Tag: d and f block elements

Questions Related to d and f block elements

Which of the following form an alloy?

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. $Zn+Pb$

  2. $Fe+Hg$

  3. $Pt+Hg$

  4. $Fe+C$

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Correct Option: D
Explanation:

Iron and Carbon form a significant number of alloys including Steel.


Hence option D is correct.

Which of the following set of metals can form alloy.

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. $Cu$ and $Au$

  2. $Li$ and $Na$

  3. $Fe$ and $Hg$

  4. All of the above

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Correct Option: A
Explanation:

Metals combined with other substances to make them stronger, harder, lighter, or better in some other way. An alloy like this will form only if the atoms of the base metal and those of the alloying agent are of roughly similar size. In most substitution alloys, the constituent elements are quite near one another in the periodic table. 

Corinthian bronze, is an alloy of copper with gold or silver.
Almost all metals can form amalgams with mercury, the notable exceptions being iron, platinum, tungsten, and tantalum.

Permanent magnets are generally made of alloys of.

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. Co

  2. Zn

  3. Mn

  4. Pb

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Correct Option: A

German silver alloy contains:

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. Zinc, silver and copper

  2. Nickel, silver and copper

  3. Germanium, silver and copper

  4. Zinc, nickel and copper

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Correct Option: D
Explanation:

German silver alloy contains $Cu\left( 25-30 \right)$%, $Zn\left( 25-35 \right)$% and $Ni\left( 10-35 \right) $%.

Which of the following metals are present in Devarda alloy?

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. $Cu$

  2. $Al$

  3. $Zn$

  4. $Ag$

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Correct Option: A,B,C
Explanation:

Devarda's alloy is  an alloy of aluminium (44% – 46%), copper (49% – 51%) and zinc (4% – 6%).

Devarda's alloy is used as reducing agent in analytical chemistry for the determination of nitrates after their reduction to ammonia under alkaline conditions.

Hence option A,B and C are correct.

Generally transition elements form coloured salts due to the presence of unpaired electrons. Which of the following compounds will be coloured in solid state? 

chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

  1. $Ag _2SO _4$

  2. $CuF _2$

  3. $ZnF _2$

  4. $Cu _2Cl _2$

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Correct Option: B
Explanation:
The respective transition elements exists in
$Ag^{+}-{4d}^{10}5s^0$, (have completely filled d orbital)
$Cu^{+2}-3d^{9}4s^0$, (have incompletely filled d orbital)
$Zn^{+2}-3d^{10}4s^0$ , (have completely filled d orbital)
$Cu^{+1}-3d^{10}4s^0$ (have completely filled d orbital),
Since, $Cu^{+2}$ has unpaired electron it will show electron transitions. 
Hence will be coloured.

In which of the following ions, the colour is not due to $d-d$ transition?

chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

  1. $[Ti(H _2O) _6]^{3+}$

  2. $[Cu(NH _3) _4]^{2+}$

  3. $[CoF _6]^{3-}$

  4. $CrO _4^{2-}$

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Correct Option: D
Explanation:
Colour is due to d-d transtition ,then such complexes have colour due to d-d transition are surely octahedral complexes.
Among the given options,                                                   
                                         ${ \left[ Ti{ \left( { H } _{ 2 }O \right)  } _{ 6 } \right]  }^{ 3+ }$
                                        ${ \left[ Cu{ \left( { NH } _{ 3 } \right)  } _{ 4 } \right]  }^{ 2+ }$
                                           ${ \left[ { COF } _{ 6 } \right]  }^{ 3- }$
This are octahedral complexes.
$CrO _4^{2-}$ is a salt,it colour is not due to d-d transition.

Match the column I with column II and mark the appropriate choice.

Column I Column II
(A) $FeSO _4.7H _2O$ (i) Green
(B) $NiCl _2.4H _2O$ (ii) Light Pink
(C) $MNCl _2.4H _2O$ (iii) Pale green
(D) $CoCl _2.6H _20$ (iv) Pink
(E) $Cu _2Cl _2$ (v) Colourless
chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

  1. (A) - (iii), (B) - (iv), (C) - (i), (D) - (ii), (E) - (v)

  2. (A) - (ii), (B) - (iii), (C) - (iv), (D) - (i), (E) - (v)

  3. (A) - (v), (B) - (ii), (C)-(iii), (D) - (iv), (E) - (i)

  4. (A) - (iii), (B)-(i), (C)-(ii), (D) - (iv), (E).- (v)

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Correct Option: D
Explanation:

The colour of the following compounds are:

(i) $FeSO _4$. & $H _2O$ - Pale green.
(II) $NiCl _2$.$4H _2O$ -Green
(iii) $MnCl _2$.$4H _2O$ - Light pink
(iv) $CoCl _2$.$6H _2O$ - Pink
(v) $CuCl _2$ - Colourless.
The colour of the transition metal compounds is due to partially filled d orbitals. Due to that,  d-d transition its complementary colour is seen. 
Hydrated complexes are coloured because in that come H$ _2$O molecules act as a ligand and gets arranged around the central metal atom so as to bring d-d transition.

For $Zn^{2+}$, $Ni^{2+}$, $Cu$, and $Cr^{2+}$ which of the following statements is correct?

chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

  1. Only $Zn^{2+}$ is colourless and $Ni^{2+}$, $Cu^{2+}$ and $Cr$ are coloured

  2. All the ions are coloured

  3. All the ions are colourless

  4. $Zn^{2+}$and $Cu^{2+}$ are colourless while $Ni^{2+}$ and $Cr^{2+}$ are coloured

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Correct Option: A
Explanation:

Since $Zn^{+2}$ have fully filled $d$ orbital having no unpaired electrons,it does not undergo electronic transitions,hence colourless.However,rest of the elements given as $Ni^{+2}$ , $Cu^{+2}$ and $Cr^{+2}$ has unpaired electrons which can undergo electronic transitions and hence show colours.

Which of the following group contains coloured ions?
1. $Cu^+$
2. $Ti^{4+} $
3. $Co^{2+}$
4.  $Fe^{2+}$

chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

  1. $1,4$

  2. $3,4$

  3. $2,3$

  4. $1,2$

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Correct Option: B
Explanation:

$Cu^{+}$ and $Ti^{+4}$ have fully filled and empty d orbital respectively. Hence due to absence of unpaired electrons,they will be colourless. But $Fe^{+2}$ and $Co^{+2}$chave unpaired electrons. Hence they will be coloured.