d- and f-Block Elements · JEE Main previous year questions

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2023 21 questions

Q812023 · 13 Apr 2023 · Shift 1· Numerical answer
$KMnO_{4}$ is titrated with ferrous ammonium sulphate hexahydrate in presence of dilute $H_{2} SO_{4}$ . Number of water molecules produced for 2 molecules of $KMnO_{4}$ is ___________.
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Answer: 68
Q872023 · 13 Apr 2023 · Shift 1· Numerical answer
A metal surface of $100 cm^{2}$ area has to be coated with nickel layer of thickness $0.001 mm$ . A current of $2 A$ was passed through a solution of $Ni (N O_{3})_{2}$ for 'x' seconds to coat the desired layer. The value of $x$ is ___________. (Nearest integer) ( $ρ_{Ni}$ (density of Nickel) is $10 g mL^{- 1}$ , Molar mass of Nickel is $60 g mol^{- 1}$ $F = 96500 C mol^{- 1}$ )
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Answer: 161
Q782023 · 11 Apr 2023 · Shift 1
In the extraction process of copper, the product obtained after carrying out the reactions (i) $2 C u_{2} S + 3 O_{2} \to 2 C u_{2} O + 2 S O_{2}$ (ii) $2 C u_{2} O + C u_{2} S \to 6 Cu + S O_{2}$ is called
1. A.Copper matte
2. B.Blister copper
3. C.Reduced copper
4. D.Copper scrap
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Answer: B
Q832023 · 11 Apr 2023 · Shift 1· Numerical answer
The ratio of spin-only magnetic moment values $μ_{eff} [Cr (CN)_{6}]^{3 -} / μ_{eff} [Cr (H_{2} O)_{6}]^{3 +}$ is _________.
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Answer: 1
Q642023 · 10 Apr 2023 · Shift 1
1. A.
2. B.
3. C.
4. D.
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Answer: A
Q662023 · 10 Apr 2023 · Shift 1
Which of the following statements are correct? (A) The $M^{3 +} / M^{2 +}$ reduction potential for iron is greater than manganese. (B) The higher oxidation states of first row d-block elements get stabilized by oxide ion. (C) Aqueous solution of $Cr^{2 +}$ can liberate hydrogen from dilute acid. (D) Magnetic moment of $V^{2 +}$ is observed between 4.4 - 5.2 BM. Choose the correct answer from the options given below :
1. A.(B), (C) only
2. B.(A), (B) only
3. C.(A), (B), (D) only
4. D.(C), (D) only
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Answer: A
Q832023 · 10 Apr 2023 · Shift 2· Numerical answer
For a metal ion, the calculated magnetic moment is 4.90 BM. This metal ion has _________ number of unpaired electrons.
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Answer: 4
Q842023 · 10 Apr 2023 · Shift 2· Numerical answer
In alkaline medium, the reduction of permanganate anion involves a gain of __________ electrons.
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Answer: 3
Q682023 · 8 Apr 2023 · Shift 1
In chromyl chloride, the number of d-electrons present on chromium is same as in (Given at no. of $Ti : 22, V : 23, Cr : 24, Mn : 25, Fe : 26$ )
1. A. $Mn (VII)$
2. B. $Ti (III)$
3. C. $Fe (III)$
4. D. $V (IV)$
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Answer: A
Q822023 · 8 Apr 2023 · Shift 2· Numerical answer
The observed magnetic moment of the complex $[Mn (\underline{N} CS)_{6}]^{x}$ is $6.06 BM$ . The numerical value of $x$ is ____.
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Answer: 4
Q612023 · 6 Apr 2023 · Shift 1
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: The spin only magnetic moment value for $[Fe (CN)_{6}]^{3 -}$ is $1.74 BM$ , whereas for $[Fe (H_{2} O)_{6}]^{3 +}$ is $5.92 BM$ . Reason R : In both complexes, Fe is present in +3 oxidation state. In the light of the above statements, choose the correct answer from the options given below:
1. A.Both A and R are true and R is the correct explanation of A
2. B.A is true but R is false
3. C.A is false but R is true
4. D.Both A and R are true but R is NOT the correct explanation of A
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Answer: D
Q692023 · 6 Apr 2023 · Shift 2
During the reaction of permanganate with thiosulphate, the change in oxidation of manganese occurs by value of 3. Identify which of the below medium will favour the reaction.
1. A.aqueous neutral
2. B.both aqueous acidic and faintly alkaline
3. C.both aqueous acidic and neutral
4. D.aqueous acidic
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Answer: A
Q812023 · 31 Jan 2023 · Shift 1· Numerical answer
Zinc reacts with hydrochloric acid to give hydrogen and zinc chloride. The volume of hydrogen gas produced at STP from the reaction of $11.5 g$ of zinc with excess $HCl$ is ___________ L (Nearest integer) (Given : Molar mass of Zn is $65.4 g mol^{- 1}$ and Molar volume of $H_{2}$ at $STP = 22.7 L$ )
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Answer: 4
Q632023 · 30 Jan 2023 · Shift 1
In the wet tests for identification of various cations by precipitation, which transition element cation doesn't belong to group IV in qualitative inorganic analysis?
1. A. $Co^{2 +}$
2. B. $Ni^{2 +}$
3. C. $Zn^{2 +}$
4. D. $Fe^{3 +}$
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Answer: D
Q862023 · 30 Jan 2023 · Shift 1· Numerical answer
A trisubstituted compound 'A', $C_{10} H_{12} O_{2}$ gives neutral $FeCl_{3}$ test positive. Treatment of compound 'A' with $NaOH$ and $CH_{3} Br$ gives $C_{11} H_{14} O_{2}$ , with hydroiodic acid gives methyl iodide and with hot conc. $NaOH$ gives a compound B, $C_{10} H_{12} O_{2}$ . Compound 'A' also decolorises alkaline $KMnO_{4}$ . The number of $π$ bond/s present in the compound 'A' is ___________.
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Answer: 4
Q872023 · 30 Jan 2023 · Shift 1· Numerical answer
The number of electrons involved in the reduction of permanganate to manganese dioxide in acidic medium is _____________.
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Answer: 3
Q752023 · 25 Jan 2023 · Shift 1
Which one of the following reactions does not occur during extraction of copper?
1. A. $2FeS + 3 O_{2} \to 2FeO + 2S O_{2}$
2. B. $FeO + Si O_{2} \to FeSi O_{3}$
3. C. $CaO + Si O_{2} \to CaSi O_{3}$
4. D. $2C u_{2} s + 3 O_{2} \to 2C u_{2} O + 2S O_{2}$
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Answer: C
Q872023 · 25 Jan 2023 · Shift 1· Numerical answer
How many of the following metal ions have similar value of spin only magnetic moment in gaseous state? ____ (Given : Atomic number V, 23; Cr, 24; Fe, 26; Ni, 28) $V^{3 +}, C r^{3 +}, F e^{2 +}, N i^{3 +}$
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Answer: 2
Q762023 · 25 Jan 2023 · Shift 2
Match List I with List II $A. B. C. D. List I Cobalt catalyst Syngas Nickel catalyst Brine solution I. II. III. IV. List II (H_{2} + C l_{2}) production Water gas production Coal gasification Methanol production$ Choose the correct answer from the options given below :
1. A.A-IV, B-III, C-I, D-II
2. B.A-IV, B-III, C-II, D-I
3. C.A-II, B-III, C-IV, D-I
4. D.A-IV, B-I, C-II, D-III
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Answer: B
Q612023 · 24 Jan 2023 · Shift 1
The primary and secondary valencies of cobalt respectively in $[Co (NH_{3})_{5} Cl] Cl_{2}$ are :
1. A.2 and 8
2. B.2 and 6
3. C.3 and 5
4. D.3 and 6
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Answer: D
Q682023 · 24 Jan 2023 · Shift 1
The magnetic moment of a transition metal compound has been calculated to be 3.87 B.M. The metal ion is
1. A. $T i^{2 +}$
2. B. $V^{2 +}$
3. C. $C r^{2 +}$
4. D. $M n^{2 +}$
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Answer: B