Transition and Inner Transition Elements - Tamil Nadu Board STD 12 Chemistry Questions

Q 1Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

Which of the following statements is not true?

A
on passing $\mathrm{H}_2 \mathrm{S}$, through acidified $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution, a milky colour is observed.
✓
$\mathrm{Na}_2 \mathrm{Cr}_2 \mathrm{O}_7$ is preferred over $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ in volumetric analysis
C
$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution in acidic medium is orange in colour
D
$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution becomes yellow on increasing the $\mathrm{P}^{\mathrm{H}}$ beyond 7

Answer: B.

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Q 2Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

In acid medium, potassium permanganate oxidizes oxalic acid to ____________.

A
oxalate
✓
Carbon dioxide
C
acetate
D
acetic acid

Answer: B.

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Q 3Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

The correct order of increasing oxidizing power in the series

✓
$VO _2^{+}< Cr _2 O _7^{2-}< MnO _4^{-}$
B
$Cr _2 O _7^{2-}< VO _2^{+}< MnO _4^{-}$
C
$Cr _2 O _7^{2-}< MnO _4^{-}< VO _2^{+}$
D
$MnO _4^{-}< Cr _2 O _7^{2-}< VO _2^{+}$

Answer: A.

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Q 4Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

The catalytic behaviour of transition metals and their compounds is ascribed mainly due to ____________.

A
their magnetic behaviour
B
their unfilled d orbitals
✓
their ability to adopt variable oxidation states
D
their chemical reactivity

Answer: C.

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Q 5Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

The magnetic moment of $Mn ^{2+}$ ion is____________.

✓
5.92 BM
B
2.80 BM
C
8.95 BM
D
3.90 BM

Answer: A.

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Q 6Fill In The Blanks.1 Mark

All the actinoids are …………. and most of them have …………. half lives.

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Q 7Fill In The Blanks.1 Mark

Due to the decrease in the size of $Ln ^{3+}$ ions, the ionic character of $Ln - OH$ bond decreases which results in the………….

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Q 8Fill In The Blanks.1 Mark

The common oxidation state of lanthanoids is ………….

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Q 9Fill In The Blanks.1 Mark

The equivalent weight of KMnO4 in neutral medium is ………….

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Q 10Fill In The Blanks.1 Mark

Baeyer’s reagent is used for detecting …………. in an organic compounds.

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Q 11Assertion And Reason.1 Mark

Assertion (A) – Transition metals form large number of complexes.
Reason (R) – Transition metals are small and highly charged and they have vacant low energy orbitals to accept an electron pair donated by other groups.

✓
Both (A) and (R) are correct and (R) is the correct explanation of (A)
B
Both (A) and (R) are correct but (R) is not the correct explanation of (A)
C
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is wrong

Answer: A.

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Q 12Assertion And Reason.1 Mark

Assertion (A) – Copper is unique in 3d series having a stable +1 oxidation state.
Reason (R) – Copper is prone to disproportionate to the +2 and 0 oxidation states.

A
Both (A) and (R) are correct but (R) is not the correct explanation of (A).
✓
Both (A) and (R) are correct and (R) explains (A).
C
(A) is correct but (R) is wrong.
D
(A) is wrong but (R) is correct.

Answer: B.

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Q 13Assertion And Reason.1 Mark

Assertion (A) $- Mn ^{2+}$ is more stable than $Mn ^{4+}$
Reason $(R)- Mn ^{2+}\left(3 d^5\right)$ is more stable than $Mn ^{4+}\left(3 d^3\right)$ is due to extra stability of half-filled electronic configuration.

✓
Both (A) and (R) are correct and (R) is the correct explanation of (A)
B
Both (A) and (R) are correct but (R) is not the correct explanation of (A)
C
(A) is correct but (R) is wrong
D
(A) is wrong but (R) is correct

Answer: A.

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Q 14Assertion And Reason.1 Mark

Assertion (A) – Except Scandium all 3d series, transition elements exhibit variable oxidation states.
Reason (R) – By loosing electrons from (n – l)d orbital and ns orbital as the energy difference between them is very small.

✓
Both (A) and (R) are correct and (R) explains (A).
B
Both (A) and (R) are correct but (R) is not the correct explanation of (A).
C
(A) is correct but (R) is wrong.
D
(A) is wrong but (R) is correct.

Answer: A.

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Q 15Assertion And Reason.1 Mark

Assertion (A) – Ni (II) compounds are thermodynamically more stable than Pt (II) compounds.
Reason (R) – The energy required to form $Ni^{2-}$ is less than that of $Pt ^{2+}$