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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.
| 51. |
Which halides of the element of group `13` do not exist as dimer in the vapour state, the element isA. AlB. BC. GaD. Tl |
| Answer» Correct Answer - B | |
| 52. |
The trihalides of group `13` are hydrolysed by water and they fume in moist air due to theA. Formation of hydrogen halideB. Formation of haloboric acidC. Formation of halogen gasesD. None of the above |
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Answer» Correct Answer - A `BX_(3) + 3H_(2) O rarr B(OH)_(3) + 3HX (X = F, Cl, Br, I)`. |
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| 53. |
A white crystalline compound `(X)` swells open heating and gives violet-coloured flame. Its aqueous solution gives the following reactions : (a) A white precipitate is formed, with `BaCl_(2)` in presence of `HCl`. (b) When treated with excess of `NH_(4) OH`, it gives white gelatinous precipitate. the white precipitate dissolves in `NaOH` and reappears on boiling with concentrated solution of `NH_(4) Cl`. ( c) It gives yellow precipitate with cobaltinitrite solution. Identify `(X)` and explain the reaction at steps `a, b` and `c`. |
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Answer» The given compound `(X)` sweels on heating due to evolution of water molecules. It also, gives violet coloured flame due to the presence of potassium salt. The givem compound `(X)` is potash alum. `K_(2) SO_(4) .Al_(2) (SO_(4))_(3) .24 H_(2) O` which gives the following reactions : (a) With `BaCl_(2)` in presence of `HCl`, a white precipitate is formed. The aqueous solution contains `SO_(4)^(2-)` ions, which react with `Ba^(2+)` ions the give white precipitate of `BaSO_(4)`, which is insoluble in conc `HCl`. `Ba_((aq))^(+2)+ So_(4(aq))^(2-)rarr underset("White ppt.") (BaSO_(4) darr)`. (b) With excess of `NH_(4) OH`, white geletinous precipitate `Al_(2)(SO_(4))_(3) + 6NH_(4) OH rarr underset("White gelatinous precipitate") (2Al (OH)_(3) darr) + 3(NH_(4))_(2) SO_(4)` of aluminium hydroxide, `Al(OH)_(3)`, is formed. `Al(OH)_(3)` dissolves in `NaOH` forming sodium meta-aliminate. `Al(OH)_(3) + NaOH rarr underset("Sodium meta-aluminate (soluble)") (NaAlO_(2)) + 2H_(2) O` The white precipitate reappears when teh above soluble is boiled with concentrated soluble of `NH_(4) Cl`, due to the formation of white precipitate of aluminium hydroxide, `Al(OH)_(3)`. `NaAlO_(2) + NH_(4) Cl + H_(2) O rarr Al(OH)_(3) darr + NH_(3) + NaCl` ( c) Potassium salts give yellow precipitate of potassium cobaltinitrite with cobaltinitrite soluble. `2K_(2) SO_(4) + Na(4)[Co(NO_(4))_(6)] rarr underset ("Yellow ppt")(K_(4)[Co(NO_(2))_(6)]) darr + 2Na_(2) SO_(4)` or `4K^(oplus) +[Co(NO_(2))_(6)]^(4-) rarr underset("Potassium cobaltinitrite") (K_(4)[Co(NO_(2))_(6)] darr)`. |
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| 54. |
`H_(3)BO_(3)` is.A. Monobasic and weak Lewis acidB. Monobasic and weak Bronsted acidC. Monobasic and strong Lewis acidD. Tribasic and weak Bronsted acid. |
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Answer» Correct Answer - A `H_(3)BO_(3) + 3H_(2)O hArr [B(OH)_(4)]^(Ө) + H_(3)O^(oplus)`. |
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| 55. |
Correct match is :A. Ordinary form of borax : `Na_(2)B_(4)O_(7).5H_(2)O`B. Colemanite : `Ca_(2)B_(6)O_(11). 5H_(2)O`C. Beronarocalcite : `2Mg_(3) B_(8)O_(15). MgCl_(2)`D. Octahedral form of borax : `Na_(2)B_(4)O_(7). 10 H_(2) O`. |
| Answer» Correct Answer - B | |
| 56. |
alums are used for :A. Tanning of leatherB. Purification of waterC. CoagulationD. All of these |
| Answer» Correct Answer - D | |
| 57. |
`Al_(2)(SO_(4)_(3) + NH_(4)OH rarr X , X` is.A. A white gelatinous precipitateB. Soluble in excess of `NH_(4)OH`C. Soluble in excess of `NaOH`D. Amphoteric in nature. |
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Answer» Correct Answer - A::C::D `Al(SO_(4))_(3) + NH_(4) OH rarr (NH_(4))_(2) SO_(4) + Al(OH)_(3) X` is `Al(OH)_(3)`, which is a white gelatinous precipitate soluble in excess of `NaOH` and is amphoteric in nature. |
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| 58. |
A mixture of boron trichloride and hydrogen is subjected to silent electric discharge to form `(A)` and `HCl. (A)` is mixed with ammonia and heated to `200^@ C` to from `(B)`. Identify `(A)` and `(B)`. |
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Answer» `BCl_(3) +H_(2) overset("Silent electric discharge")rarr (A) + HCl` `(A) + NH_(3) overset(200^@C)rarr (B)` `2BCl_(3) + 6H_(2) overset("Silent electric discharge")rarr underset((A)) (B_(2)H_(6) ) + 6HCl` `3B_(2) H_(6) + 6NH_(3) overset(200^@C)rarr underset((B))(2B_(2) N_(3) H_(6)) + 12 H_(2)` `(A)` is diborane and `(B)` is borazine. |
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| 59. |
Choose the correct option : `BF_(3)` is used as a catalyst in several industrial processes due to its :A. Strong reducing natureB. Weak reducing natureC. Strong Lewis acid natureD. Weak Lewis acid character |
| Answer» `BF_(3)`, due to its strong Lewis acid nature, accepts a pair of electron from the donar molecule and thus behaves as a catalyst. | |
| 60. |
Borax is uded as a cleaning agent because on dissolving in water, it gives |
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Answer» Correct Answer - F Borax dissolves in water to give alkaline solution. |
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| 61. |
Borax is uded as a cleansing agent because on dissolving in water, it givesA. Alkaline solutionB. Acidic solutionC. Bleaching solutionD. Neutral solution |
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Answer» Correct Answer - A Borax dissolves in water to give an alkaline solution. `Na_(2)B_(4)O_(7) +7H_(2)O hArr 2NaOH + 4H_(3)BO_(3)`. |
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| 62. |
Boron reacts with oxygen at `700^@C` to give `(A)`. Compound `(A)` reacts with carbon and dry chloride to give `(B)` and carbon monoxide. `(B)` on reduction with `LiAlH_(4)` gives `( C)` along with `LiCl` and `AlCl_(3). ( C)` on reaction with ammonia gives `(D)`. Which on heating gives `(E).(C)` on reaction with `NaH` gives `(F)`. Compound `(E)` is.A. Inorganic benzeneB. BorazineC. BorazonD. Diborane |
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Answer» Correct Answer - A::B `B +O_(2) overset(700^@C)rarr (A)` `(A) +C+Cl_(2) rarr(B) + CO` `(B) +LiAlH_(4) rarr (C) + LiCl + AlCl_(3)` `(C) + NH_(3) overset(-120^@C)rarr (D)` `(D) overset(Delta) underset(200^@ C)rarr (E)` `(C) + NaH rarr (F)` `4B +3O_(2) overset(700^@ C)rarr underset((A))(2B_(2)O_(3))` `B_(2)O_(3) +3C +3Cl_(2) rarr underset((B))(2BCl_(3))+ 3CO` `underset((B)) (4BCl_(3)) + 3LiAlH_(4) rarr underset((C)) (2B_(2) H_(6)) + 3LiAl + 3AlCl_(3)` `B_(2)H_(6) +2NH_(3) overset (-120^@ C)rarr underset((D))([H_(2)B(NH_(3))_(2)]^(oplus) [BH_(4)]^(Ө))` `3[H_(2)B(NH_(3))_(2)]^(oplus) [BH_(4)]^(Ө) overset(200^@ C)rarr underset((E)) (2B_(3)N_(3)H_(6) + 8H_(2))` `B_(2)H_(6) + 2NaH rarr underset((F))(2NaBH_(4))`. Compound `(E)` is `B_(3)N_(3) H_(6)`, which is known as borazine. It is also known as inorganic benzene as it is isoelectronic acid isostructural to benzene. |
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| 63. |
Boron reacts with oxygen at `700^@C` to give `(A)`. Compound `(A)` reacts with carbon and dry chloride to give `(B)` and carbon monoxide. `(B)` on reduction with `LiAlH_(4)` gives `( C)` along with `LiCl` and `AlCl_(3). ( C)` on reaction with ammonia gives `(D)`. Which on heating gives `(E).(C)` on reaction with `NaH` gives `(F)`. Compound `(C)` isA. An electron-deficient compoundB. Contain `(3c, 2e)` bondC. Has ethane like structureD. An ionic compound. |
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Answer» Correct Answer - A::B `B +O_(2) overset(700^@C)rarr (A)` `(A) +C+Cl_(2) rarr(B) + CO` `(B) +LiAlH_(4) rarr (C) + LiCl + AlCl_(3)` `(C) + NH_(3) overset(-120^@C)rarr (D)` `(D) overset(Delta) underset(200^@ C)rarr (E)` `(C) + NaH rarr (F)` `4B +3O_(2) overset(700^@ C)rarr underset((A))(2B_(2)O_(3))` `B_(2)O_(3) +3C +3Cl_(2) rarr underset((B))(2BCl_(3))+ 3CO` `underset((B)) (4BCl_(3)) + 3LiAlH_(4) rarr underset((C)) (2B_(2) H_(6)) + 3LiAl + 3AlCl_(3)` `B_(2)H_(6) +2NH_(3) overset (-120^@ C)rarr underset((D))([H_(2)B(NH_(3))_(2)]^(oplus) [BH_(4)]^(Ө))` `3[H_(2)B(NH_(3))_(2)]^(oplus) [BH_(4)]^(Ө) overset(200^@ C)rarr underset((E)) (2B_(3)N_(3)H_(6) + 8H_(2))` `B_(2)H_(6) + 2NaH rarr underset((F))(2NaBH_(4))`. Compound `(c)` is `B_(2)H_(6)`, which is an electron-deficient compound and contains `(3c, 2e)` bonds. |
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| 64. |
Boron reacts with oxygen at `700^@C` to give `(A)`. Compound `(A)` reacts with carbon and dry chloride to give `(B)` and carbon monoxide. `(B)` on reduction with `LiAlH_(4)` gives `( C)` along with `LiCl` and `AlCl_(3). ( C)` on reaction with ammonia gives `(D)`. Which on heating gives `(E).(C)` on reaction with `NaH` gives `(F)`. Compound `(F)` behaves as.A. Reducing agentB. Oxidising agentC. ComplexonD. Buffer |
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Answer» Correct Answer - A `B +O_(2) overset(700^@C)rarr (A)` `(A) +C+Cl_(2) rarr(B) + CO` `(B) +LiAlH_(4) rarr (C) + LiCl + AlCl_(3)` `(C) + NH_(3) overset(-120^@C)rarr (D)` `(D) overset(Delta) underset(200^@ C)rarr (E)` `(C) + NaH rarr (F)` `4B +3O_(2) overset(700^@ C)rarr underset((A))(2B_(2)O_(3))` `B_(2)O_(3) +3C +3Cl_(2) rarr underset((B))(2BCl_(3))+ 3CO` `underset((B)) (4BCl_(3)) + 3LiAlH_(4) rarr underset((C)) (2B_(2) H_(6)) + 3LiAl + 3AlCl_(3)` `B_(2)H_(6) +2NH_(3) overset (-120^@ C)rarr underset((D))([H_(2)B(NH_(3))_(2)]^(oplus) [BH_(4)]^(Ө))` `3[H_(2)B(NH_(3))_(2)]^(oplus) [BH_(4)]^(Ө) overset(200^@ C)rarr underset((E)) (2B_(3)N_(3)H_(6) + 8H_(2))` `B_(2)H_(6) + 2NaH rarr underset((F))(2NaBH_(4))`. Compound `(F)` is `NaBH_(4)`, which behaves as a reducing agent. |
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| 65. |
The stability of monohalides of group `13` elementsA. Increases down the groupB. Decreases down the groupC. First increases and then decreasesD. First decreases and then increases |
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Answer» Correct Answer - A Due to inert pair effect, stability of lower oxidation state, i.e. `+1` increases down the group. |
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| 66. |
The stability of `+1` oxidation state increases in the sequence :A. `Tl lt In lt Ga lt Al`B. `In lt Tl lt Ga lt Al`C. `Ga lt In lt Al lt Tl`D. `Al lt Ga lt In lt Tl` |
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Answer» Correct Answer - D Due to the inert pair effect, group `13` elements show `+1` oxidation state also besides the group oxidation state `+3`, and the stability of lower oxidation state, i.e. `+1`, increases down the group `(darr)`. |
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| 67. |
Boron with hydrogen forms a number of hydrides which are known are boranes. These hydrides are classified into closoboranes and nidobarances. The simplest hydride of boron is diborane. Boron apart from having `(2c, 2e)` bonds also contain `(3c, 2e)` bonds. Three centre two electron `(3c, 2e)` bond is present in :A. `B_(2)H_(6)`B. `B_(2)H_(8)`C. `B_(2)H_(2)`D. `B_(2)H_(7)` |
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Answer» Correct Answer - A Diborane is closoborane with two boron atoms , hence, `B_(2) H_(6)`. |
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| 68. |
`"Colemanite" + Na_(2)CO_(3) overset("Fused")rarr (A) + (B) + CO_(2)` `underset("Solution")((A)) + CO_(2) rarr(B) + Na_(2) CO_(3)` `(B) + conc HCl rarr NaCl + underset("Acid")((C))` `underset("Acid")((C)) +H_(2)O rarr underset("Acid")((D))` `(D) overset("Strong heating")rarr (E)` `(E) +CuSO_(4) overset("Heated") underset("inflame")rarr underset("Blue-coloured compound")((F))`. Compound `(A)` is.A. `NaBO_(2)`B. `Na_(2)B_(4)O_(7)`C. `Na_(3)BO_(3)`D. `NaOH` |
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Answer» Correct Answer - A `underset("Colemanite") (Ca_(2)B_(6) O_(11)) + 2Na_(2)CO_(3) overset("Fused") rarr underset(underset("metaborate")("Sodium"))(NaBO_(2)) + underset((B))(Na_(2)B_(4)O_(7))+ 2CO_(2)` `underset((A))(NaBO_(2(aq))) + CO_(2) rarr underset((B))(Na_(2)B_(4)O_(7))+ Na_(2)CO_(3)` `underset((B))(Na_(2)B_(4)O_(7)) + underset("Conc")(HCl) rarr NaCl + underset((C))(H_(2) B_(4) O_(7))` `underset((C))(H_(2)B_(4)O_(7)) + 5H_(2)O rarr underset((D))(4H_(3)BO_(3))` `underset((D))(2H_(3)BO_(3)) overset("Strong") underset("heating") rarr underset((E))(B_(2)O_(3)) + 3H_(2)O` `underset((E))(B_(2)O_(3)) + CuSO_(4) overset("Heated in flame")rarr underset((F) "Blue coloured compound") (Cu(BO_(2))_(3))`. `NaBO_(2)`. |
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| 69. |
`"Colemanite" + Na_(2)CO_(3) overset("Fused")rarr (A) + (B) + CO_(2)` `underset("Solution")((A)) + CO_(2) rarr(B) + Na_(2) CO_(3)` `(B) + conc HCl rarr NaCl + underset("Acid")((C))` `underset("Acid")((C)) +H_(2)O rarr underset("Acid")((D))` `(D) overset("Strong heating")rarr (E)` `(E) +CuSO_(4) overset("Heated") underset("inflame")rarr underset("Blue-coloured compound")((F))`. Compound `(C)` is.A. `H_(2)B_(4)O_(7)`B. `HBO_(2)`C. `H_(3)BO_(3)`D. `H_(2)O` |
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Answer» Correct Answer - A `underset("Colemanite") (Ca_(2)B_(6) O_(11)) + 2Na_(2)CO_(3) overset("Fused") rarr underset(underset("metaborate")("Sodium"))(NaBO_(2)) + underset((B))(Na_(2)N_(4)O_(7))+ 2CO_(2)` `underset((A))(NaBO_(2(aq))) + CO_(2) rarr underset((B))(Na_(2)B_(4)O_(7))+ Na_(2)CO_(3)` `underset((B))(Na_(2)B_(4)O_(7)) + underset("Conc")(HCl) rarr NaCl + underset((C))(H_(2) B_(4) O_(7))` `underset((C))(H_(2)B_(4)O_(7)) + 5H_(2)O rarr underset((D))(4H_(3)BO_(3))` `underset((D))(2H_(3)BO_(3)) overset("Strong") underset("heating") rarr underset((E))(B_(2)O_(3)) + 3H_(2)O` `underset((E))(B_(2)O_(3)) + CuSO_(4) overset("Heated in flame")rarr underset((F) "Blue coloured compound") (Cu(BO_(2))_(3))`. `H_(2) B_(4)O_(7)`. |
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| 70. |
`"Colemanite" + Na_(2)CO_(3) overset("Fused")rarr (A) + (B) + CO_(2)` `underset("Solution")((A)) + CO_(2) rarr(B) + Na_(2) CO_(3)` `(B) + conc HCl rarr NaCl + underset("Acid")((C))` `underset("Acid")((C)) +H_(2)O rarr underset("Acid")((D))` `(D) overset("Strong heating")rarr (E)` `(E) +CuSO_(4) overset("Heated") underset("inflame")rarr underset("Blue-coloured compound")((F))`. Compound `(B)` is.A. `Na_(2)B_(4)O_(7)`B. `NaBO_(2)`C. `Na_(3)BO_(3)`D. `NaOH` |
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Answer» Correct Answer - A `underset("Colemanite") (Ca_(2)B_(6) O_(11)) + 2Na_(2)CO_(3) overset("Fused") rarr underset(underset("metaborate")("Sodium"))(NaBO_(2)) + underset((B))(Na_(2)N_(4)O_(7))+ 2CO_(2)` `underset((A))(NaBO_(2(aq))) + CO_(2) rarr underset((B))(Na_(2)B_(4)O_(7))+ Na_(2)CO_(3)` `underset((B))(Na_(2)B_(4)O_(7)) + underset("Conc")(HCl) rarr NaCl + underset((C))(H_(2) B_(4) O_(7))` `underset((C))(H_(2)B_(4)O_(7)) + 5H_(2)O rarr underset((D))(4H_(3)BO_(3))` `underset((D))(2H_(3)BO_(3)) overset("Strong") underset("heating") rarr underset((E))(B_(2)O_(3)) + 3H_(2)O` `underset((E))(B_(2)O_(3)) + CuSO_(4) overset("Heated in flame")rarr underset((F) "Blue coloured compound") (Cu(BO_(2))_(3))`. `Na_(2)B_(4)O_(7)`.] |
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| 71. |
`"Colemanite" + Na_(2)CO_(3) overset("Fused")rarr (A) + (B) + CO_(2)` `underset("Solution")((A)) + CO_(2) rarr(B) + Na_(2) CO_(3)` `(B) + conc HCl rarr NaCl + underset("Acid")((C))` `underset("Acid")((C)) +H_(2)O rarr underset("Acid")((D))` `(D) overset("Strong heating")rarr (E)` `(E) +CuSO_(4) overset("Heated") underset("inflame")rarr underset("Blue-coloured compound")((F))`. Compound `(E)` is.A. `B_(2)O_(3)`B. `B`C. `H_(3)BO_(3)`D. None of these |
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Answer» Correct Answer - A `underset("Colemanite") (Ca_(2)B_(6) O_(11)) + 2Na_(2)CO_(3) overset("Fused") rarr underset(underset("metaborate")("Sodium"))(NaBO_(2)) + underset((B))(Na_(2)N_(4)O_(7))+ 2CO_(2)` `underset((A))(NaBO_(2(aq))) + CO_(2) rarr underset((B))(Na_(2)B_(4)O_(7))+ Na_(2)CO_(3)` `underset((B))(Na_(2)B_(4)O_(7)) + underset("Conc")(HCl) rarr NaCl + underset((C))(H_(2) B_(4) O_(7))` `underset((C))(H_(2)B_(4)O_(7)) + 5H_(2)O rarr underset((D))(4H_(3)BO_(3))` `underset((D))(2H_(3)BO_(3)) overset("Strong") underset("heating") rarr underset((E))(B_(2)O_(3)) + 3H_(2)O` `underset((E))(B_(2)O_(3)) + CuSO_(4) overset("Heated in flame")rarr underset((F) "Blue coloured compound") (Cu(BO_(2))_(3))`. `B_(2)O_(3)`. |
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| 72. |
`"Colemanite" + Na_(2)CO_(3) overset("Fused")rarr (A) + (B) + CO_(2)` `underset("Solution")((A)) + CO_(2) rarr(B) + Na_(2) CO_(3)` `(B) + conc HCl rarr NaCl + underset("Acid")((C))` `underset("Acid")((C)) +H_(2)O rarr underset("Acid")((D))` `(D) overset("Strong heating")rarr (E)` `(E) +CuSO_(4) overset("Heated") underset("inflame")rarr underset("Blue-coloured compound")((F))`. Compound `(F)` is.A. `CuS`B. `Cu_(2)O`C. `CuSO_(3)`D. `Cu(BO_(2)_(3)` |
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Answer» Correct Answer - D `underset("Colemanite") (Ca_(2)B_(6) O_(11)) + 2Na_(2)CO_(3) overset("Fused") rarr underset(underset("metaborate")("Sodium"))(NaBO_(2)) + underset((B))(Na_(2)N_(4)O_(7))+ 2CO_(2)` `underset((A))(NaBO_(2(aq))) + CO_(2) rarr underset((B))(Na_(2)B_(4)O_(7))+ Na_(2)CO_(3)` `underset((B))(Na_(2)B_(4)O_(7)) + underset("Conc")(HCl) rarr NaCl + underset((C))(H_(2) B_(4) O_(7))` `underset((C))(H_(2)B_(4)O_(7)) + 5H_(2)O rarr underset((D))(4H_(3)BO_(3))` `underset((D))(2H_(3)BO_(3)) overset("Strong") underset("heating") rarr underset((E))(B_(2)O_(3)) + 3H_(2)O` `underset((E))(B_(2)O_(3)) + CuSO_(4) overset("Heated in flame")rarr underset((F) "Blue coloured compound") (Cu(BO_(2))_(3))`. `Cu(BO_(2)_(3)`. |
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| 73. |
`"Colemanite" + Na_(2)CO_(3) overset("Fused")rarr (A) + (B) + CO_(2)` `underset("Solution")((A)) + CO_(2) rarr(B) + Na_(2) CO_(3)` `(B) + conc HCl rarr NaCl + underset("Acid")((C))` `underset("Acid")((C)) +H_(2)O rarr underset("Acid")((D))` `(D) overset("Strong heating")rarr (E)` `(E) +CuSO_(4) overset("Heated") underset("inflame")rarr underset("Blue-coloured compound")((F))`. Compound `(D)` is.A. `H_(2)B_(4)O_(7)`B. `HBO_(2)`C. `H_(3)BO_(3)`D. `H_(2)O` |
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Answer» Correct Answer - C `underset("Colemanite") (Ca_(2)B_(6) O_(11)) + 2Na_(2)CO_(3) overset("Fused") rarr underset(underset("metaborate")("Sodium"))(NaBO_(2)) + underset((B))(Na_(2)N_(4)O_(7))+ 2CO_(2)` `underset((A))(NaBO_(2(aq))) + CO_(2) rarr underset((B))(Na_(2)B_(4)O_(7))+ Na_(2)CO_(3)` `underset((B))(Na_(2)B_(4)O_(7)) + underset("Conc")(HCl) rarr NaCl + underset((C))(H_(2) B_(4) O_(7))` `underset((C))(H_(2)B_(4)O_(7)) + 5H_(2)O rarr underset((D))(4H_(3)BO_(3))` `underset((D))(2H_(3)BO_(3)) overset("Strong") underset("heating") rarr underset((E))(B_(2)O_(3)) + 3H_(2)O` `underset((E))(B_(2)O_(3)) + CuSO_(4) overset("Heated in flame")rarr underset((F) "Blue coloured compound") (Cu(BO_(2))_(3))`. `H_(3)BO_(3)`. |
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| 74. |
What is the value of `x` in colemanite, `Ca_(2)B_(x)O_(11).6H_(2)O` ? |
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Answer» Correct Answer - `(6)` Colemanite is `Ca_(2)B_(6)O_(11) . 6H_(2) O`. |
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| 75. |
The chemical formula of feldspar isA. `KAlSi_(3)O_(8)`B. `Na_(3)AlF_(6)`C. `NaAIO_(2)`D. `K_(2)SO_(4). Al_(2)(SO_(4))_(3). 4 Al(OH)_(3)`. |
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Answer» Correct Answer - A Feldspar is `KAlSi_(3) O_(8)`. |
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| 76. |
`Al_(2)O_(3)` can be converted to anhydrous `AlCl_(3)` by heating :A. A mixture of `Al_(2)O_(3)` and carbon in dry `Cl_(2)` gas.B. `Al_(2)O_(3)` with `HCl` gasC. `Al_(2)O_(3)` with `Cl_(2)` gasD. `Al_(2)O_(3)` with `NaCl` in solid state |
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Answer» Correct Answer - A `Al_(2)O_(3)+3C+3Cl_(2) rarr 2AlCl_(3)+ 3CO`. |
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| 77. |
The liquified metal expanding on solidification is :A. AlB. GaC. ZnD. Cu |
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Answer» Correct Answer - B `Ga` is a solf silvery white metals and is liquid at room temperature. When it solidifies, it expands by `3.1 %` Therefore, it should not be stored in glass or metal containers. |
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| 78. |
What do you understand by : (a) Ammonal (b) Bentonite ( c) Rubies and Sapphire (d) Laps lazuli ( e) Emery paper. |
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Answer» (a) Ammonal : It is a mixture of aluminium and ammonium nitrate and is used in bombs. (b) Bentonite : It is alumina-silca clay and is dropped frm aeroplanes in the slurry form over an area designted for fire suppression, i.e it is used as fire retardant. ( c) Rubies and sapphire aluminium silicate and is used as semiprecious stone. (d) Lapis lazuli : It is sodium aluminium silicate and is used as semiprecious stone. ( e) Emery paper : Impure from of corundum `(Al_(2)O_(3))` containing impurity of `Fe_(2) O_(3)` silica is called emery and is used in the manufacture of emery parper or sandpaper. This paper is used is used to polish metal. |
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| 79. |
The heavier members of `13` and `14` groups besides the group oxidation state also show another oxidation state. Down the group `(darr)`, the stability of higher oxidation state increases. This concept which is commonly called inert pair effect has been used to explain many physical and chemical properties of the element of these groups. Heavier members of group `13` exhibit oxidation state.A. `+3` onlyB. ` +1` onlyC. `+1` and `+ 3` bothD. `+1,+2, +3` |
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Answer» Correct Answer - C Due to the inert pair effect, heavier members of group `13` exhibit `+3` (group oxidation state) and `+1` oxidation states. |
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| 80. |
The heavier members of `13` and `14` groups besides the group oxidation state also show another oxidation state. Down the group `(darr)`, the stability of higher oxidation state increases. This concept which is commonly called inert pair effect has been used to explain many physical and chemical properties of the element of these groups. Which among the following is the strongest oxidising agent ?A. `SiO_(2)`B. `GeO_(2)`C. `SnO_(2)`D. `PbO_(2)` |
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Answer» Correct Answer - D Oxidation state of `Pb` in `PbO_(2)` is `+4`. Due to inert pair effect, down the group `(darr), +2` oxidation state is more stable than `+4` oxidation state. `PbO_(2) rarr PbO + O_(2)`. Hence, `PbO_(2)` behaves as strongest reducing agent. |
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| 81. |
`(3c, 2e)` bond is present inA. `B_(2)H_(6)`B. `BCl_(3)`C. `Al_(2)Cl_(6)`D. `NH_(3)` |
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Answer» Correct Answer - A `B_(2) H_(6)` contains `(3c, 2e)` bond. |
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| 82. |
Aluminium acts as an oxidising agent. Aluminium gas a strong afinity for oxygen. |
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Answer» Correct Answer - D Correct assertion : Aluminium acts as a reducing agent. |
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| 83. |
Corundum is an ore of aluminium. |
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Answer» Correct Answer - `Al_(2)O_(3)` `Al_(2)O_(3)` |
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| 84. |
In which of the following, a salt of the type `KMO_(2)` is obtained ?A. `B_(2)H_(6) + KOH_((aq)) rarr`B. `Al + KOH_((aq)) rarr`C. BothD. None |
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Answer» Correct Answer - C `B_(2)H_(6) +2KOH +2H_(2)O rarr underset(underset("metaborate")("Potassium"))(2KBO_(2))+ 6H_(2)` `2Al +2KOH +2H_(2)O rarr underset(underset("metaborate")("Potassium"))(2KAlO_(2))+ 3H_(2)`. |
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| 85. |
Answer the following : (a) Name of element of group `13` which forms the most stable compound in `+1` oxidation state. (b) Name the element of group `13` which has the highest first ionisation enthalpy. ( c) Name the element of group `13` which is used as a reducing agent in metallurgical processes. (d) Name of element of group `13` which can show convalency maximum of four only. Name the compound of aluminium which is used as a germicide and coagulant of the purification of water. (f) Name the first two elements of group `13`. |
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Answer» (a) Thallium (b) Boron ( c) Aluminium (d) Boron (d) Boron ( e) Potash alum, `K_(2) SO_(4) Al_(2) (SO_(4))_(3) .24 H_(2) O` (f) Boron and aluminium. |
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| 86. |
The `+1` oxidation state is more stable than `+3` oxidation state for thallium. Give reason. |
| Answer» Electronic configuration of thallium is `[Xe]4f^(14) 5d^(10) 6s^(2) 5p^(1)`. Due to the presence of fully filled lesser shieling `4f^(14)` and `5d^(10)` orbitals between the valence shell and noble gas core, the valence shell electrons are more tightly bound of the nucleus , hence, it is difficult to unpair `6s^(2)` effect. This gives rise to inert pair effect. Therefore, `6s^(2)` electrons are less reactive and do not participate in the chemical bond formation. Hence, in thallium, `+1` oxidation state in more stable than `+3` oxidation state. | |
| 87. |
Why boron does not exist as `B^(2+)` ion in solution or in compound ? |
| Answer» Boron has three electrons in its valence shell `(3s^(2) 3p^(1))`. The sum of the first three ionisation enthalpies for boron is very high. Thus, the total energy required to produce `B^(3+)`ion is much more than would be compensated by the hydration enthlpy, and hence `B^(3+)` ion does not exist. The sum of the first three ionistion enthalpies is also not overcome by the lattice enthalpy of the compound in the solid state, and hence `B^(3+)` ion does not exist in the compound. | |
| 88. |
alums are used for :A. Purification of water and styptic to arrest bleedingB. Mordant in dyeing and in calico printingC. In tanning of leather, for sizing of paper and in fire extinguishersD. All of the above |
| Answer» Correct Answer - D | |
| 89. |
How can the following reaction be made to proceed in forward direction ? `B(OH)_(3) + NaOH hArr Na[B(OH)_(4)]`.A. By addition of `cis-1,2-diol`.B. Addition of boraxC. Addition of `trans-1,2-diol`D. Addition of `Na_(2)HPO_(4)`. |
| Answer» Correct Answer - A | |
| 90. |
When orthoboric acid is heated to red heat the residue is |
| Answer» Correct Answer - T | |
| 91. |
When orthoboric acid is heated to red heat the residue isA. BoronB. Boron oxideC. Pyroboric acidD. Metaboric acid |
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Answer» Correct Answer - B `2H_(3)BO_(3) overset("Red heat")rarr B_(2)O_(3) +3H_(2)O`. |
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| 92. |
`AlCl_(3)` on hydrolysis gives ______. |
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Answer» Correct Answer - `Al(OH)_(3)` `Al(OH)_(3)` |
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| 93. |
Inorganic graphite isA. `B_(3)N_(3)H_(6)`B. `B_(3)N_(3)`C. `SiC`D. `P_(4)S_(3)` |
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Answer» Correct Answer - B Inorganic graphite is boron nitride. |
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| 94. |
`BN` is known as inorganic benzene. |
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Answer» Correct Answer - `BN` `BN` |
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| 95. |
Which of the following oxides are basic ?A. `B_(2)O_(3)`B. `Tl_(2)O`C. `In_(2)O_(3)`D. `Al_(2)O_(3)` |
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Answer» Correct Answer - B::C `Tl` and `In` are metallic, their oxides are basic in nature. |
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| 96. |
Boric acid is tribasic acid. Boric acid contains three hydroxyl groups. |
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Answer» Correct Answer - d Boric acid, `B(OH)_(3)`. |
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| 97. |
Gernan silver is an alloy of aluminium. |
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Answer» Correct Answer - F German silver is an alloy of `60 % Cu, 20 % Ni` and `20 % Zn`. |
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| 98. |
In the correct of the Hall-Heroult process for the extraction of `Al`, which of the following statements is false ?A. `CO` and `CO_(2)` are produced in this processB. `Al_(2)O_(3)` is mixed with `CaF_(2)` which lowers the melting point of the mixture and brings conductivityC. `Al^(3+)` is reduced at the cathode to form `Al`.D. `Na_(3)AlF_(6)` serves as the electrolyte. |
| Answer» Correct Answer - D | |
| 99. |
Borax bead test is based upon the formation ofA. MetaborateB. TetraborateC. Double oxideD. Orthoborate |
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Answer» Correct Answer - A Borax on heating gives `B_(2)O_(3)` (transparent glassy bead). When hot `B_(2)O_(3)` is brought in contact with coloured salt, metaborates are formed. `Na_(2)B_(4)O_(7).10H_(2)O overset(Delta)rarr B_(2)O_(3) overset("Coloured") underset("substance")rarr Metaborate`. |
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| 100. |
What happens when : (a) Borax is heated strongly. (b) Water is added to aluminium nitride. ( c) Dry chlorine gas is added over not mixture of aluminium and coke. (d) Water is added to aluminium carbide. ( e) Alum is heated. (f) Aluminium is added to copper sulphate solution . (g) Aluminium reacts with `HNO_(3)`. (h) Excess of Excess of caustic soda is added to a solution aluminium chloride. (i) Aluminium is heated with caustic soda solution. (j) A mixture of borax and cobalt oxide is heated. |
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Answer» (a) `underset("Borax")(Na_(2)B_(4) O_(7)).10 H_(2) O overset(Delta)rarr Na_(2) B_(4) O_(7) + 10 H_(2) O` `Na_(2) B_(4) O_(7) overset(Delta) rarr underset("Boric anhydride") (B_(2) O_(3)) + underset ("Sodium metaborate") (2NaBO_(2))` (b) `underset("Aliminium nitrate") (AlN) + 3H_(2) O rarr underset("Alminium hydroxide") (B_(2) (OH)_(3)) darr + underset("Ammonia") (NH_(3)) uarr` ( c) `Al_(2)O_(3) + 3C + underset("Dry")(3 Cl_(2)) rarr underset("Aluminium chloride") (2AlCl_(3)) + underset("Carbon monoxide") (3CO)` (d) `underset("Aluminium carbide") (Al_(4) C_(3)) + 12H_(2) O rarr underset("Aluminium hydroxide") (4 Al(OH)_(3)) darr + underset("Methane") (3CH_(4)) uarr` (e) `K_(2) SO_(4). Al_(2) (SO_(4))_(3). 24H_(2) O overset(200^@ C)rarr K_(2) SO_(4) Al_(2) (SO_(4))_(3) + 24 H_(2) O` `K_(2) SO_(4).Al_(2) (SO_(4))_(3) overset("Red heat")rarr underset("Burnt alum")underbrace(K_(2) SO_(4) +Al_(2) O_(3)) + 3SO_(3) uarr`. Alum metls and loses water of crystallisation up to `200^@ C` and a white porus mass is obtained on red heat. This white mass is known as burnt alum. (f) Aluminium being more electropositive than copper, displaces copper from copper sulphite solution. `2Al_((s)) + 3 CuSO_(4(aq)) rarr Al_(2) (SO_(4))_(3(aq)) + 3Cu_((s))` (g) `HNO_(3)` whether concentrated or dilute hardly affects `Al` as aluminium is rendered passive due to formation of thin layer of `Al_(2) O_(3)` on the surface of the metal. (h) `AlCl_(3) + 3NaOH rarr Al(OH)_(3) + 3NaCl` (i) `2Al + 2NaOH + 2H_(2) O rarr underset ("Sodium metaluminate") (2NaAlO_(2)) + 2H_(2) uarr` (j) `Na_(2) B_(4) O_(7). 10 H_(2) O overset(Delta) rarr Na_(2) B_(4) O_(7) + 10 H_(2)O` `Na_(2) B_(4) O_(7) overset("Red heat") rarr NaBO_(2) + B_(2) O_(3)` `CoO + B_(2) O_(3) rarr underset("Cobalt metaborate")(Co(CO_(2))_(2))`. |
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