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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 :
  • SiO2
  • CO2
  • SnO2
  • PbO2
The bond dissociation energy of BF in BF3 is 646 kJ mol1 whereas that of CF in CF4 is 515 kJ mol1. Comment on the above statement.
  • stronger σ bond between B and F in BF3 as compared to that between C and F in CF4
  • significant pπpπ interaction between B and F in BF3 whereas there is no possibility of such interaction between B and F in CF4
  • lower degree of pπpπ interaction between B and F in BF3 than that between C and F in CF4
  • smaller size of Batom as compared to that of Catom.
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(|Si|O)n
  • OO|Si|OO
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(OH4)] and the geometry of the complex are respectively:
  • sp3, tetrahedral
  • sp3, square planar
  • sp3d2, octahedral
  • dsp2, 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
  • GeCl2 is more stable than GeCl4
  • GeCl2 is acidic
  • GeCl4 in HCl forms [GeCl6]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 π bonds.
Reason : The heavier elements of p-block form dπdπ 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:
  • MeSiCl3
  • Me2SiCl2
  • Me3SiCl
  • Me4Si
Element M+N2ΔH2ONH3
Element M belonging to group 13 can be ?
  • B or Al
  • Ga or Al
  • B or Ga
  • In or TI
Ionisation enthalpy (ΔiH1 kJ mol1) 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 MF36?
  • B
  • Al
  • Ga
  • In
Which of the following is correct?
  • % abundance of B10=% abundance of B11
  • % abundance of B10>% abundance of B11
  • % abundance of B10<% abundance of B11
  • none of the above
Which among CH4,SiH4,GeH4,SnH4 is the most volatile?
  • CH4
  • SiH4
  • GeH4
  • SnH4
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 BOH presents in borax is ?
  • 3
  • 4
  • 5
  • 6
Which of the following statements is correct?
  • BCl3 and AlCl3 are both Lewis acids and BCl3 is stronger acid than AlCl3
  • BCl3 and AlCl3 both Lewis acids and AlCl3 is stronger acid than BCl3
  • BCl3 and AlCl3 are both equally strong Lewis acids
  • Both BCl3 and AlCl3 are not Lewis acids
Stability order of +3 and +1 states of boron family elements is:
  • Ga3+<In3+<Tl3+
  • Ga3+>In3+>Tl3+
  • Ga+<In+<Tl+
  • Ga3+<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?
  • CCl4 >SiCl4
  • SiCl4 >CCl4
  • SiCl4=CCl4
  • 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 511 elements
  • Group 59 elements
  • Group 79 elements
  • Group 911 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?
  • Pb4+>Pb2+>Pb
  • Pb>Pb2+>Pb4+
  • Pb2+>Pb>Pb4+
  • 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
CO2 is a gas, while SiO2 is a solid but both are:
  • covalent containing π -bond
  • molecules having pπ - dπ bonding
  • acidic
  • discrete molecules
In which of the following molecule back bonding is present?
  • BF3
  • H2O
  • NH3
  • HF
Boron exists in two isotopic form B10 and B11. If the average atomic weight of B is 10.20 u, select the correct statement.
  • % abundance of B10=% abundance of B11
  • % abundance of B10>% abundance of B11
  • % abundance of B10<% abundance of B11
  • % abundance of B10=% abundance of B112
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
  • H3BO3 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 H3BO3 GIVES IT A LAYERED STRUCTURE.
Teflon polymer is formed by the polymerisation of:
  • CH2CNCN
  • F2C=CF2
  • Cl2C=CH2
  • H2C=CHCl
Which of the following compounds of elements in group IV expected to be most ionic?
  • PbCl2
  • PbCl4
  • CCl4
  • SiCl4
Select the incorrect statement among the following:
  • BF3 and BCl3 both have equal bond angles
  • XeO2F2 has two pπpπ bonds
  • SF6 has all equal bond lengths
  • CH2Cl2 is less polar than CH3Cl
The element with lowest electronegativity in 13th group is:
  • B
  • Al
  • Ga
  • In
Aluminium does not react with:
  • NaOH
  • HCI
  • N2
  • HNO3
H2O2 is a:
  • monobasic acid
  • dibasic acid
  • neutral compound
  • weak alkali
Compound A is produced by absorbing dinitrogen trioxide in Na2CO3 solution. Compound A is:
  • Na2O
  • NaNO2
  • N2O
  • Na2N2O2
Which one of the following is the correct statement?
  • Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase
  • B2H6.2NH3 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  XeO3 molecule ?
  • sp
  • sp3
  • sp2
  • none
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