of log k Vs 1//T helps to calculate

Answer»

ENERGY of activation
Rate CONSTANT of the reaction
Order of reaction
Energy of activation as WELL as the frequency FACTOR,

Solution :d) both energy of activation and frequency factor can be calcualted.
Discussion
86028.

According to the collision theory of chemical reactions,

Answer»

A chemical reaction occurs with every MOLECULAR collision
Rate is DIRECTLY proportional to the number of collisions PER second
Reactions in the gas phase are ALWAYS of ZERO order
Rates of reaction are of the order of molecular speeds

Answer :B
Discussion
86029.

According to the Arrhenius equation a straight line is. to be obtained by plotting the logarithm of the rate constant of a chemical reaction (log k) against:

Answer»

T
LOG T
`1//T`
`log 1//T`

ANSWER :C
Discussion
86030.

According to the Arrhenius equation a straight line is to be obtained by plotting the logarithm of the rate constant of a chemical reaction (log k) against

Answer»

LOG 1//T
T
`1//T`
log T

Answer :C
Discussion
86031.

According to the Arrhenius equation

Answer»

A high activation energy usually implies a fast reaction
Rate constant INCREASES with increase in temperature . This is due to a greater NUMBER of collisions whose energy exceeds the activation energy
Higher the magnitude of activation energy , stronger is the temperature DEPENDENCE of the rate constant
The pre-exponential factor is a measure of the rate at which collisions OCCUR , irrespective of their energy

Answer :bcd
Discussion
86032.

According to the Arrhenius equation,

Answer»

a HIGH ACTIVATION energy usually implies a fast reaction.
rate constant increases with increases in temperature. This is due to a greater NUMBER of collisions whose energy exceeds the activation energy.
higher the magnitude of activation energy, strongest is the temperature dependencies of the rate constant.
the pre-exponential factor is a measure of the rate at which collisions occur, irrespective of their energy.

Solution :(b,c,d) OPTIONS (b,c,d) are correct. Option (a) is WRONG because high activation energy usually implies a slow reaction.
Discussion
86033.

According to the adsorption theory of catalysis, the speed of the reaction increases because:

Answer»

In the PROCESS of adsorption, the CONCENTRATION of the molecules DECREASES at the surface of catalyst
Adsorption produces heat which increases the speed of the reaction
Adsorption lowers the ACTIVATION energy of the reaction
Adsorption increases the activation energy of the reaction

Answer :C
Discussion
86034.

According tothe adsorption theory of catalysis , the speed of the reaction increases because

Answer»

Adsorption produces heat which increases the speed of the reaction
Adsorption lowers the ACTIVATION energy of the reaction
The concentration of reactant molecules at the active centres of the catalyst becomes high due to adsorption
In the process of adsorption , the activation energy of the molecules become large

SOLUTION :A catalyst lowers the activation energy of the reaction FOLLOWING adsorption mechanism .
`because` RATE of reaction `prop (1)/("Activation energy")`
Discussion
86035.

According to the adsorption theory of catalysis the speed of the reaction increases because

Answer»

Adsorption produces HEAT which increses the speed of the reaction
Addsorption lowers the activation energy of the reaction
The CONCENTRATION of rectant molecules at the active centres of the catalyst BECOMES HIGH due to adsorption
In the process of adsorption the activation energy of the molecules BECOME large

Answer :B
Discussion
86036.

According to the adsorption theory of catalysis, the speed of the reaction increase because

Answer»

in the process of adsorption, the activation energy of the molecules becomes large
adsorption PRODUCES heat which increase the speed of the reaction.
adsorption lowers the activation energy of the reaction
the CONCENTRATION of product molecules at the active CENTRES of the catalyst becomes HIGH due to adsorption.

Solution :Adsorption lowers the activation energy.
Discussion
86037.

According to Slater.s rule, the set of elements that show incorrect order of Z_("eff") are :-

Answer»

`Al GT MG`
`Na lt Al`
`K gt Na`
`Sc LTTI`

Answer :C
Discussion
86038.

According to Slater's rule , correct order of Z_("eff") on valence shell electron is :

Answer»

`Fe gt Fe^(2+) gt Fe^(3+)`
`N^(3-) lt O^(2-) lt F^(-)`
`NA^(+) lt Mg^(2+) lt Al^(3+)`
`Tl^(2+) lt V^(3+) lt Mn^(5+)`

Solution :(B) `N^(3-) lt O^(2-) lt F^(-) [Z_(EFF)prop(1)/("Charge on anion")]`
(c) `Na^(+) Mt^(+) lt Al^(3+)`
(d) `Tl^(2+) lt V^(3+) lt Mn^(5+)`
Discussion
86039.

According to second law of thermodynamics, a process (reaction) is spontaneous, if during the process

Answer»

`DeltaS_("universe")GT0`
`DeltaS_("universe")=0`
`DeltaH_("system")=0`
`DeltaS_("universe")=DeltaS_("system")`

Solution :When a spontaneous (naturallyh occuring) process TAKES place, it is ACCOMPANIED by INCREASE in entropy, i.e.,
`DeltaS_("universe")=DeltaS_("system")+DeltaS_("surroundings")gt0`.
Discussion
86040.

According to Raoult's law the relative lowering of vapour pressure of a solution of non-volatile substance is equal to

Answer»

<P>Mole FRACTION of the solvent
Mole fraction of the solute
Weight PERCENTAGE of a solute
Weight percentage of solvent

Solution :`(p^(@)-p)/(p^(@))=((w)/(m))/((w)/(m)+(W)/(M))` = mole fraction of solute.
Discussion
86041.

According to Raoult's law, the relative loweringin vapour pressure of a solution is equal to :

Answer»

NUMBER of MOLES of solute
Number of moles of solvent
Mole FRACTION of solute
Mole fraction of solvent.

Answer :C
Discussion
86042.

According to Raoult's law, for which system of solution, the vapour pressure of both i.e., solute and solvent will be proportional to their mole fraction ?

Answer»

Both are VOLATILE
SOLUTE is volatile, SOLVENT is non volatile
Both are monvolatile
Solute is nonvolatile, solvent is volatile

Answer :A
Discussion
86043.

According to phase rule, if P = 3, C = 1, then F must be equal to

Answer»

1
4
2
Zero

Answer :D
Discussion
86044.

According to pauling the orbitals involved in the hybridisation to form a complex are

Answer»

Orbitals FILLED with TWO electrons each
Orbitals filled with ONE ELECTRON each
Orbitals not filled with electrons
Orbitals filled with one or two electrons

Answer :C
Discussion
86045.

According to Nernst theory , potential developed at an electrode is due to :

Answer»

ELECTRONATION only
De-electronation only
Electronation and de-electronation
Combustion

Solution :NERNST FORMULA.
Discussion
86046.

According to MOT, two atomic orbitals overlap resulting in the formation of molecular orbital formed. Number of atomic orbitals overlapping together is equal to the molecule orbital formed. Thetwo atomic orbital thus formed by LCAO (linear combination of atomic orbital)in the phase or in the different phase are known as bonding and antibonding molecular orbitals respectively. The energy of bonding molecular orbital is lower than that of the pure atomic orbitals by an amount Delta. This known as the stabilization energy. The enerby of antibonding molecular orbital in increased by Delta' (destabilisation energy). Q. If x-axis is the molecular axis, then pi-moleulcar orbitals are formed by the overlap of :

Answer»

<P>`S+p_(X)`
`p_(x) +p_(y)`
`P_(Z) +p_(x)`
`p_(x)+p_(x)`

SOLUTION :
Discussion
86047.

According to molecular orbital theory, which of the lists ranks the nitrogen species in terms of increasing bond order ?

Answer»

`N_(2)^(2-)LT N_(2)^(-)lt N_(2)`
`N_(2)lt N_(2)^(2-)lt N_(2)^(-)`
`N_(2)^(-)lt N_(2)^(2-)lt N_(2)`
`N_(2)^(-)lt N_(2)lt N_(2)^(2-)`

ANSWER :A
Discussion
86048.

According to molecular orbital theory, which of the following statement about the magnetic character and bond order is correct regarding O_(2)^(+)?

Answer»

PARAMAGNETIC and BOND ORDER `ltO_(2)`
Paramagnetic and bond order `gtO_(2)`
Diamagnetic and bond order `ltO_(2)`
Diamagnetic and bond order `gtO_(2)`

Answer :B
Discussion
86049.

According to modern periodic law, the physical and chemical properties of the elements are periodic function of their:

Answer»

ATOMIC number
atomic weight
atomic size
atomic volume.

Answer :A
Discussion
86050.

According to molecular collision theory,the reaction is subjected to……

Answer»

Number of molecular collision of reactant
Number of collision between reactant and ACTIVATED comolex
The collision RATE between reactant and PRODUCT molecules
Number of effective molecular collision of reactants

Answer :D
Discussion