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

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2021 11 questions

Q852021 · 1 Sept 2021 · Shift 2· Numerical answer
If $80 g$ of copper sulphate $CuS O_{4} \cdot 5 H_{2} O$ is dissolved in deionised water to make $5 L$ of solution. The concentration of the copper sulphate solution is $x \times 1 0^{- 3} mol L^{- 1}$ . The value of x is ____. [Atomic masses $Cu : 63.54 u$ , $S : 32 u$ , $O : 16 u$ , $H : 1 u$ ]
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Answer: 64
Q872021 · 1 Sept 2021 · Shift 2· Numerical answer
The spin-only magnetic moment value of $B_{2}^{+}$ species is ____ $\times 1 0^{- 2} BM$ . (Nearest integer) [Given : $3 = 1.73$ ]
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Answer: 173
Q672021 · 25 Jul 2021 · Shift 2
The spin only magnetic moments (in BM) for free $T i^{3 +}$ , $V^{2 +}$ and $S c^{3 +}$ ions respectively are : (At.No. Sc : 21, Ti : 22, V : 23)
1. A.3.87, 1.73, 0
2. B.1.73, 3.87, 0
3. C.1.73, 0, 3.87
4. D.0, 3.87, 1.73
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Answer: B
Q712021 · 20 Jul 2021 · Shift 1
1. A.Both compound 'A' and compound 'B' are dicarboxylic acids
2. B.Both compound 'A' and compound 'B' are diols
3. C.Compound 'A' is diol and compound 'B' is dicarboxylic acid
4. D.Compound 'A' is dicarboxylic acid and compound 'B' is diol
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Answer: D
Q722021 · 18 Mar 2021 · Shift 1
1. A.
2. B.
3. C.
4. D.
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Answer: C
Q792021 · 18 Mar 2021 · Shift 2
Match List - I with List - II : $(a) (b) (c) (d) List - I Mercury Copper Silicon Nickel (i) (ii) (iii) (iv) List - II Vapour phase refining Distillation refining Electrolytic refining Zone refining$ Choose the most appropriate answer from the option given below :
1. A.(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
2. B.(a)-(ii), (b)-(iv), (c)-(iii), (d)-(i)
3. C.(a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)
4. D.(a)-(i), (b)-(iv), (c)-(ii), (d)-(iii)
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Answer: A
Q722021 · 16 Mar 2021 · Shift 1
Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R : Assertion A : Size of $B k^{3 +}$ ion is less than $N p^{3 +}$ ion. Reason R : The above is a consequence of the lanthanoid contraction. In the light of the above statements, choose the correct answer from the options given below :
1. A.Both A and B are true and R is the correct explanation of A
2. B.A is false but R is true
3. C.A is true but R is false
4. D.Both A and B are true but R is not the correct explanation of A
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Answer: C
Q672021 · 26 Feb 2021 · Shift 1
Which one of the following lanthanoids does not form $M O_{2}$ ? [M is lanthanoid metal]
1. A.Nd
2. B.Dy
3. C.Yb
4. D.Pr
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Answer: C
Q682021 · 26 Feb 2021 · Shift 1
1. A.
2. B.
3. C.
4. D.
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Answer: A
Q812021 · 25 Feb 2021 · Shift 2· Numerical answer
Copper reduces $N O_{3}^{-}$ into $NO$ and $N O_{2}$ depending upon the concentration of $HN O_{3}$ in solution. (Assuming fixed $[C u^{2 +}]$ and $P_{NO} = P_{N O_{2}}$ ), the $HN O_{3}$ concentration at which the thermodynamic tendency for reduction of $N O_{3}^{-}$ into $NO$ and $N O_{2}$ by copper is same is $1 0^{x} M$ . The value of 2x is ____. (Rounded off to the nearest integer) [Given, $E_{C u^{2 +} /Cu}^{o} = 0.34 V$ , $E_{N O_{3}^{-} /NO}^{o} = 0.96 V$ , $E_{N O_{3}^{-} /N O_{2}}^{o} = 0.79 V$ and at $298 K$ , $\frac{R T}{F} (2.303) = 0.059$ ]
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Answer: 4
Q822021 · 25 Feb 2021 · Shift 2· Numerical answer
The spin only magnetic moment of a divalent ion in aqueous solution (atomic number 29) is _________ BM (nearest integer).
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Answer: 2