d- and f-Block Elements PYQs Set 5 (PDF)

Set 5 of 15 · Questions 121-150 of 443

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Mere Teacher · Previous Year Questions JEE Main Chemistry · d- and f-Block Elements · Set 5 (Q121-150)
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121. $Given below are some of the statements about Mn and Mn2O7. Identify the correct statements.(A) Mn forms the oxide Mn2O7, in which Mn is in its highest oxidation state.(B) Oxygen stabilizes the Mn in higher oxidation states by forming multiple bonds with Mn .(C) Mn2O7 is an ionic oxide.(D) The structure of Mn2O7 consists of one bridged oxygen. Choose the correct answer from the options given below :$ (1) $(A) (B) and (D) Only$ (2) $(A) (B) and (C) Only$ (3) $(A) (B) (C) and (D)$ (4) $(A) (C) and (D) Only$ 122. $Given below are two statements : Statement I: The first ionization enthalpy of Cr is lower than that of Mn . Statement II: The second and third ionization enthalpies of Cr are higher than those of Mn . In the light of the above statements, choose the correct answer from the options given below:$ (1) $Both Statement I and Statement II are true$ (2) $Both Statement I and Statement II are false$ (3) $Statement I is false but Statement II is true$ (4) $Statement I is true but Statement II is false$ 123. $Which of the following is an amphoteric oxide ?$ (1) $CrO3$ (2) $Cr2O3$ (3) $V2O3$ (4) $TiO$ 124. $For the four successive transion elements (Cr, Mn, Fe and Co), the stability of +2 oxidation state will be there in which of the following order ? (At. nos. Cr = 24, Mn = 25, Fe = 26, Co = 27)$ (1) $Mn > Fe > Cr > Co$ (2) $Fe > Mn > Co > Cr$ (3) $Co > Mn > Fe > Cr$ (4) $Cr > Mn > Co > Fe$ 125. $Assertion (A) : Transition elements have higher enthalpies of atomization. Reason (R) : Large number of unpaired electrons present in transition elements facilitate strong interatomic interaction and strong bonding between atoms.$ (1) $Both (A) and (R) are correct and (R) is the correct explanation of (A)$ (2) $Both (A) and (R) are correct and (R) is not the correct explanation of (A) .$ (3) $(A) Is correct and (R) is incorrect.$ (4) $(A) Is incorrect and (R) is correct.$ 126. $Identify the metal that forms colourless compounds.$ (1) $Iron (Z = 26)$ (2) $Chromium (Z = 24)$ (3) $Vanadium (Z = 23)$ (4) $Scandium (Z = 21)$ 127. $Most common oxidation state fo Ce (Cerium) are :$ (1) $+3, +4$ (2) $+2, +3$ (3) $+2, +4$ (4) $+3, +5$ 128. $The increase in the atomic radii of the third (5d) series of transition elements is very small, which may be accounted for the filling of ' X' orbitals before ' Y' orbitals. X and Y are X Y$ (1) $4f 5d$ (2) $5f 5d$ (3) $5d 4f$ (4) $4f 4d$ 129. $Which one of the elements with the following outer orbital configurations may exhibit the largest number of oxidation states?$ (1) $3 d^{5} 4 s^{1}$ (2) $3 d^{5} 4 s^{2}$ (3) $3 d^{2} 4 s^{2}$ (4) $3 d^{3} 4 s^{2}$ 130. $Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionization enthalpy ?$ (1) $Vanadium (Z = 23)$ (2) $Manganese (Z = 25)$ (3) $Chromium (Z = 24)$ (4) $Iron (Z = 26)$ 131. $The valence shell electronic configuration of Cr and Cu atoms, respectively, are$ (1) $3 d^{4} 4 s^{2}; 3 d^{10} 4 s^{1}$ (2) $3 d^{5} 4 s^{1}; 3 d^{10} 4 s^{1}$ (3) $3 d^{5} 4 s^{1}; 3 d^{9} 4 s^{2}$ (4) $3 d^{4} 4 s^{2}; 3 d^{9} 4 s^{2}$ 132. $The highest magnetic moment is shown by the transition metal ion with the configuration$ (1) $3 d^{2}$ (2) $3 d^{5}$ (3) $3 d^{7}$ (4) $3 d^{9}$ 133. $The number of ions from the following that have the ability to liberate hydrogen from a dilute acid is Ti^{2 +}, Cr^{2 +} and V^{2 +}$ (1) $2$ (2) $3$ (3) $1$ (4) $0$ 134. $Which of the following is not arranged in the correct sequence?$ (1) $MO, M_{2} O_{3}, M_{2}, M_{2} O_{5} (Decreasing basic nature)$ (2) $Sc, V, Cr, Mn (Increasing number of oxidation states)$ (3) $d^{5}, d^{3}, d^{1}, d^{4} (Increasing magnetic moment)$ (4) $Mn^{2 +}, Fe^{2 +}, Cr^{2 +}, Co^{2 +} (Decreasing stability)$ 135. $The electronic configuration of transition element X, is +3 , oxidation state is [Ar] 3 d^{5} . What is its atomic number?$ (1) $25$ (2) $26$ (3) $27$ (4) $24$ 136. $In which of the following pairs are both the ions coloured in aqueous solution?.(At. no. : S c = 21, T i = 22, N i = 28, C u = 29, C o = 27)$ (1) $N i^{2 +}, C u^{+}$ (2) $N i^{2 +}, T i^{3 +}$ (3) $S c^{3 +}, T i^{3 +}$ (4) $S c^{3 +}, C o^{2 +} .$ 137. $KMnO4 acts as an oxidising agent in the neutral medium and gets reduced to MnO2. The equivalent weight of KMnO4 in neutral medium will be :$ (1) $mol. wt. / 2$ (2) $mol. wt. / 3$ (3) $mol. wt. / 4$ (4) $mol. wt. / 7$ 138. $The atomic numbers of V, Cr, Mn and Fe are respectively 23, 24, 25 and 26. Which one of these may be expected to have the highest second ionization enthalpy ?$ (1) $Cr$ (2) $Mn$ (3) $Fe$ (4) $V$ 139. $The yellow colour of chromate ion and orange colour of dichromate ion is due to$ (1) $d - d transition only$ (2) $charge transfer only$ (3) $both d - d transition and charge transfer$ (4) $s - d transitions only$ 140. $In the standardization of N a_{2} S_{2} O_{3} using K_{2} C r_{2} O_{7} by iodometry, the equivalent weight of K_{2} C r_{2} O_{7} is$ (1) $(molecular weight)/2, (molar mass)/2$ (2) $(molecular weight)/6$ (3) $(molecular weight)/3$ (4) $same as molecular weight$ 141. $Which of the following combination will produce H_{2} gas ?$ (1) $Fe metal and conc. H N O_{3}$ (2) $Cu metal and conc. H N O_{3}$ (3) $Au metal and NaCN(aq) in the presence of air$ (4) $Zn metal and NaOH(aq)$ 142. $For the four successive transition elements (Cr, Mn, Fe and Co), the stability of + 2 oxidation state will be there in which of the following order$ (1) $M n > F e > C r > C o$ (2) $F e > M n > C o > C r$ (3) $C o > M n > F e > C r$ (4) $C r > M n > C o > F e (At. nos.$ 143. $Which of the following statement is not correct$ (1) $La (O H)_{3} is less basic than Lu (O H)_{3} .$ (2) $In lanthanide series ionic radius of L n^{+ 3} ion decreases.$ (3) $La is actually an element of transition series rather lanthanides.$ (4) $Atomic radius of Zn and Hf are same because oflanthanide contraction.$ 144. $Choose the correct statements from the following A. Mn_{2} O_{7} is an oil at room temperature B. V_{2} O_{4} reacts with acid to give VO_{2}^{2 +} C. CrO is a basic oxide D. V_{2} O_{5} does not react with acid Choose the correct answer from the options given below :$ (1) $A, B and D only$ (2) $A and C only$ (3) $A, B and C only$ (4) $B and C only$ 145. $How many protons will be consumed when dichromate ion oxidises Fe^{2 +} ions in aqueous acidic medium?$ (1) $4$ (2) $6$ (3) $10$ (4) $14$ 146. $The spin-only magnetic moment value of the ion among Ti^{2 +}, V^{2 +}, Co^{3 +} and Cr^{2 +}, that acts as strong oxidising agent in aqueous solution is_______BM (Near integer). (Given atomic numbers: Ti : 22, V : 23, Cr : 24, Co : 27)$ 147. $Manganese (VI) has ability to disproportionate in acidic solution. The difference in oxidation states of two ions it forms in acidic solution is______$ 148. $Number of moles of H^{+} ions required by 1 mole of MnO_{4}^{-} to oxidise oxalate ion to CO_{2} is_______$ 149. $The oxidation states of transition metal atoms in K_{2} C r_{2} O_{7}, KMn O_{4} and K_{2} Fe O_{4}, respectively, are x, y and z . The sum of x, y and z is :$ 150. $Consider the following reaction MnO_{2} + KOH + O_{2} \to A + H_{2} O . Product ' A' in neutral or acidic medium disproportionate to give products ' B' and ' C' along with water. The sum of spin-only magnetic moment values of B and C is BM . (nearest integer) (Given atomic number of Mn is 25)$