Tag: structure of some compounds

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Questions Related to structure of some compounds

Multiple choice chemistry p- block elements-i study of aluminium chloride study of aluminium structure of some compounds

Some properties of aluminium are listed.
1 It has mechanical strength.
2 It is resistant to corrosion.
3 It has a low density.
4 It conducts heat.
Which three properties make aluminium useful for making the bodies of aircraft?

  1. $1, 2$ and $3$
  2. $1, 2$ and $4$
  3. $1, 3$ and $4$
  4. $2, 3$ and $4$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Solution:- (A) $1, \; 2$ and $3$

Aluminium is useful in making of aircraft bodies due to its mechanical strength, low density and corrosion resistance.

Multiple choice chemistry p- block elements-i study of aluminium chloride study of aluminium structure of some compounds

Anhydrous $AlCl _{3}$ is formed in:

  1. $AlCl _{3}.6H _{2}O \xrightarrow[]{\Delta}$
  2. $Al(red hot) + HCl(moist)\xrightarrow[]{\Delta}$
  3. $Al _{2}O _{3} + C+ Cl _{2}(dry) \xrightarrow[]{\Delta}$

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Anhydrous aluminium chloride cannot be obtained by heating its hydrated form because hydrolysis yields alumina and hydrochloric acid instead. It is industrially prepared by passing dry chlorine gas over a heated mixture of alumina and carbon.

Multiple choice chemistry p- block elements-i study of aluminium chloride study of aluminium structure of some compounds

On the hydrolysis of $Al{Cl} _{3}$ then the no. of ${Al}^{+3}$ will be:

  1. Is equal to chloride ions
  2. Is equal to $\cfrac{1}{3}$ chloride ions
  3. Three times of ${Cl}^{-}$ ion

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The hydrolysis reaction will be $AlC{ l } _{ 3 }+{ 3H } _{ 2 }O\rightarrow Al(OH{ ) } _{ 3 }+3HCl$

So the number of $A{ l }^{ +3 }$ will be equal to $\frac { 1 }{ 3 } $ chloride ions.

Multiple choice chemistry p- block elements-i study of aluminium chloride study of aluminium structure of some compounds

Anhydrous $Al{Cl} _{3}$ cannot be obtained from which of the following reactions :

  1. Heating $Al{Cl} _{3}.6{H} _{2}O$
  2. By passing dry $HCl$ over hot aluminium powder
  3. By passing dry ${Cl} _{2}$ over hot aluminium powder
  4. By passing dry ${Cl} _{2}$ over hot mixture of alumina and coke
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

On heating $AlCl _{ 3 }.6{ H } _{ 2 }O$ hydrolysis takes place to produce $Al\left( OH \right) _{ 3 }$ and $HCl$
and on further heating $Al\left( OH \right) _{ 3 }$ converts to $Al _{ 2 }O _{ 3 }$.

By passing dry $HCl$ or ${ Cl } _{ 2 }$ over heated aluminium,
$2Al+3C{ l } _{ 2 }\longrightarrow 2AlC{ l } _{ 3 }$

$2Al+6HC{ l }\longrightarrow 2AlC{ l } _{ 3 }+3{ H } _{ 2 }$

Macah's method:$Al _{ 2 }O _{ 3 }+3C+3{ Cl } _{ 2 }(dry)\xrightarrow [ \Delta  ]{  } 2AlC{ l } _{ 3 }+3CO\uparrow $

Multiple choice chemistry p- block elements-i study of aluminium chloride study of aluminium structure of some compounds

$AlF _{ 3 }$ is soluble in HF only in presence of KF. its is due to the formation of:

  1. $AlH _{ 3 }$
  2. $K\left[ AlF _{ 3 }H \right]$
  3. ${ K } _{ 3 }\left[ AlF _{ 3 }{ H } _{ 3 } \right]$
  4. ${ K } _{ 3 }\left[ AlF _{ 6 } \right]$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$AlF _3$ is insoluble in the anhydrous $HF$ because the $F$ ions are not available in intermolecular hydrogen bonded $HF$ but it becomes soluble in the  presence of $KF$ due to the formation of soluble complex,

$K _3[AlF _6]$
$AlF _3+3KF\longrightarrow K _3[AlF _6]$