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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 451. |
The first ionsation enthalpies of the lanthanoids are around…A….,the second about ….B…. Comparable with those of …..C….Here, A,B and C refers to `A. `A-600KJmol^(-1),B-1200KJmol^(-1)C-"calcium"`B. `A-1200KJmol^(-1),B-600KJmol^(-1)C-"strontium"`C. `A-1200KJmol^(-1),B-600KJmol^(-1)C-"lanthanum"`D. `A-600KJmol^(-1),B-1200KJmol^(-1)C-"lutetium"` |
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Answer» Correct Answer - A The first ionisation enthalpies of the lanthanoids are around `600KJ mol^(-1), the second about 1200KLmol^(-1)` comparable with those of calcium. |
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| 452. |
Among the following electronic configurations of d-orbitals, the electronic configuration showing the highest magnetic moment isA. `3d^(2)`B. `3d^(5)`C. `3d^(7)`D. `3d^(8)` |
| Answer» Correct Answer - B | |
| 453. |
Which of the following oxides of chromium is amphoteric in nature ?A. CrOB. `Cr_(2)O_(3)`C. `CrO_(3)`D. `CrO_(5)` |
| Answer» Correct Answer - b | |
| 454. |
Which is the last element in the series of the actinods? Write the electronic configuration of this element. Comment on the possible oxidation state of this element. |
| Answer» Lawrencium (Lr=103),`[Rn]5f^(14)6d^(1)7s^(2)`, oxidation state =+3 | |
| 455. |
Whys is chemistry of all lanthaoids identical ? |
| Answer» In the lanthanoid family, filling of electrons takes place (n-2) f-orbitals i.e., 4f orbitals whereas they actually below to sixth period (n=6). This means that these 4f electrons are shielded by the electrons present in the outer shells and ar normally not available for the bond formation. Therefore, chemistry of all lanthanoids ( similarly of actinoids )is identical. | |
| 456. |
The chemistry of the actionid elements is not so smooth as that of the lanthaoids. Justify this statements by giving some example from the oxidation state of these elements. |
| Answer» Lanthanoids show limited number of oxidation state, viz., `+2, +3, ` and `+4` ( out of which `+3` is most common.) This is because of large energy gap between 4f and 5 d subshells. The dominant oxidation state of actinoids is also `+3` but they show a number of ther oidation states also, e.g., uranium `(Z = 92)` and plutonium `( Z= 94)` , show `+ 3, + 4, + 5 ` and `+6` , nuptunium `(Z = 94)` shows `+ 3, +4 , +5` and `+7` etc. This is due to small energy difference between 5f , 6d and 7s subshells of the actinoids. | |
| 457. |
Which of the following statements concern with d-block metals?A. compounds containing ions of transition elements are usually colouredB. the most common oxidation state is `+3`C. `they show variable oxidation states, which differ by two units onlyD. they easily form complexes |
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Answer» Correct Answer - A::B::D `Mac^(-)` Arthur forest cyanideprons `M+CN^(-)+2H_(2)O+O_(2)to4[M)CN)_(2)]+4[O]` It is applicable for noble metals. |
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| 458. |
`E^(Theta)` value for the couple `Cr^(3+)//Cr^(2+)` and `Mn^(3+)//Mn^(2+)` are `-0.41 and +1.51` volts respectively. Considering these value select the correct option from the following statements.A. `Cr^(2+)` is a reducing and `Mn^(3+)` is an oxidising agentB. `Cr^(2+)` is more stable than `Cr^(3+)`C. `Mn^(3+)` is more stable than `Mn^(2+)`D. `Cr^(2+)` acts as on oxidising whereas `Mn^(3+)` acts as a reducing agent |
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Answer» Correct Answer - A `Cr^(3+)e^(-)toCr^(2+).E^(@)=-0.41` volts and `Mn^(3+)+e^(-) to Mn^(2+) E^(@)=+1.51` volts These values indicate that `Cr^(2+)` is unstable `(`negative reduction potential`)` and would like to axquire more stable `Cr^(3+)` state by acting as a reducing agent. `Mn^(3+)` is unstable and gets reduced to more stable `Mn^(2+)` form. |
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| 459. |
When ammonium dichloromate is heated it decompose and a spark is produced. The accompanying reaction is calledA. phosphorescenceB. incandescenceC. chemical valcanoD. fluorescence |
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Answer» Correct Answer - C When ammonium dichromate is heated, the following reaction takes place: `(NH_(4))_(2)Cr_(2)O_(7) overset(Delta)(to)Cr_(2)O_(3)+N_(2)+4H_(2)O` `Cr_(2)O_(3)` which is formed is blown out due to explosion on ignition. Hence, it is called chemical volcano. It is an exothermic reaction. |
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| 460. |
A mixture of `K_(2)Cr_(2)O_(7)` and conc. `H_(2)SO_(4)` formsA. perchromic acidB. chromic sulphateC. chromium oxideD. |
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Answer» Correct Answer - B When `K_(2)Cr_(2)O_(7)+2H_(2)SO_(4)to2CrO_(3)+2KHSO_(4)+H_(2)O` This mixture is called chromic acid because `CrO_(3)` is highly acidic. |
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| 461. |
Chromyl chloride tsts is used to detectA. `NO_(2)^(-)`B. `OH^(-)`C. `Cl^(-)`D. `Cn^(-)` |
| Answer» Correct Answer - C | |
| 462. |
What do you mean by (a) Chromyl Chloride test (b) Actinoids? |
| Answer» (b) Actinoids are the elements present in the f-block of the peroidic table and have electronic configuaration : `5f^(1-14)6d^(0-1)7s^(2)`. They include fourteen elements. These are known as actinoids since they occupy position in the periodic table after actinium of d-block (Z=89). Most of them are radioactive in nature. | |
| 463. |
Formula of chromyl chloride is-A. `CrPCL_(2)`B. `CrO_(2)Cl`C. `CrO_(2)Cl_(2)`D. `(CrOCl)_(2)` |
| Answer» Correct Answer - C | |
| 464. |
Identify the statement which is not correct regarding `CuSO_4`?A. It reacts with KI to give iodineB. It reacts with KCl to give `Cu_2Cl_2`C. It reacts with `NaOH` and glucose to give `Cu_2O`D. It gives `CuO` on stron heating in air |
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Answer» Correct Answer - b `CuSO_4` reacts with KI to give white ppt of `Cu_2I_2` but `CuSO_4` does not react with KCl to give `CuCl_2`. |
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| 465. |
The compound which gives oxygen on moderate heating isA. Zinc oxideB. Mercuric oxideC. Aluminium oxideD. Ferric oxide |
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Answer» Correct Answer - b `2HgOoverset(Delta)to2Hg+O_2` |
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| 466. |
`KMnO_(4)` can be prepared from `K_(2)MnO_(4)` as per reaction `3MnO_(4)^(2-)+2H_(2)OhArr2MnO_(4)^(-)+MnO_(2)+4OH^(-)`A. HClB. KOHC. `CO_(2)` is formed as the productD. `sO_(2)` |
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Answer» Correct Answer - D Since,`OH^(-)` are generated from weak acid`(H_(2)O)`. A weak acid (like `CO_(2)`) should be used to remove it because strong acid (HCl) reverse the reaction . KOH increases the concentration of `OH^(-)`,thus again sgifts the reaction in backward side . `Co_(2)` combines with `OH^(-)` to give carbonate which is easily removed. `SO_(2)`react with water to give strong acid , so it cannot be used. |
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| 467. |
Identify the metal that froms colourless compounds.A. Iron(Z=26)B. Chromium (Z=24)C. Vanadium (Z=23)D. Scandium(Z=21) |
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Answer» Correct Answer - D d-block elements show `+3` as the common oxidation state. For scandium (Z=21), electronic configuration is `d^(1)s^(2)`. After the remove of `3+` electrons `(Sc^(3+))`,it acquires a stable configuration `(d^(0))`. Hence, it froms colourless compounds. |
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| 468. |
Which of the following does not give oxygen on heating?A. `KClO_(3)`B. `Zn(ClO_(3))_(2)`C. `K_(2)Cr_(2)O_(7)` solution in acidic medium is orengeD. `(NH_(4))_(2)Cr_(2)O_(7)` |
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Answer» Correct Answer - D Oxygen rich compounds like chlorate , perchromate `K_(2)Cr_(2)O_(7)` ect., when heated gives oxygen but ammonium dichromate gives nitrogen gas. `2KClO_(3)overset(Delta)(rarr)2KCl+3O_(2)darr` `Zn(ClO_(3))_(2)overset(Delta)(rarr)ZnCl_(2)+3O_(2)darr` `4K_(2)Cr_(2)O_(7)overset(Delta)(rarr)4K_(2)CrO_(4)+2Cr_(2)O_(3)+3O_(2)uarr` `(NH_(4))_(2)Cr_(2)O_(7)overset(Delta)(rarr)N_(2)uarr+Cr\_(2)O_(3)+4H_(2)O` |
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| 469. |
The only radioactive element among the lanthanoids isA. gadoliniumB. holmiumC. promethiumD. neodynium |
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Answer» Correct Answer - C Among the lanthanoids, promethium is the only radioactive element. |
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| 470. |
Match the compounds `//` elements given in Column I with uses given in Column II `{:(,"Column I ( Compound/element)" ,,"Column II (Use)"),((i),"Lanthanoid oxide",(a),"Production ofiron alloy"),((ii) ,"Lanthanoid ",(b) ,"Television screen"),((iii), "Misch metal",(c ) ,"Petroleum cracking"),((iv),"Magnesium based alloy is constituent of ",(d) ,"Lanthanoid metal"+"iron"),((v) ,"Mixed oxides of lanthanoids are employed",(e ),"Bullets"),(,,(f),"In X-ray screen"):}` |
| Answer» Correct Answer - `(i) rarr(b), (ii) rarr(a), (iii) rarr (d), (iv) rarr (e ) , (v) rarr (c )` | |
| 471. |
Match the property given in Column I with the element given in Column II. `{:(,"Column I(Property)",,"Column II( Element)"),((i),"Lanthanoid which shows "+4"oxidation state",(a),P m),((ii),"lLnathanoid which can show "+2"oxidation state",(b),Ce),((iii),"Radiactive lanthaoid",(c ),Lu),((iv),"Lanthanoid which has "4f^(7)"electronic configuration in "+3"oxidation state",(d),Eu),((v),"Lanthanoid which has " 4f^(14) "electronic configuration in "+3"oxidation state",(e ) ,Gd),(,,(f ),Dy):}` |
| Answer» Correct Answer - `(i) rarr (b) , (ii) rarr (d) , (iii) rarr (a) , (iv) rarr (e ) , (v) rarr (c ) ` | |
| 472. |
Which is the most common oxidation state of lanthanides ? |
| Answer» Correct Answer - `+3` | |
| 473. |
Write any two uses of pyrophoric alloys. |
| Answer» Pyrophoric alloys emit sparks when struck. Hence, they are used in making flints for lighters and in making of bullets and shells. | |
| 474. |
Which is wrong about transition metals?A. They form complexesB. They show variable valencyC. All transition metla compounds are paramagneticD. They from coloured ions |
| Answer» Some transition metals are diamagnetic. | |
| 475. |
Which of the following ions is coloured in solution ?A. `Zn^(2+)`B. `Ti^(4+)`C. `Cu^(+)`D. `V^(2+)` |
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Answer» Correct Answer - D Among these, only `V^(2+)` contains unpaired electron. |
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| 476. |
The maximum magnetic moment is shown by the ion with electronic configurationA. `3 d^(8)`B. `3 d ^(5)`C. `3 d^(7)`D. `3 d^(9)` |
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Answer» Correct Answer - B `3d ^(5)` contains maximum unpaired electrons. |
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| 477. |
Which radical can bring about the highest oxidation state of a transition metal ?A. `F ^(-)`B. `Cl^(-)`C. `Br^(-)`D. `I^(-)` |
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Answer» Correct Answer - A `F^(-)` stabilize higher oxidation state of d-block elements. |
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| 478. |
A substance is found to have a magnetic moment of `3.9 ` B.M. Howmany unparied electrons does it contain ? |
| Answer» Using the formula, `mu = sqrt(n ( n+2)) B.M.,n = 3` | |
| 479. |
In `[Fe(CN)_5(NO)]^(2-)`, Fe has `+2` state. It cannot be dicided byA. Magnetic measurementB. Colligative propertyC. Colour HybridisationD. |
| Answer» Correct Answer - b,c,d | |
| 480. |
The highest oxidation state is shown by transition element s with electronic configurationA. `3d ^(8)4s^(2)`B. `3d^(5)4s^(1)`C. `3d^(5)4s^(2)`D. `3d^(3)4s^(2)` |
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Answer» Correct Answer - C Maximum unpaired electron = five. s-electrons =two. |
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| 481. |
Which is /are true statement?A. Ions of d-block elements are coloured due to d-d transition.B. Ions of f-block elements are coloured due to f-f transition.C. `[Sc(H_2O)_6]^(3+)`,`[Ti(H_2O)_6]^(4+)`, are coloured complexes.D. `Cu^(o+)` is colourless ion. |
| Answer» Correct Answer - a,b,d | |
| 482. |
The highest oxidation state shown by any transition element isA. 3B. 5C. 4D. 7 |
| Answer» Correct Answer - D | |
| 483. |
Copper can be regarded as a transition element only in the oxidation state isA. `-1`B. 0C. `+1`D. `+2` |
| Answer» Correct Answer - D | |
| 484. |
Coinage metals show the properties ofA. Typical elementsB. Normal elementsC. Transitional elementsD. Inert elements |
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Answer» Correct Answer - c Coinage metals `(Cu,Ag,Cu)` show the properties of transition elements. |
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| 485. |
What are coinage metals ? Give example . |
| Answer» Transition metals present in group 11 (Cu, Ag, Au) are known as coinage metals since they are used in making coins as well as jewellery. | |
| 486. |
Coinage metals show the properties ofA. alkaline earth metalsB. Transition metalsC. Inner transition metalsD. Noble metals |
| Answer» Correct Answer - B | |
| 487. |
`Cl_2` gas is obtained by various reactions select the reactions from the following (s):A. `KMnO_4+conc.HCloverset(Delta)to`B. `KCl+K_2Cr_2O_7+conc.H_2SO_4overset(Delta)to`C. `MnO_4+conc.HCloverset(Delta)to`D. `KCl+F_2overset(Delta)to` |
| Answer» Correct Answer - a,c,d | |
| 488. |
Formation of `Cl_2` gas is not possible in the reactionA. `KMnO_4 + ` conc. HClB. `MnO_2` + conc. HClC. `KCl + F_2`D. `K_2Cr_2O_7 + KCl` + conc. `H_2SO_4` |
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Answer» Correct Answer - D `K_2Cr_2 O_7 + 4KCl + 6H_2SO_4 to 2CrO_2 Cl_2 + 6KHSO_4 + 3H_2O` It does not give `Cl_2` |
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| 489. |
Which transition metal is different among the following ?A. CuB. HgC. MnD. Cr |
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Answer» Correct Answer - B Hg is a liquid metal wheres all other are solid |
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| 490. |
`Fe^(+3)`A. is isoelectronic with `Cu^(+2)`B. is isoelectronic with `Co^(+2)`C. is isoelectronic with `Mn^(+2)`D. is isoelectronic with `Ni^(+2)` |
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Answer» Correct Answer - C `Fe^(+3)` is isoelectronic with `Mn^(+2)` as both have same number of `e^-` and electronic configuration `Fe^(+3) (3d^5 4s^0) " " Mn^(+2) (3d^5 4s^0)` Electronic configuration of other ions are `Cu^(+2)(3d^9 4s^0) " "Co^(+2)(3d^7 4s^0) " " Ni^(+2) (3d^8 4s^0)` |
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| 491. |
Bell metal is an alloy ofA. Cu, Zn and SnB. Cu and SnC. Cu and ZnD. Sn and Zn |
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Answer» Correct Answer - B Bell metal is an alloy containing Cu and Sn . (Cu=80%, Sn=20%) |
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| 492. |
Identify A to E and also explain the reaction involved. |
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Answer» The substances from A to E are A = Cu, B = Cu`(NO_(3))_(2)`, C = `[Cu(NH_(3))_(4)]^(2+)`, D = `CO_(2)`, E = `CaCO_(3)` Reactions: (i) `CuCO_(3)overset(Delta)rarr CuO+CO_(2) xx2` (ii) `2CuO + CuS rarr underset([A])(3Cu) + SO_(2)` (iii) `underset ([A])(Cu) + 4HNO_(3) ("Conc.")rarr Cu underset([B])((NO_(3))_2)+2NO+2H_(2)O` (iv) `C underset([B])(u^(2+))+NH_(3) rarr undersetunderset(("Blue solution"))([C])([Cu(NH_(3))_(4)])` (v) `Ca(OH)_(2) + underset([D])(CO_(2)) rarr undersetunderset(("Milky"))([E]) (CaCO_(3)) + H_(2)O` (vi) `CaCO_(3) + H_(2)O + CO_(2) rarr Ca(HCO_(3))_(2)` |
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| 493. |
Assertion (A) Actinoids form relatively less stable complexes as compared to lanthanoids. Reason (R ) Actinoids can utilise their 5f orbitals alongwith 6d orbitals in bonding but lanthanoids do not use their 4f orbital for bonding.A. Both assertion and reason are true, and reason is the correct explanation of the assertion.B. Both assertion and reason are true but reason is not the correct explanation of assertion.C. Assertion is not true but reason is true.D. Both assertion and reason are false. |
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Answer» Correct Answer - C Assertion is not true but reason is true. Actinoids form relatively more stable complexes as compared to lanthanoids because of actinoids can utilise their 5f orbitals along with 6d orbitals in bonding but lanthanoids do not use their 4f orbitals for bonding. |
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| 494. |
Gas (A) and gas(B) both turn `K_(2)r_(2)O_(7)//H^(+)` green. Gas (A) alos turbs lead acetate paper black. When gas (A) is passed into gas (B) in ann aqueous solution, yellowish white turbidiyt appears. Identify gas (A) and (B) and explain the reactions. |
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Answer» The information suggest that the gas (A) is `H_(2)S` while the gas (B) is `SO_(2)`. Both turn acidified `K_(2)Cr_(2)O_(7)` paper green. `K_(2)Cr_(2)O_(7)+4H_(2)SO_(4)+underset("(Gas A)")(3H_(2)S) to K_(2)SO_(4) + underset("(green)")(Cr_(2)(SO_(4))_(3))+7H_(2)O+3(S)` `K_(2)Cr_(2)O_(7)+H_(2)SO_(4)+underset("(Gas B)")(3SO_(2)) to K_(2)SO_(4) + underset("(green)")(Cr_(2)(SO_(4))_(3))+H_(2)O` `underset("(Gas A)")(H_(2)S)+(CH_(3)COO)_(2)Pb to underset("(Black ppt.)")(PbS)+2CH_(3)COOH` `underset("(Gas A)")(2H_(2)S)+underset("(Gas B)")(SO_(2)) to 2H_(2)O+underset("(Yellowish turbidity )")(3S)` |
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| 495. |
When chromite ore `FeCr_(2)O_(4)` is fused with NaOH in presence of air, a yellow coloured compound ( A) is obtained which on acidification with dilute sulphuric acid gives a compound ( B). Compound (B) on reaction with KCl forms an orange coloured crystalline compound (C ) (i) Write the formulae of the compounds (A) , (B) and (C ) (ii) Write one use of compound (C ) . |
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Answer» (i) `4FeCr_(2)O_(4) + 16 NaOH + 7O_(2) rarr underset("(A)(Sodium chromate")(8 Na_(2)CrO_(4))+ 2Fe_(2)O_(3)+ 8 H_(2)O` `2Na_(2)CrO_(4) + H_(2)SO_(4) rarr underset("(B) Sodium dichromate")(Na_(2) Cr_(2)O_(7)) + Na_(2)SO_(4)+ H_(2)O` `Na_(2)Cr_(2)O_(7) + 2KCl rarr underset("(C ) Potassium dichromate")( K_(2)Cr_(2) O_(7)) + 2NaCl` (ii) Potassium dichromate is used as a powerful oxidizing agent in industries and in the tanning of leather. |
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| 496. |
Number of moles of `K_2Cr_2O_7` reduced by one mole of `Sn^(2+)` ion isA. `1/3`B. 3C. `1/6`D. 6 |
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Answer» Correct Answer - A `underset"1 M"(Cr_2O_7^(2-)) + 14H^(+) + 6e^(-) to 2Cr^(3+) + 7H_2O` `underset"1 M"(Sn^(2+)) to Sn^(4+) + 2e^-` 1 M of `Sn^(2+)` on oxidation gives `2e^-` `6e^-` reduce 1 M of `Cr_2O_7^(2-)` completely. Then `2e^-` will reduce `M/6xx2=M/6` i.e.`1/3` moles of `K_2Cr_2O_7` |
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| 497. |
Number of moles of `K_2Cr_2O_7` reduced by one mole of `Sn^(2+)` ion isA. `(1)/(3)`B. `3`C. `(1)/(6)`D. 6 |
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Answer» Correct Answer - a Eq. of `Cr_2O_7^(2-)=`Eq. of `Sn^(2+)` (`n` factor`=6`) (`n` factor`=6`) ltbr `(1)/(6)` mol. Of `Cr_2O_7^(2-)=(1)/(2)`mol. Of `Sn^(2+)` 1 mol of `Sn^(2+)=(2)/(6)=(1)/(3)` mol. Of `Cr_2O_7^(2-)` |
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| 498. |
Identify A to E and also explain the reaction involved. |
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Answer» Left hand side `CuCO_(3) overset("heat") toCuO+CO_(2)` `2CuO+CuS to underset((A))(3Cu)+SO_(2)` `Cu+4HNO_(3)(conc.) to underset((B))(Cu(NO_(3))_(2))+4NO_(2)+O_(2)` ` underset((B))(Cu^(2+))+4NH_(3)(aq) to underset("Blue solution (C)")([Cu(NH_(3))_(4)]^(2+))` Right hand side `CuCO_(3) overset(heat) to CuO+ underset((D))(CO_(2))` `Ca(OH)_(2)+ underset((D))(CO_(2)) to underset("Milky(E)")(CaCO_(3))+H_(2)O` `CaCO_(3)+H_(2)O+CO_(2) to underset("Clear solution (F)")(Ca(HCO_(3))_(2))` |
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| 499. |
Which of the following of manganese is amphoteric?A. `MnO_7`B. `Mn_2O_3`C. `Mn_2O_7`D. `MnO` |
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Answer» Correct Answer - a Acidic character of oxides increases when`O.S.` increases. Thus `MnO` and `Mn_2O_3` are basic. `MnO_2` is amphoteric and `Mn_2O_7` is acidic. |
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| 500. |
Reactivity of transition element decreases almost regularly from Sc to Cu. Explain. |
| Answer» Along a transition series, there is a gradual increase in the magnitude of ionisation enthalpy from left to the right. The reactivity of the metals is therefore, expected to decrease, | |