IMPORTANT SELECTED MODEL QUESTION FOR NEET, Chemistry neet exam model question paper, neet exam question paper, neet model paper, neet mode...
IMPORTANT
SELECTED MODEL QUESTION FOR NEET,Chemistry neet exam model question paper, neet exam question paper, neet model paper, neet model test, neet mcq
Q2Ans(d) Is known as fuel cell.
Q3Ans (a) (ii) and (iv) are correct realations
Q4Ans (b) Obtained product is Oxygen.
Q5. Ans (d) Q6.D
Q7.Ans (a) strong electrolytes are completely ionized at all concentrations. On increasing dilution the no. of ions remains same but the ionic mobility and equivalent conduction increases.
Q10. Ans (a) Enzymes act like catalyst in biochemical reactions. Presence of an enzyme increases the rate of reaction by lowering the activation energy of the reactant.
Q11.Ans (d) A catalyst affects equally for both forward and backward reactions. So it does not affect equilibrium constant of reaction.
Q12.d
Q13. Ans (d) Rate = k[A]2[B]3
Q14.a Q15.a Q16.c
Q17.Ans (b) Condensation method is used for destruction.
Q18.Ans (c) Adopt the ability of variable oxidation energy.
Q19.Ans (a) Fog is colloidal solution of liquid in gas.
Q20.d
Q21. Ans.(a) Langmuir adsorption isotherm is based on the assumption that every adsorption site is equivalent and whether sites are not occupied or occupied the ability of a particle to bind is independent.
Q22.d
Q23. Ans(d)Magnetitie (Fe2O3) is a mineral of iron.
Q24.d
Q25. Ans (c) Hypo is used in photography to remove under composed silver Bromide as soluble complex.
Q26.Ans (a) Magnesium and manganese are the metals that produce hydrogen with dilute nitric acid because they are electropositive in nature
Q27Ans (b) d-orbitals are available for bonding is not correct for nitrogen.
Q28.b
Q29. Ans (c) Strongest hydrogen bonding is shown by Hydrogen Fluoride
Q30. Ans (c) As halogens have seven electrons (ns2np2) in the valence shell, they have a strong tendency to acquire the nearest inert gas configuration by gaining an electron from the metallic atom and form halide ions easily.
Q31. (a) Hydrogen iodide has the liberate bromine.
Q32. Ans (a) NF5 does not exist because the size of nitrogen atom is very small
Q33. Ans (b) Brown ring test is used to detect nitrate.
Q34.d Q35.c
Q36 Ans (a) Ozone can only combine with hydrogen atoms.
Q37.d Q38.d Q39.a
Q40. Ans (b) CIF3 molecules all bond are not equal.
Q41.Ans (d) F2 is strongest oxidizing agent.
Q42. Ans (b) Order of acidic strength in strong acid are HCIO4 > H2SO4 > HCIO3 >H2SO3
Q43. Ans (a) SF4 is a polar molecule.
Q44. Ans (b) PCl3 +3H2O-----H3PO3+ 3HCl
Q45. Ans (a) phosphorus pentoxide has great affinity for water. It forms ortho phosphoric acid on absorbing water.
Q46. Ans (c) H3PO2 is named as hypophosphorus acid. As it contains only one P ---OH group, so its basicity is one
Q47. Ans (a) Due to absence of reaction between marble and bromine
Q48. Ans (b)Fluorine is more reactive than chlorine. So bond energy of chlorine is greater than fluorine.
Q49.b
Q50. Ans (c) By use of the joule-Thomson effect air is liquefied (cooling by expansion of the gas). Water vapour and CO2 are removed by solidification. The remaing constituents of liquid air (liquid oxygen and liquid nitrogen ) are seprated by means of fractional distillation (b.p of O2 = - 1830C :b.p of N2= -195.80C)
Q51.a
Q52.c
Q53. Ans (b) Acidic strength increases as the oxidation number of central atom increases
Q54. Ans (d) Ionic radii of trivalent lanthanides steadily increases with increase in atomic number
Q55.Ans (c)A layer of oxide is formed on the surface of nickel, which protects nickel, below it and iron underneath it.
Q56.Ans (d) Oxidation states shown by elements are as follows:
Q57. Ans (a) Interstitial compounds are obtained when small atoms like H,B,C,N etc. fit into the interstitial space of lattice metals. These retain metallic conductivity. These resemble the parent metal in chemical properties like hardness, Ans (b)Minimum energy gap between 5f, 6d and 7s subshell. That’s why e- excitation will be easier.melting point etc.
Q58. Ans (b)Minimum energy gap between 5f, 6d and 7s subshell. That’s why e- excitation will be easier.
Q59.Ans (b) As a result lanthanide contraction, the atomic radii of element of 4d and 5d come closer, so the properties of 4d and 5d transition element shows the similarities. The regular decrease in the radii of lanthanide ions from La3+ to Lu3+ is known as lanthanides contraction.
Q60. Ans (d
Q61. Ans (c) The 5f –orbitals extend into space beyond the 6s and 6p-orbitals and participate in bonding. This is in direct contrast to the lanthanides where the 4f-orbitals are buried
Q62 Ans (c) A transition element must have incomplete d-subshell. Zinc have completely filled d-subshell having 3d10 configuration . so do not show properties of transition elements to any appreciable extent except for their ability to form complexes.
Q63.b
Q64.a
Q65.(b)
Q66.(a)
Q67(b)
Q68 Ans (a) Primary alcohol undergoes catalytic dehydrogenation to give aldehyde.
Q69. Ans (c) Formation of a yellow precipitate on heating a compound with an alkaline solution of iodine is known as “iodoform reaction”.
Q70Ans Ans (d) Dihydrogen sodium phosphate (NaH2PO4) does not have a lone pair of electrons on the P-atom. As such it can not act as a nucleophile and does not react with aldehydes and ketones.
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Q1.On heating one end of a piece of a metal, the other end becomes hot because of
a)Resistance of the
metal
b)Mobility of atoms
in the metal
c)Energized
electrons moving to the other end
d)Minor perturbation
in the energy of atoms
Q2. A device that converts energy of combustion of the fuels like hydrogen and methane, directly into electrical energy is known as
(a)Electrolytic
cell(b)Dynamo
(c)Ni-Cd cell (d)
Fuel cell
Q3. Consider the following relations for emf of aelectrochemical cell
(i) Emf of cell =(Oxidation potential
of anode) –
(Reduction potential of cathode)
(ii) Emf of cell = (Oxidation potential
of anode)
+(Reduction potential of cathode)
(iii)emf of cell = (Reduction potential
of
anode)+(Reduction potential of cathode)
(iv) emf of cell = (Oxidation potential
of anode) –
(Oxidation potential of cathode)
Which of the above relation are
correct?
(a) (ii) and (iv)
(b) (iii) and (i)
(c)(i) and (ii)
(d) (iii) and (iv)
Q4.
On electrolysis of dilute sulphuric acid using platinum electrodes, the product
obtained at the anode will be
(a) Hydrogen
(b) Oxygen
(c)Hydrogen sulphide
(D)Sulphur dioxide
Q5.
During the electrolysis of molten sodium chloride, the time required to produce
0.10
mol of chlorine gas using a current of 3 amperes is
a)220 minumtes(b)330
monutes
(c)55 minutes(d) 110
minutes
Q6.
An electric current is passed through silver nitrate solution using silvern electrodes.
10.79 g of silver was found to be deposited on the cathode if the same amount
of sulphate solution using copper electrodes, the weight of copper deposited
onthe cathode is
(a)6.4g (b) 2.3 g
(c)12.8 g (d) 3.2g
Q7.
An increase in equilvalent conductance of a
strong
electrolyte with dilution is mainly due to:
(a) Increase in
ionic mobility of ions
(b) 100 % ionization
of electrolyte at normal
dilution
(c) Increase in both
i.e. number of ions and ionic
mobility of ions
(d) Increase in
number of ions
Q8.
The ionic conductance of Ba2+ and Cl- are respectively 127
and 76 ohm-1 cm2 at infinite dilution. The equivalent conductance (in ohm-1
cm2) of BaCl2 at infinite dilution will be :
(a)139.5 (b) 203
(c)279 (d) 101.5
Q9.
At 250C molar conductance of 0.1 molar aqueous solution of ammonium
hydroxide is 9.54 ohm-1 cm2 mol-1 and at
infinite dilution its molar conductance is 238 ohm-1 cm2 mol-1
.The degree or ionization of ammonium hydroxide at the same concentration an
temperature is
(a) 20.800% (b)
4.008%
(c)40.800% (d)
2.080%
Q10.How
enzymes increases the rate of reactions
(a) By lowering
activation energy
(b) By increasing
activation energy
(c) By changing
equilibrium constant
(d) By forming
enzyme substrate complex
Q11
. A chemical reaction is catalyzed by a catalyst X.Hence X
(a) Reduces enthalpy
of the reaction
(b) Decreases rate
constant of the reaction
(c) Increases
activation energy of the reaction
(d) Does not affect equilibrium
constant of the
reaction
Q12.
In a reaction, A +B -Ã Product,
rate is doubled when the concentration of B is
doubled,
and rate increases by a factor of 8 when the concentration of both the reactants
(A and B) are doubled, rate law for the reaction can be written as:
(a) Rate = K [A]
[B]2
(b) Rate = k[A]2[B]2
(c)Rate =k [A]2[B]2
(d) Rate =k[A]2[B]
Q13.
For a reaction between A and B the order with respect to A is 2 and the order
with respect to B is 3. The concentrations of both A and B are doubled, the
rate will increase by a factor of
(a) 10 (b) 12
(c)16 (d) 32
Q14.
The rate of a first order reaction is 0.04 mol-1s-1 at 10
seconds and 0.03 mol-1 s-1 of 20 seconds after initiation
of the reaction. The half-life period of the reaction is
(a) 24.1 s (b) 34.1s
(c)44.1s (d) 54.1s
Q15.
A first order reaction has a specific reaction rate of 10-2 sec-1.
How much time will it take for 20g of the reactant to reduce to 5g ?
(a) 138.6 sec(b)
346.5sec
(c)693.0sec (d)
238.6 sec
Q16.
When a few typical solutes are separated by a particular selective memberane
such as protein particles, blood corpuscles, this process is called
(a) Transpiration (b) Endosmosis
(c)Dialysis (d) Diffusion
Q17.
Which one of the following method is commonly used method for destruction of
colloid?
(a) Dialysis
(b)Condensation
(c)Filteration by
animal membrane
(d) By adding
electrolyte
Q18.The
catalytic activity of transitions metals and their compounds is describe mainly
due to
(a) Their magnetic
behavior
(b) Their unfilled
d-orbitals
(c)Their ability to
adopt variable oxidation states
(d) Their chemical
reactivity
Q19. Fog
is colloidal solution of
(a) Liquid in gas
(b) Gas is liquid
(c) Solid in gas
(d) Gas in gas
Q20. For
adsorption of a gas on a solid, the plot of log x/m versus log P is linear with
slope equal to (n being whole number )
(a) K (b) log k
(c)n (d) 1/n
Q21.
The Langmuir adsorption isotherm is deduced using the assumption
(a) The adsorption
sites are equivalent in their ability to adsorb the particles
(b) The heat of
adsorption varies with coverage
(c) The adsorbed
molecules interact with each other
(d) The adsorption
takes place in multilayers
Q22.
Method used for obtaining highly pure silicon used as a semiconductor material,
is
(a)Oxidation
(b)Electrochemical
(c)Crystallization
(d) Zone refining
Q23.
Which one of the following is a mineral of
iron
?
(a) Malachite (b)
Cassiterite
(b) Pyrolusite (d)
Magnetite
Q24.
Roasting of sulphides gives the gas X as a
byproduct.
This is a colourless gas with choking
smell
of brunt sulphur and causes great damage to respiratory organs as a result of
acid rain. Its
aqueous
solution is acidic, acts as a reducing agent and its acid has never been isolated.
The
gas X is
(a) CO2 (b) SO3
(c)H2S (d) SO2
Q25. Hypo
is used in photography to
(a) Reduce AgBr
grains to metallic silver
(b) Convert metallic
silver to salt
(c) Remove
undercomposed silver bromide as a soluble complex
(d) Remove reduced
silver
Q26.
Which of the following metal evolves hydrogen on reacting with cold dilute
HNO3?
(a)Mg (b) AI
(c)Fe (d) Cu
Q27. Which
of the following statement is not correct for nitrogen?
(a) Its
electronegativity is very high
(b) D-orbitals are
available for bonding
(c) It is typical
non-metal
(d) Its molecular
size is small
Q28.
Basicity of ortho phosphoric acid is
(a) 2 (b) 3
(c)4 (d) 5
Q29. Strongest
hydrogen bonding is shown by
(a) Water (b)
ammonia
(c)hydrogen fluoride
(d) hydrogen sulphide.
Q30.Elements
of which of the following groups will form anions most readily?
(a) Oxygen family
(b) Nitrogen family
(c)Halogens
(d) Alkali metals
Q31. A
solution of potassium bromide is treated with each of the following. Which
onewould liberate bromine?
(a) Hydrogen iodide
(b) Sulphur dioxide
(c)Chlorine
(d) Iodine
Q32. Which
of the following
fluorides
does not exist?
(a) NF5
(b) PF5
(c)AsF5
(d) SbF5.
Q33.
Brown ring test is used to detect
(a) Iodine (b)
Nitrate
(c)Iron (d) Bromide
Q34.
The acid which has a peroxy linkage is
(a) Sulphuric acid
(b) Pyrosulphuric
acid
(c) Dithionic acid
(d) Caro’s acid
Q35.
Repeated use of which one of the following
fertilizers
would increase the acidity of the soil?
(a) Urea
(b) Superphosphate
of lime
(c)Ammonium sulphate
(d) potassium
nitrate
Q36. During
its reactions, ozone
(a) Can only combine
with hydrogen atoms
(b) Accepts
electrons
(c) Loses electrons
(d) Shows the role
of electrons to be irrelevant
Q37.which
one of the following statement is not
true?
(a) Among halide
ions, iodide is the most powerful reducing agent
(b) Fluoride is the
only halogen that does not show a variable oxidation state.
c) HOCl is a
stronger acid than HOBr.
(d) HF is a stronger
acid than HCI
Q38. Which
one of the following is responsible for depletion of the ozone layer in the
upper strata of the atmosphere?
(a)Polyhalogens(b)Ferrocene
(c)Fullerenes (d)
Freons
Q39. Among
K, Ca, Fe and Zn, the element which can form more than one binary compound with
chlorine is
(a) Fe (b) Zn
(c)K (d) Ca
Q40. In
which of the following molecules are all
the
bonds are not equal?
(a) NF3
(b) CIF3
(c)BF3
(d) AIF3
Q41. Among
the followingwhich is the strongest
oxidizing
agent?
(a) Br2
(b) I2
(c)Cl2
(d) F2
Q42. Which
is the strongest acid in the following?
(a) HClO3
(b) HClO4
(c)H2SO3
(d) H2SO4
Q43.
Which of the following is a polar molecule?
(a) SF4
(b) SiF4
(c)XeF4
(d) BF3
Q44.
PCl3 is reacts with water to form
(a) PH3
(b) H3PO3,HCl
(c)POCl3
(d) H3PO4
Q45.Which
one of the following substance is used in the laboratory for fast drying of
neutral gases?
(a) Phosphorus
pentoxide
(b) Active charcoal
(c)Anhydrous calcium
chloride
(d) Na3PO4
Q46. H3PO2
is the molecular formula of an acid of phosphorus. Its name and basicity resepectively
are
(a)Phosphorus acid and two (b)Hypophosphorus acid
and two
(c)Hypophosphorous
acid and one
(d)Hypophosphoric
acid and two
Q47.A
one litre flask is full of brown bromine vapour. The intensity of brown colour
of vapour will not decrease appreciably on adding will not decrease appreciably
on adding to the flask some
(a) Pieces of marble
(b) animal charcoal
powder
(c)carbon tetrachloride
(d) carbon
disulphide
Q48. Which
of the following statement is true?
(a) Silicon exhibits
4 coordination number in its
compound.
(b) Bond energy of
F2 is less than Cl2
(c) Mn(III)
oxidation state is more stable than Mn(II) in aqueous state.
(d) Elements of 15th
group shows only + 3 and +5 oxidation states.
Q49.Which
is the correct statement for the given acids?
(a)Phosphinic acid
is a diprotic acid while
phosphonic acid is a
monoprotic acid
(b)Phosphinic acid
is a monoprotic acid while
phosphonic acid is a
diprotic acid
(c)Both are
triprotic acids
(d)Both are diprotic
acids
Q50. It
is possible to obtain oxygen from air by fractional distillation because
(a)Oxygen is in a
different group of the periodic table from nitrogen
(b)Oxygen is more
reactive than nitrogen
(c)Oxygen has higher
b.p than nitrogen
(d)Oxygen has a
lower density than nitrogen.
Q51.Oxidation
of thiosulphate by iodide gives.
(a)Tetrahionate ion
(b)Sulphide ion
(c)Sulphate ion
(d)Sulphite ion
Q52. Which
of the following does not give oxygen on heating?
(a)Zn(CIO3)2
(b)K2Cr2O7
(C)(NH4)2Cr2O7
(d) KCIO3
Q53.
Among the following the correct order of acidity is
(a)HCIO3 < HCIO4
<HCIO2 <HCIO
(b)HCIO < HCIO2
<HCIO3 <HCIO4
(c)HCIO2 <HCIO
<HCIO3 <HCIO4
(d)HCIO4 <HCIO2
<HCIO <HCIO2
Q54. Which
of the following statement concerning lanthanide elements is false?
(a)All lanthanides
are highly dense metals
(b)More
characteristic oxidation state of lanthanide elements is +3
(c)Lanthanides are
separated from one another by ion exchange method
(d)Ionic radii of
trivalent lanthanides steadily increase with increase in the atomic number.
Q55.
To protect iron against corrosion, the most durable metal plating on it, is
(a)Copper plating
(b)Zinc plating
(c)Nickel plating
(d)Tin plating
Q56.which
one of the following elements shows
maximum
number of different oxidation states in its compounds?
(a)Eu (b) La
(c)Gd (d) Am
Q57.Which
of the following statement about the
interstitial
compounds is incorrect?
(a)They are
chemically reactive.
(b)They are much
harder then the pure metal.
(c)They have higher
melting points than the pure metal.
d)They retain
metallic conductivity.
Q58.The
reason for greater range of oxidation states in actinoids is attributed to:
(a)Actinoid
contraction
(b)5f,6d
and 7s levels having comparable energies
(c)4f and 5d levels
being close in energies
(d)The radioactive
nature of actinoids
Q59.Identify
the following statement among the following
(a)Lanthanoid
contraction is the accumulation of
successive
shrinkages.
(b)As a result of
lanthanoid contraction, the properties of 4d series of the transition elements
have no similarties with the 5d series of elements.
(c)Shielding power
of 4f electrons is quite weak.
(d)There is a
decrease in the radii of the atoms or ions as one proceeds from La to Lu.
Q60.
Which one of the following statements is
correct
when SO2 is passed through acidified K2Cr2O7
solution?
(a)The solution
turns blue
(b)The solution is decolourized
(c)SO2 is reduced
(d)Green Cr2(SO4)3
is formed
Q61.
More number of oxidation states are exhibited by the actinoids than by the
lanthanoids.
The main reason for this is
(a)More active
nature of the actinoids
(b)More energy
difference between 5f and 6d orbitals than that between 4f and 5d orbitals
(c)Lesser energy
difference between 5f and 6d orbitals than that between 4f and 5d orbitals
(d)Greater metallic
character of the lanthanoids than that of the corresponding actinoids
Q62.Sc (Z=21) is
a transition element but Zn (Z=30) is not because
(a)Both Sc and Zn do
not exhibit variable oxidation states
(b)Both Sc3+
and Zn2+ ions are colourless and form white compounds
(c)In case of Sc, 3d
orbitals are partially filled but in Zn these are completely filled
(d)Last electron is
assumed to be added to 4s level in case of Zn
Q63. Industrial
preparation of chloroform employs acetone and
(a)Phosgene
(b) Calcium
hypochlorite
(c)Chlorine gas
(d) Sodium chloride
Q64.
An organic compound A(C4H9Cl) on reaction with Na/diethyl ether gives a
hydrocarbon
which on monichlorination gives only one chloro derivative, then A is
(a)Tert –butyl
chlorine
(b) sec-butyl
chloride
(c)isobutyl chloride
(d) n-butyl chloridE
Q65.
Which of the following is correct?
(a)Cycloheptane is
an
aromatic compound
(b)Diastase is an
enzyme
(c)Acetophenone is
an ether
(d)All of the above
Q67. Number
of isomeric alcohols of molecular formula C6H10O which give positive
iodoform test is
(a)Three (b) four
(c)five (d) two
Q68. What
is formed when a primary alcohol undergoes catalytic dehydrogenation?
(a) Aldehyde (b)
Ketone
(c)Alkene (d) Acid
Q69. Ethanol
and dimethyl ether form a part of
functional
isomers. The boiling point of ethanol is higher than that of dimethyl ether,
due to the presence of
(a)H- bonding in
ethanol
(b)H- bonding in
dimethyl ether
(c)CH3
group in ethanol
(d)CH3
group in dimethyl ether
Q70.Aldehydes
and ketones will not form crystalline derivatives with
(a)Sodium bisulphate
(b)phenylhydrazine
(c)semicarbazide hydrochloride
(d) Dihydrogen
sodium phosphate.
Answer
Q1Ans (c) Because of energized electrons moving to the other end
Q2Ans(d) Is known as fuel cell.
Q3Ans (a) (ii) and (iv) are correct realations
Q4Ans (b) Obtained product is Oxygen.
Q5. Ans (d) Q6.D
Q7.Ans (a) strong electrolytes are completely ionized at all concentrations. On increasing dilution the no. of ions remains same but the ionic mobility and equivalent conduction increases.
Q10. Ans (a) Enzymes act like catalyst in biochemical reactions. Presence of an enzyme increases the rate of reaction by lowering the activation energy of the reactant.
Q11.Ans (d) A catalyst affects equally for both forward and backward reactions. So it does not affect equilibrium constant of reaction.
Q12.d
Q13. Ans (d) Rate = k[A]2[B]3
When concentrations of both A and B are doubled then
Rate =k[2A]2[2B]3=32k [A]2[B]3[22 x23=32]
So, rate will increase by a factor of 32.
Q14.a Q15.a Q16.c
Q17.Ans (b) Condensation method is used for destruction.
Q18.Ans (c) Adopt the ability of variable oxidation energy.
Q19.Ans (a) Fog is colloidal solution of liquid in gas.
Q20.d
Q21. Ans.(a) Langmuir adsorption isotherm is based on the assumption that every adsorption site is equivalent and whether sites are not occupied or occupied the ability of a particle to bind is independent.
Q22.d
Q23. Ans(d)Magnetitie (Fe2O3) is a mineral of iron.
Q24.d
Q25. Ans (c) Hypo is used in photography to remove under composed silver Bromide as soluble complex.
Q26.Ans (a) Magnesium and manganese are the metals that produce hydrogen with dilute nitric acid because they are electropositive in nature
Mg +2HNO3------ Mg(NO3)2 +H2
Q27Ans (b) d-orbitals are available for bonding is not correct for nitrogen.
Q28.b
Q29. Ans (c) Strongest hydrogen bonding is shown by Hydrogen Fluoride
Q30. Ans (c) As halogens have seven electrons (ns2np2) in the valence shell, they have a strong tendency to acquire the nearest inert gas configuration by gaining an electron from the metallic atom and form halide ions easily.
Q31. (a) Hydrogen iodide has the liberate bromine.
Q32. Ans (a) NF5 does not exist because the size of nitrogen atom is very small
Q33. Ans (b) Brown ring test is used to detect nitrate.
Q34.d Q35.c
Q36 Ans (a) Ozone can only combine with hydrogen atoms.
Q37.d Q38.d Q39.a
Q40. Ans (b) CIF3 molecules all bond are not equal.
Q41.Ans (d) F2 is strongest oxidizing agent.
Q42. Ans (b) Order of acidic strength in strong acid are HCIO4 > H2SO4 > HCIO3 >H2SO3
Q43. Ans (a) SF4 is a polar molecule.
Q44. Ans (b) PCl3 +3H2O-----H3PO3+ 3HCl
Q45. Ans (a) phosphorus pentoxide has great affinity for water. It forms ortho phosphoric acid on absorbing water.
P4O10 +6H2O------- 4H3PO4
It is used as a powerful dehydrating or drying agent.
Q46. Ans (c) H3PO2 is named as hypophosphorus acid. As it contains only one P ---OH group, so its basicity is one
Q47. Ans (a) Due to absence of reaction between marble and bromine
Q48. Ans (b)Fluorine is more reactive than chlorine. So bond energy of chlorine is greater than fluorine.
Q49.b
Q50. Ans (c) By use of the joule-Thomson effect air is liquefied (cooling by expansion of the gas). Water vapour and CO2 are removed by solidification. The remaing constituents of liquid air (liquid oxygen and liquid nitrogen ) are seprated by means of fractional distillation (b.p of O2 = - 1830C :b.p of N2= -195.80C)
Q51.a
Q52.c
Q53. Ans (b) Acidic strength increases as the oxidation number of central atom increases
Q54. Ans (d) Ionic radii of trivalent lanthanides steadily increases with increase in atomic number
Q55.Ans (c)A layer of oxide is formed on the surface of nickel, which protects nickel, below it and iron underneath it.
Q56.Ans (d) Oxidation states shown by elements are as follows:
La = +3
Eu and Gd = +2 and +3
Am = +2 +3 +4 +5 and +6
Due to its longer size and low ionization energy am shows maximum
number of different ixidation state.
Q57. Ans (a) Interstitial compounds are obtained when small atoms like H,B,C,N etc. fit into the interstitial space of lattice metals. These retain metallic conductivity. These resemble the parent metal in chemical properties like hardness, Ans (b)Minimum energy gap between 5f, 6d and 7s subshell. That’s why e- excitation will be easier.melting point etc.
Q58. Ans (b)Minimum energy gap between 5f, 6d and 7s subshell. That’s why e- excitation will be easier.
Q59.Ans (b) As a result lanthanide contraction, the atomic radii of element of 4d and 5d come closer, so the properties of 4d and 5d transition element shows the similarities. The regular decrease in the radii of lanthanide ions from La3+ to Lu3+ is known as lanthanides contraction.
It is due to greater effect of the increased nuclear charge than
that of screening effect (shielding effect).
Q60. Ans (d
Q61. Ans (c) The 5f –orbitals extend into space beyond the 6s and 6p-orbitals and participate in bonding. This is in direct contrast to the lanthanides where the 4f-orbitals are buried
deep inside in the atom, totally shielded by outer orbitals and
thus unable to take part in bonding.
Q62 Ans (c) A transition element must have incomplete d-subshell. Zinc have completely filled d-subshell having 3d10 configuration . so do not show properties of transition elements to any appreciable extent except for their ability to form complexes.
Q63.b
Q64.a
Q65.(b)
Q66.(a)
Q67(b)
Q68 Ans (a) Primary alcohol undergoes catalytic dehydrogenation to give aldehyde.
Q69. Ans (c) Formation of a yellow precipitate on heating a compound with an alkaline solution of iodine is known as “iodoform reaction”.
alcohols which posses CH3CH(OH)--- group.
As: C2H3OH +4l2 +NaOH------CHl3+ Nal + HCOONa +H2O
Methyl alcohol does not respond to this test. Idoform test is
exhibited by ethyl alcohol, acetaldehyde, acetone, methyl ketones and those
Q70Ans Ans (d) Dihydrogen sodium phosphate (NaH2PO4) does not have a lone pair of electrons on the P-atom. As such it can not act as a nucleophile and does not react with aldehydes and ketones.
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