Chemistry - Some p-Block Elements

Question - 1

H3BO3 is

  • A monobasic and weak Lewis acid
  • B monobasic and weak Bronsted acid
  • C monobasic and strong Lewis acid
  • D tribasic and weak Bronsted acid

Question - 2

In III A group,TI(thallium,) shows +1 oxidation state while other members show +3 oxidation state,why?

  • A Presence of ione electron in TI
  • B Inert pair effect
  • C Large ionic radius of TI ion
  • D None of the above

Question - 3

The liquefield metal expanding on solidification is

  • A Ga
  • B Al
  • C Zn
  • D Cl

Question - 4

Ionisation enthalpy(\(\Delta \)iH1 kJ mol-1) for the elements of group 13 follows the order

  • A B > Al > Ga > In > Ti
  • B B < Al < Ga < In < Ti
  • C B > Al > Ga < In >Tl
  • D B > Al < Ga > In < Tl

Question - 5

The B-F bond length in BF3 is shorter than that in \(B{ F }_{ 4 }^{ - }\).This is because of

  • A resonance in BF3 but not in \(B{ F }_{ 4 }^{ - }\) 
  • B p\(\pi \)-p\(\pi \) back bonding in \(B{ F }_{ 4 }^{ - }\) but not in \(B{ F }_{ 3 }\)
  • C p\(\pi\)-p\(\pi\) back bonding in \(B{ F }_{ 3 }\) but not in \(B{ F }_{ 4 }^{ - }\)
  • D p\(\pi\)-d\(\pi\) back bonding in \(B{ F }_{ 3 }\) but not in \(B{ F }_{ 4 }^{ - }\)

Question - 6

Soldiers of Napolean army while at Alps during freezing winter suffered a serious problem as regards to the tin buttons of their uniforms. White metallic tin buttons got converted to grey powder.This transformation is related to  

  • A an interaction with nitrogen of the air at very low temperatures
  • B a change in the partial pressure of oxygen in the air
  • C a change in the crystalline structure of tin
  • D an interaction with water vapour contained in the humid air

Question - 7

The order of acidic strength of boron trihalides

  • A BF3 < BCI3 < BBr3 < BI3
  • B BI3 < BBr3 < BCI3 < BF3
  • C BCI3 < BBr3 < BI3 < BF3
  • D BBr3 < BCI3 < BF3 < BI3

Question - 8

Aluminium chloride exists as dimer Al2Cl6 in solid state as well as in solution of non-polar solvents such as benzone.When dissolved in water,it gives 

  • A [Al(OH)6]3- + 3HCl
  • B Al2O3 + 6HCl
  • C Al3+ + 3Cl-
  • D [Al(H2O)6]3+ + 3Cl-

Question - 9

Which of the following is known as inorganic benzene?

  • A Borazine
  • B Phosphonitrilic acid
  • C Boron nitride
  • D p-dichlorobenzene

Question - 10

The structure of diborane(B2H6) contains

  • A four 2c-2e- bonds and four 3c - 3e- bonds
  • B two 2c-2e- bonds and two 3c - 3e- bonds
  • C two 2c-2e- bonds and four 3c - 3e- bonds
  • D four 2c-2e- bonds and two 3c - 3e- bonds
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