Tag: patterns and properties of metals

Questions Related to patterns and properties of metals

In thermite welding, aluminium acts as a/an:

aluminium patterns and properties of metals chemistry

  1. solder

  2. flux

  3. oxidising agent

  4. reducing agent

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Correct Option: D
Explanation:

In thermite welding, aluminium acts as reducing agent. Aluminium is used in thermite welding of broken iron parts. The reduction of ferric oxide by aluminium is highly exothermic and therefore, the iron formed will be in the molten state. Thermite reaction involving aluminium is also called Goldschmidt alumino thermic reaction.

Read the following statements and choose the correct alternative.
Statement I :  Aluminium fool cannot bebe used in $\alpha $-particle - particle scattering experiment.
Statement II : Aluminium is a highly malleable metal.

aluminium patterns and properties of metals chemistry

  1. Both statement are true and statement II is a correct reason of Statement I.

  2. Both statement are true and statement II is a not correct reason of Statement I.

  3. Statement I is true and statement II is false

  4. Statement II is true and statement I is false

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Correct Option: C
Explanation:
  • If Aluminium foil was used the,the scattering angles would have changed, but the qualitative results would also change: the reason Rutherford chose gold was because it is EXTREMELY malleable. One can stretch gold foil until it is only a few atoms thick in places, which is not possible with aluminum.
  • Hence option C is correct answer.

${ aAl } _{ 2 }{ \left( { C } _{ 2 }{ O } _{ 4 } \right)  } _{ 3 }(s)\xrightarrow [  ]{ \Delta  } \quad { bAl } _{ 2 }{ O } _{ 3 }(s)+cCO(g)+d{ CO } _{ 2 }(g)$
According to the equation for the reaction represented above, what is the mole of $CO$ to ${CO} _{2}$ that is produced by the decomposition of aluminium oxalate?

aluminium patterns and properties of metals chemistry

  1. $1$ mole $CO$; $1$ mole of ${CO} _{2}$

  2. $1$ mole $CO$; $2$ moles of ${CO} _{2}$

  3. $1$ mole $CO$; $3$ moles of ${CO} _{2}$

  4. $2$ moles $CO$; $1$ mole of ${CO} _{2}$

  5. $3$ moles $CO$; $1$ mole of ${CO} _{2}$

Show answer
Correct Option: A
Explanation:

${ Al } _{ 2 }{ ({ C } _{ 2 }{ O } _{ 4 }) } _{ 3 }(s)\xrightarrow { \Delta  } { Al } _{ 2 }{ O } _{ 3 }(s)+3CO(g)+3C{ O } _{ 2 }(g)$

According to the equation for the reaction represented above, what is the mole of $CO$ to $C{ O } _{ 2 }$ that is produced by the decomposition of aluminium oxalate is 1 mole of $C{ O }$ : 1 mole of $C{ O } _{ 2 }$

X$ _2$O$ _3$ is produced if ratio of element to oxygen is 2:3 in the reaction of element and oxygen,what is that element?

aluminium patterns and properties of metals chemistry

  1. Ca

  2. Li

  3. Al

  4. F

  5. C

Show answer
Correct Option: C
Explanation:

$\displaystyle   X _2O _3$ is produced if ratio of element to oxygen is 2:3 in the reaction of element and oxygen, that element is Aluminum (Al). It forms $\displaystyle   Al _2O _3$ . The valence of Al (and X)  is +3 and that of oxygen is -2.
Ca, Li, F and C have valencies +2, +1, -1 and 4 respectively.

The dissolution of $Al(OH) _3$ by a solution of NaOH results in the formation of:

aluminium patterns and properties of metals chemistry

  1. $[Al(H _2O) _2(OH) _4]^-$

  2. $[Al(H _2O) _3(OH) _3]^+$

  3. $[Al(H _2O) _4(OH) _2]^+$

  4. $[Al(H _2O) _6(OH) _3]^-$

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Correct Option: A
Explanation:

1. $[Al(H _2O) _4(OH) _2]^+$

2. $Al(OH) _3$  dissolves in $NaOH$ solution to give $Al(OH)^{-4}$ ion which is supposed to have the octahedral complex species $[Al(OH) _4(H _2O) _2]^-$ in aqueous solution.

3. $Al(OH) _3 + NaOH(aq) \longrightarrow  [Al(OH) _4(H _2O) _2]^-(aq) + NaOH^+(aq)$

Aluminium chloride exists as dimer, $Al _{2}Cl _{6}$ in solid state as well as in solution of non-polar solvents such as benzene. When dissolved in water, it gives:

aluminium patterns and properties of metals chemistry

  1. $[Al(OH) _{6}]^{3-} + 3HCl$

  2. $Al _{2}O _{3} + 6HCl$

  3. $Al^{3+} + 3Cl^{-}$

  4. $[Al(H _{2}O) _{6}]^{3+} + 3Cl^{-}$

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Correct Option: D
Explanation:

When ${ Al } _{ 2 }{ Cl } _{ 6 }$ is dissolved in water, it is ionized to form ${ \left[ Al{ \left( { H } _{ 2 }O \right)  } _{ 6 } \right]  }^{ 3+ }$ and ${ Cl }^{ \left( - \right)  }$ due to large hydration energy of ${ Al }^{ 3+ }$.

${ Al } _{ 2 }{ Cl } _{ 6 }+12{ H } _{ 2 }O\rightleftharpoons 2{ \left[ Al{ \left( { H } _{ 2 }O \right)  } _{ 6 } \right]  }^{ 3+ }+{ 6Cl }^{ \left( - \right)  }$

Which of the following is soluble in water?

aluminium patterns and properties of metals chemistry

  1. $Na _2CO _3$

  2. $CaCO _3$

  3. $ZnCO _3$

  4. $Al _2(CO _3) _3$

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Correct Option: A

Hydrogen gas will not be produced by :

aluminium patterns and properties of metals chemistry

  1. heated cupric oxide

  2. heated Ferric oxide

  3. heated stannic oxide

  4. heated aluminium oxide

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Correct Option: D
Explanation:

When alluminium oxide is heted it liberates oxygen gas
$2Al _2O _3\rightarrow 4Al+3O _2$
So alluminium oxide on heating do not produce hydrogen gas
Hence option D is correct.

$AlCl _3$ is an electron deficient compound but $AlF _3$ is not. This is because:

aluminium patterns and properties of metals chemistry

  1. atomic size of F is smaller than Cl which makes $AlF _3$ more covalent

  2. $AlCl _3$ is a covalent compound while $AlF _3$ is an ionic compound

  3. $AlCl _3$ exists as a dimer but $AlF _3$ does not

  4. $Al$ in $AlCl _3$ is in $sp^3$ hybrid state but Al in $AlF _3$ is in $sp^2$ state

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Correct Option: B
Explanation:

There is this rule called as Fajan's rule which states that with increasing size of the anion and with decreasing size of the cation ionic character of the compound decreases while the covalent character increases.

Here, since the cation is same in both the compounds, the size of the anion decides the nature of the compound. Size of chlorine being greater than fluorine, $AlCl _3$ is covalent while $AlF _3$ is ionic.

All of the following are true for aluminum except that:

aluminium patterns and properties of metals chemistry

  1. it is a good conductor of electricity

  2. it is a metal of high density

  3. it forms a protective coating in air that resists further corrosion

  4. it is an excellent reducing agent

  5. it forms a hydroxide that that is soluble in both strong base and acid

Show answer
Correct Option: B
Explanation:

The properties of aluminium include low density and therefore low weight, high strength, superior malleability, easy machining, excellent corrosion resistance and good thermal and electrical conductivity.
The surface of aluminum metal is covered with a thin layer of oxide that helps protect the metal from attack by air. So, normally, aluminum metal does not react with air. Aluminium hydroxide is amphoteric in nature. Hence, it dissolves in both acidic and basic solution.