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CBSE Questions for Class 11 Engineering Chemistry Some P-Block Elements Quiz 9 - MCQExams.com

The shapes and hybridisation of BF3andBH4 respectively are:
  • BF3 - Trigonal, sp2 hybridisation ;

    BH4 - Square planar, sp3 hybridisation
  • BF3 - Triangular, sp3d hybridisation ;

    BH4 - Hexagonal, sp3d hybridisation
  • BF3 - Trigonal, sp2 hybridisation ;

    BH4 - Tetrahedral, sp3 hybridisation
  • BF3 - Tetrahedral, sp3 hybridisation;

    BH4 - Tetrahedral, sp3 hybridisation.
An oxide X in its normal form is almost non-reactive due to very high X - O bond enthalpy. It resists the attack by halogens, hydrogen and most of acids and metals even at elevated temperatures. It is only attacked by HF and NaOH. The oxide X is :
  • SiO_2
  • CO_2
  • SnO_2
  • PbO_2
The bond dissociation energy of B - F in BF_3 is 646 kJ mol^{-1} whereas that of C - F in CF_4 is 515 kJ mol{-1}. Comment on the above statement.
  • stronger \sigma bond between B and F in BF_3 as compared to that between C and F in CF_4
  • significant p\pi - p\pi interaction between B and F in BF_3 whereas there is no possibility of such interaction between B and F in CF_4
  • lower degree of p\pi -p\pi interaction between B and F in BF_3 than that between C and F in CF_4
  • smaller size of B-atom as compared to that of C-atom.
Topaz, opal, agate, and onyx are precious and beautiful stones found in nature. All these are different forms of:
  • silica
  • soda
  • carbon
  • lime
Which of the following is not matched correctly with its use?
  • piezoelectric material - Quartz
  • Ion-exchangers - Graphite
  • Filtration plants - silica
  • Electrical insulators - Silicones
Borax (sodium tetraborate) has many uses, some of which are mentioned here, except?
  • For giving a glaze to linen, in laundering
  • In bleaching of paper pulp
  • Making heat-resistant
  • As a flux in welding and soldering
Silica gel is a very useful:
  • raw material for soap
  • drying agent
  • wetting agent
  • solvent
Which of the following bonds is shown in silicones?
  • O-\!\!\!\!(\underset{|}{ \overset{|}Si}-O-\!\!\!\!)_n
  • O-\underset{O}{\underset{|}{\overset{O}{\overset{|}{Si}}}}-O
The geometry of a complex species can be understood from the knowledge of type of hybridisation of orbitals of central atom. The hybridisation of orbitals of central atom in [B(OH_4)]^- and the geometry of the complex are respectively:
  • sp^3, tetrahedral
  • sp^3, square planar
  • sp^3d^2, octahedral
  • dsp^2, square planar
Spaceships have to be air-tight because in space there is no air, only vaccum. Which of the following compounds has been used for air-tight closing of the door (hatch) in lunar modules?
  • Chlorides
  • Silicones
  • Bakelite
  • Hydrocarbons
Clay is used for making bricks and flower pots. If the clay article is not dried before 'firing' in a kiln, there will be evaporation of water from the surface and the :
  • kiln fire will be put out by steam
  • article will becomes soft
  • article will become hard
  • article will develop cracks
Elements of group 14 exhibit oxidation sate of:
  • +4 only
  • +2 and +4 only
  • +1 and +3 only
  • +2 only
Which is not correct?
  • GeO is acidic
  • Ge{ Cl }_{ 2 } is more stable than Ge{ Cl }_{ 4 }
  • Ge{ Cl }_{ 2 } is acidic
  • Ge{ Cl }_{ 4 } in HCl forms { \left[ Ge{ Cl }_{ 6 } \right] }^{ 2- } ion
Which of the following statements is correct with respect to the property of elements with increase in atomic number in the carbon family (group 14)?
  • Their metallic character decreases.
  • The stability of +2 oxidation state increases.
  • Their ionization energy increases.
  • Their atomic size decreases.
Assertion : The heavier p-block elements do not form strong \pi bonds.
Reason : The heavier elements of p-block form d\pi-d\pi bonds.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is not the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
Silicon has a strong tendency to form polymers like silicones. The chain length of silicone polymer can be controlled by adding:
  • MeSiCl_3
  • Me_2SiCl_2
  • Me_3SiCl
  • Me_4Si
Element M+{ N }_{ 2 }\xrightarrow [  ]{ \Delta  } \xrightarrow [  ]{ { H }_{ 2 }O } { NH }_{ 3 }
Element M belonging to group 13 can be ?
  • B or Al
  • Ga or Al
  • B or Ga
  • In or TI
Ionisation enthalpy (\Delta _iH_1\ kJ \ mol^{-1}) for the elements of Group 13 follows the order:
  • B > Al > Ga > In > Tl
  • B < Al > Ga < In > Tl
  • B < Al > Ga > In > Tl
  • B > Al < Ga > In < Tl
The exhibition of the highest co-ordination number depends on the availability of vacant orbitals in the central atom. Which of the following elements is not likely to act as a central atom in MF_6^{3-}?
  • B
  • Al
  • Ga
  • In
Which of the following is correct?
  • \% abundance of B^{10}=% abundance of B^{11}
  • \% abundance of B^{10}>% abundance of B^{11}
  • \% abundance of B^{10}<% abundance of B^{11}
  • none of the above
Which among { CH }_{ 4 }, { SiH }_{ 4 }, { GeH }_{ 4 }, { SnH }_{ 4 } is the most volatile?
  • { CH }_{ 4 }
  • { SiH }_{ 4 }
  • { GeH }_{ 4 }
  • { SnH }_{ 4 }
The element with atomic number 33 belongs to:
  • group 13
  • group 14
  • group 15
  • group 16
Borax, disodium tetraborate is an a important boron compound, a mineral, and a salt of boric acid. The number of terminal B-----OH presents in borax is ?
  • 3
  • 4
  • 5
  • 6
Which of the following statements is correct?
  • BCl_3 and AlCl_3 are both Lewis acids and BCl_3 is stronger acid than AlCl_3
  • BCl_3 and AlCl_3 both Lewis acids and AlCl_3 is stronger acid than BCl_3
  • BCl_3 and AlCl_3 are both equally strong Lewis acids
  • Both BCl_3 and AlCl_3 are not Lewis acids
Stability order of +3 and +1 states of boron family elements is:
  • { Ga }^{ 3+ }<{ In }^{ 3+ }<{ Tl }^{ 3+ }
  • { Ga }^{ 3+ }>{ In }^{ 3+ }{ >Tl }^{ 3+ }
  • { Ga }^{ + }<{ In }^{ + }<{ Tl }^{ + }
  • { Ga }^{ 3+ }<{ Ga }^{ + }
Which of the following statements is correct with respect to the property of elements with increase in atomic number in the carbon family (group 14)?
  • Their metallic character decreases.
  • The stability of +2 oxidation state increases.
  • Their ionization energy increases.
  • Their atomic size decreases.
Which of the following is correct order of boiling point?
  • {CCl}_{4}\ >{SiCl}_{4}
  • {SiCl}_{4}\ >{CCl}_{4}
  • {SiCl}_{4}={CCl}_{4}
  • None of these
Moissan boron is_____
  • Amorphous boron of ultra purity
  • Crystalline boron of ultra purity
  • Amorphous boron of low purity
  • Crystalline boron of low purity
Four hydrogenation reactions maximum catalytic activity is shown by:
  • Group 5-11 elements
  • Group 5-9 elements
  • Group 7-9 elements
  • Group 9-11 elements
Which of the following statement is incorrect?
  • The hydroxide of aluminium is more acidic than that of boron
  • The hydroxide of boron is basic whereas that of aluminium is amphoteric
  • The hydroxide of boron is acidic whereas that of aluminium is amphoteric
  • The hydroxide of both boron and aluminium are amphoteric
What the covalencey of phosphorus atoms in excited state?
  • 3
  • 4
  • 5
  • 1
Borax when dissolved in water exhibts
  • Alkaline nature
  • Acidic nature
  • Neutral nature
  • Amphoteric nature
Which of the following is correct w.r.t. to the radii related to lead?
  • Pb^{4+} > Pb^{2+} > Pb
  • Pb > Pb^{2+} > Pb^{4+}
  • Pb^{2+} > Pb > Pb^{4+}
  • Depends upon conditions
The relative stability of +1 oxidation state of group 13 elements follows the order:
  • Al < Ga < Tl < In
  • Tl < In < Ga < Al
  • Al < Ga < In < Tl
  • Ga < Al < In < Tl
CO_2 is a gas, while SiO_2 is a solid but both are:
  • covalent containing \pi -bond
  • molecules having p\pi - d\pi bonding
  • acidic
  • discrete molecules
In which of the following molecule back bonding is present?
  • BF_3
  • H_2 O
  • NH_3
  • HF
Boron exists in two isotopic form B^{10} and B^{11}. If the average atomic weight of B is 10.20\ u, select the correct statement.
  • \% abundance of B^{10}=\% abundance of B^{11}
  • \% abundance of B^{10} > \% abundance of B^{11}
  • \% abundance of B^{10} < \% abundance of B^{11}
  • \% abundance of B^{10}=\dfrac{\%\ abundance\ of\ B^{11}}{2}
The electropositive character is the maximum for which of the following elements in group 13?
  • Al
  • B
  • Ga
  • In
Boric acid is used in carom boads for smooth gliding of pawns because
  • H_3BO_3 molecules are loosely chemically bonded and hence soft
  • its low density makes it fluffy
  • it can be powdered to a very small grain size
  • it is chemically inert with the plywood
  • H-bonding in H_3BO_3 GIVES IT A LAYERED STRUCTURE.
Teflon polymer is formed by the polymerisation of:
  • CH_2CN-CN
  • F_2C=CF_2
  • Cl_2C=CH_2
  • H_2C=CHCl
Which of the following compounds of elements in group IV expected to be most ionic?
  • PbCl_{2}
  • PbCl_{4}
  • CCl_{4}
  • SiCl_{4}
Select the incorrect statement among the following:
  • {BF}_{3} and B{Cl}_{3} both have equal bond angles
  • Xe{O}_{2}{F}_{2} has two p\pi-p\pi bonds
  • {SF}_{6} has all equal bond lengths
  • {CH}_{2}{Cl}_{2} is less polar than {CH}_{3}Cl
The element with lowest electronegativity in 13th group is:
  • B
  • Al
  • Ga
  • In
Aluminium does not react with:
  • NaOH
  • HCI
  • N_2
  • HNO_3
H_{2}O_{2} is a:
  • monobasic acid
  • dibasic acid
  • neutral compound
  • weak alkali
Compound A is produced by absorbing dinitrogen trioxide in Na_{2}CO_{3} solution. Compound A is:
  • Na_{2}O
  • NaNO_{2}
  • N_{2}O
  • Na_{2}N_2O_{2}
Which one of the following is the correct statement?
  • Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase
  • {B_2}{H_6}.2N{H_3} is known as 'inorganic' benzene
  • Boric acid s a protoic acid
  • Beryllium exhibits coordinatin number of six
Which of the following metal is highest electropositive ( metallic) in nature?
  • Be
  • Rb
  • Mn
  • Mg
Which silicon compound is used in machinery (with moving parts) in a manner similar to the use of an allotrope of carbon (crystalline) which possesses properties of both a covalent network solid and a molecular solid?
  • Silica gel
  • Zeolite
  • Silicone
  • Asbestos
Hybridisation in of  Xe{O_3} molecule ?
  • s{p}
  • s{p^3}
  • s{p^2}
  • none
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