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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. |
The dimerisation of `NO_2` as the temperature is lowered and accompanied byA. an increase in pressureB. a darkening in pressureC. a decrease in ParamagnetismD. the formation of a colloid |
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Answer» Correct Answer - C The unpaired electron get paired up. |
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| 52. |
When phosphorus reacts with caustic soda, the products are `PH_(3) and NaH_(2)PO_(2)` This reaction is an example of:A. OxidationB. ReductionC. Oxidation and reductionD. Neutralisation |
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Answer» Correct Answer - C `3NaOH+P_(4)+3H_(2)O to PH_(3) +3NaH_(2)PO_(2)` This reaction involves simultaneous oxidation and reduction of P (oxidation of P to `NaH_(2)PO_(2)` and reduction to `PH_(3)`). |
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| 53. |
`Na_2 O` and `P_4 O_(10)` on heating at `1000^@C` yieldsA. Sodium tripolyphosphate : `Na_(5)P_(3)O_(10)`B. Sodium tripolyphosphate : `Na_(5)P_(3)O_(10).6H_(2)O`C. sodium dihydrogenphosphate : `Na_(2)HPO_(4)`D. Sodium hydrogenphosphate: `Na_(2)HPO_(4)` |
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Answer» Correct Answer - A `Na_(5)P_(3)O_(10)` |
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| 54. |
Which of the following does not give `NO_2` on heating?A. `KNO_(3)`B. `Pb(NO_(3))_(2)`C. `Cu(NO_(3))_(2)`D. `AgNO_(3)` |
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Answer» Correct Answer - A `2KNO_(3) overset(Delta) to 2KNO_(2) +O_(2)` All other nitrates give `NO_(2)` on heating |
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| 55. |
The total number of the oxidation states of P in compounds obtained on diproportionation of phosphorus acid is........ |
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Answer» Correct Answer - 2 `4H_(3)PO_(3) to 3H_(3)overset(+5)(PO_(4))+overset(-3)(PH_(3))` `:.` Sum of oxidation states in its compounds =+5-3 =+2 |
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| 56. |
Find the number of metals which are commercially reduced by self-reduction from the given metals : `Fe, Al, Z, Sn, Pb, Hg, Cu`. |
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Answer» Correct Answer - 4 Fe ,Cr , Ni and Al become passive when dipped in conc. `HNO_(3)` |
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| 57. |
Excess of `PCl_5` reacts with `conc. H_2 SO_4` givesA. sulphuryl chlorideB. sulphur dioxideC. chlorosuphuric acidD. thionyl chloride |
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Answer» Correct Answer - A `PCl_(5) +H_(2)SO_(4) to SO_(2)Cl_(2) +2POCl_(3)+2HCl`. |
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| 58. |
High heat of varporization of ammonia is due to itsA. basic natureB. polar structureC. hydrogen bondingD. high solubility |
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Answer» Correct Answer - C Due to hydrogen bonding, `NH_(3)` is associated so it has high heat of vaporization. |
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| 59. |
In which pair of compounds, the oxidation state of nitrogen is -1?A. Ammonia , hydroxylamineB. Nitric oxide , nitrnic acidC. Hydrazine , ammoniaD. Hydrazine ,hydroxylamine. |
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Answer» Correct Answer - D Both in `N_(2)H_(4)` and `NH_(2)OH` , O.N of N is -1 |
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| 60. |
Chlorine reacts with excess of ammonia to form.A. `NH_(4)Cl`B. `N_(2)+HCl`C. `N_(2)+NH_(4)Cl`D. `N_(2)+NCl_(3)` |
| Answer» Correct Answer - C | |
| 61. |
The high value of `Delta H_(vap)` of ammonia is attributed to itsA. basic natureB. Association due to H - bondingC. ShapeD. Covlent nature of N - H bonds |
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Answer» Correct Answer - B Association due to H-bonding is the reason for the high value of vaporization of ammonia. |
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| 62. |
When ammonia and sodium hypochloride are allowed to react, which nitrogen compound is formed?A. `NH_(4)Cl`B. `NH_(2)OH`C. `NH_(2)-NH_(2)`D. `N_(2)` |
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Answer» Correct Answer - C `2NH_(3) + NaCl to NH_(2) -NH_(2) +NaCl +H_(2)O` |
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| 63. |
A mixure of ammonia and air at about `800^(@)C` in the presence of `Pt` gauze formsA. `N_(2)O`B. NOC. `NH_(2)OH`D. `N_(2)O_(3)` |
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Answer» Correct Answer - B `4NH_(3) +5O_(2) overset(800^(@)C)undert(Pt)to4NO +6H_(2)O` |
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| 64. |
Super phosphate of lime containsA. `Ca_(3)(PO_(4))_(2)`B. `CaHPO_(4)`C. `Ca_(3)(PO_(4))_(2)+H_(3)PO_(4)`D. `Ca(H_(2)PO_(4))_(2)` |
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Answer» Correct Answer - D `Ca(H_(2)PO_(4))_(2)` |
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| 65. |
When on excess of chlorine is treated with ammonia ,the products formed areA. `N_(2)` and `NCl_(3)`B. `N_(2) ` and HClC. `N_(2)` and `NH_(4)Cl`D. `NCl_(3)` and HCl |
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Answer» Correct Answer - D `NH_(3)+underset("(Excess)")(3Cl_(2))toNCl_(3)+3HCl` |
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| 66. |
Which of the following is a cyclic phosphate?A. `H_(3)P_(3)O_(10)`B. `H_(6)P_(4)O_(13)`C. `H_(5)P_(5)O_(15)`D. `H_(7)P_(5)O_(16)` |
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Answer» Correct Answer - C Cyclic phosphate have a general formula of `(HPO_(3))_(n)` . Therefore, `H_(5)P_(5)O_(15)` represent a cyclic phosphate. |
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| 67. |
The reaction of calcined phosphate rock with coke and sand in an electric arc furnace at 1773 K gives a number of products includingA. PhoshorusB. SiliconC. Calcium hydrideD. Calcium oxide |
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Answer» Correct Answer - A `{:(Ca_(3)(PO_(4))_(2)+5C+3SiO_(2)),("Phosphate rock"),(" "3CaSiO_(3)+P uarr+5CO uarr),(" Slag"):}` |
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| 68. |
In modern proces, white phosphorus is manufactured by :A. Heating a mixture of phoshorite mineral with sand and coke in an electric furnaceB. Heating calcium phosphate with limeC. Heating bone ash with cokeD. Heating phosphate mineral with sand |
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Answer» Correct Answer - A White phosphorus is obtained by heating a mixture of phosphorite mineral, `Ca_(3)(PO_(4))_(2)` with sand and coke in an electric furnance. |
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| 69. |
Phosphorus is manufactured by heating in a furnaceA. Bone ash , Sodium chloride and cokeB. Bone ash , silica and cokeC. Bone ash , silica and limeD. Bone ash , coke and lime stone |
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Answer» Correct Answer - B `2Ca_(3)(PO_(4))_(2) +6SiO_(2) overset(Delta)to 6CaSiO_(3) +P_(4)O_(10)` `P_(4)O_(10) +10C overset(Delta)toP_(4) +10CO` |
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| 70. |
When ammonia is heated with cupric oxide, a molecule of ammonia willA. Gain 3 electrousB. Lose 3 electronsC. Gain 2 electronsD. Lose 2 electrons |
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Answer» Correct Answer - B `2NH_(3)+3CuO to N_(2)+H_(2)O +3Cu` `underset("( O.S.=-3)")(2NH_(3)) to underset("(O.S.=0)")(N_(2))` Thus each N atoms (or each `NH_(3)` molecule) loses 3 electrons |
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| 71. |
Metaphosphoric acid has the formulaA. `H_(3)PO_(4)`B. `HPO_(3)`C. `H_(3)PO_(3)`D. `H_(3)PO_(2)` |
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Answer» Correct Answer - B `HPO_(3)` is metaphosphoric acid. |
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| 72. |
Which of the following is metaphosphoric acid?A. `H_(3)P_(3)O_(9)`B. `H_(5)P_(3)O_(10)`C. `H_(9)P_(2)O_(7)`D. `H_(3)PO_(4)` |
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Answer» Correct Answer - A Metaphosphoric acid is `H_(3)P_(3)O_(9)` or `(HPO_(3))_(3)` |
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| 73. |
The compound of nitrogen in which nitrogen shows -3 oxidation state isA. `NF_(3)`B. `NH_(3)`C. `NCl_(3)`D. `N_(2)O_(3)` |
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Answer» Correct Answer - D Because nitrogen is more electronegative than hydrogen |
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| 74. |
Which of the following members of nitrogen family does not show negative oxidation state?A. PB. AsC. SbD. Bi |
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Answer» Correct Answer - B Bi because of very less electronegativity. |
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| 75. |
The low reactivity of nitrogen is due toA. small atomic radiusB. high electroguativityC. stable configurationD. high dissociation energy |
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Answer» Correct Answer - D High bond dissociation energy (945 kJ/mole) due to strong triple bond. |
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| 76. |
Which of the following is the strongest reducing agent?A. `NH_(3)`B. `PH_(3)`C. `N_(2)H_(2)`D. `N_(2)H_(4)` |
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Answer» Correct Answer - D `N_(2)H_(4)`, the hydrazine is the strongest reducing agent. |
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| 77. |
The oxidation state of phosphorus in `Ba(H_2 PO_2)_2` isA. 3B. 2C. 1D. -1 |
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Answer» Correct Answer - C Let O.N. of P=x In `Ba(H_(2)PO_(2))_(2)` O.N. of Ba =+2, O.N of H =+1, O.N. of O =-2 `:. 2+2[2xx1+x+2(-2)]=0` `2+2[2+x-4]=0` `2+2[x-2]=0` x=1 |
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| 78. |
Ammonia can be dried by `:`A. Conc. `H_(2)SO_(4)`B. `P_(4)O_(10)`C. CaOD. Anhy. `CaCl_(2)` |
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Answer» Correct Answer - C `NH_(3)` (a base) cannot be dried with conc. `H_(2)SO_(4)` (an acid ) or `P_(4)O_(10)` (an acidic oxide ). It cannot be even be dried with `CaCl_(2)` as it forms an addition complex compound with `CaCl_(2)`. Thus, `NH_(3)` case only be dried with CaO. |
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| 79. |
With respect to protonic acids, which of the following statements is correct?A. `PH_(3)` is more basic than `NH_(3)`B. `PH_(3)` is less basic than `NH_(3)`C. `PH_(3)` is equally basic as `NH_(3)`D. `PH_(3)` is amphoteric while `NH_(3)` is basic. |
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Answer» Correct Answer - B `PH_(3)` is less basic than `NH_(3)` due to lesser availibity of lone pair of electrons. |
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| 80. |
Phosphine is prepared by the action ofA. P and `H_(2)SO_(4)`B. P and NaOHC. P and `H_(2)S`D. P and `HNO_(3)` |
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Answer» Correct Answer - B `P_(4)+3NaOH+3H_(2)O to PH_(3) +3NaH_(2)PO_(2)` |
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| 81. |
Phosphine is generally prepared in the laboratoryA. By heating phosphorus in a current of hydrogenB. By decomposition of `P_(2)H_(4)` at 110C. By heating red phosphorus with an aquesous solution of caustic sodaD. By heating white phosphors with caustic potash |
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Answer» Correct Answer - D `underset("White or yellow")(P_(4)) +3KOH +3H_(2)O to underset("Potassium hypophosphite")(3KH_(2)PO_(2))+PH_(3)` |
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| 82. |
In the manufacture of safety matches we useA. White phosphorusB. Red phosphorusC. black phosphorusD. Selenium |
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Answer» Correct Answer - B Red phosphorus is used in safety matches, white phosphorus due to its low ignition temperature is not used. |
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| 83. |
Red phosphorus is less reactive than yellow phosphorus becauseA. Its colour is redB. It is insoluble in `C Cl_(4) `C. It is hardD. It is highly polymerised |
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Answer» Correct Answer - D Because it has a polymeric structure. |
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| 84. |
Which of the following has the least bond angle?A. `H_(2)O`B. `H_(2)S`C. `H_(2)Se`D. `H_(2)Te` |
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Answer» Correct Answer - D In `P_(4)` , P is `sp^(3)` hybridized. Hence `pi` character of p-orbitals is 75 % |
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| 85. |
Which one of the following oxides of nitrogen is a white solid?A. NOB. `NO_(2)`C. `N_(2)O_(3)`D. `N_(2)O_(5)` |
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Answer» Correct Answer - D `N_(2)O_(5)` is a white solid white NO and `NO_(2)` are gases. |
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| 86. |
On heating ammonium dichromate, the gas evolved is :A. OxygenB. ammoniaC. nitrous oxideD. nitrogrn |
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Answer» Correct Answer - D `(NH_(4))_(2) Cr_(2)O_(7) overset(Delta)to Cr_(2)O_(3)+N_(2)+4H_(2)O` |
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| 87. |
Which of the following is a tetrabasic acid?A. Orthphosphric acidB. Hypohosphorus acidC. Metaphosphoric acidD. Pyrocphoshoric acid |
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Answer» Correct Answer - D Pyrophosphoric acid is tetra-basic with four OH bond. `underset("Pyrophosphoric acid")(HO-overset(O)overset(||)underset(OH)underset(|)(P)-O-overset(O)overset(||)underset(OH)underset(|)(P)-OH)` |
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| 88. |
Which of the following is not hydrolysedA. `AsCl_(3)`B. `PF_(3)`C. `SbCl_(3)`D. `NF_(3)` |
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Answer» Correct Answer - D Neither N nor F has d-orbitals to accept electrons. |
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| 89. |
Which statement is wrong for `NO`?A. It is anhydrous of nitrous acidB. Its dipole moment is 0.22 DC. It forms dimerD. It is parmagnetic |
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Answer» Correct Answer - A `N_(2)O_(3)` but not NO is the anhydride of nitrous acid `2HNO_(2) to N_(2)O_(3) +H_(2)O` |
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| 90. |
Atoms in `P_4` molecule of white phosphorus are arranged regularly in the following way :A. At the corners of a cubeB. At the corners of an octahedronC. At the corners of a tetrahedronD. At the centre and corners of a tetrahedron |
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Answer» Correct Answer - C In `P_(4)` molecules, P atoms occupy corners of a tetrahedron. |
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| 91. |
Doping Si or Ge with As or P will produceA. p-type semiconductor Ge and n-type semiconductor SiB. n-type semiconductor Ge and p-type semiconductor SiC. n-type semiconductor Ge and n-type semiconductor SiD. p-type semiconductor Ge and p-type semiconductor Si. |
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Answer» Correct Answer - C Doping si or Ge(both with 4 valence electrons) with As or P (with 5 valence electrons) will produce n-type semiconductor in both cases. |
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| 92. |
Which of the following halides is the most acidic?A. `PCl_(3)`B. `SbCl_(3)`C. `BiCl_(3)`D. `C Cl_(4)` |
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Answer» Correct Answer - A `C Cl_(4)` cannot accept a lone pair of electron. As such it is not a Lewis acid. Acid strength of trichlorides is in the order `PCl_(3) gt AsCl_(3) gt SbCl_(3)` Thus `PCl_(3)` is more acidic than `SbCl_(3)`. |
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| 93. |
The most acidic of the following compounds isA. `P_(2)O_(3)`B. `Sb_(2)O_(3)`C. `B_(2)O_(3)`D. `As_(2)O_(3)` |
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Answer» Correct Answer - A Acidic given character of oxides decreases down the group. Thus `P_(2)O_(3)` is most acidic. |
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| 94. |
Out of the following compounds the most acidic isA. `As_(2)O_(3)`B. `P_(2)O_(3)`C. `Sb_(2)O_(3)`D. `Bi_(2)O_(3)` |
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Answer» Correct Answer - B `P_(2)O_(3)` is most acidic because electronegativity decrease in the order P gt As gtSb gtBi. |
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| 95. |
Which one of the followig elements occur free in nature?A. NB. PC. AsD. Sb |
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Answer» Correct Answer - A In group 14, only N occure free in nature as `N_(2)` |
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| 96. |
Which of the following flourides does not exist?A. `NF_(5)`B. `PF_(5)`C. `AsF_(5)`D. `SbF_(3)` |
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Answer» Correct Answer - A Nitrogen cannot show a covalency of five hence `NF_(5)` does not exist.] |
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| 97. |
Which of the following trihalides is not hydrolysedA. `PF_(3)`B. `PCl_(3)`C. `AsCl_(3)`D. `SbCl_(3)` |
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Answer» Correct Answer - A `PF_(3)` does not undergoes hydrolysis because P-F bond is more stronger than P-O bond |
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| 98. |
Amongst the trihalides of nitrogen, which one has the highest dipole momentA. `NF_(3)`B. `NCl_(3)`C. `NI_(3)`D. `NBr_(3)` |
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Answer» Correct Answer - B Nitrogen is more electronegative than I, hence, the dipole moment of bond atoms adds to that of the lone pair resulting in increases in the polarity. |
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| 99. |
Reaction of `HNO_3` with I, S, P and c gives respectivelyA. `HIO_(3),H_(2)SO_(4),H_(3)PO_(4)` and `CO_(2)`B. `HIO_(3),H_(2)SO_(4),H_(3)PO_(4)` and `CO_(2)`C. `HIO_(2),H_(2)SO_(4),H_(3)PO_(4)` and COD. `I_(2)O_(5),SO_(2),P_(2)O_(5)` and `CO_(2)` |
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Answer» Correct Answer - A `I_(2)+10HNO_(3) overset(Delta)to2HIO_(3)+10NO_(2)+4H_(2)O` `S+6HNO_(3) overset(Delta)to H_(2)SO_(4) +6NO_(2)+2H_(2)O` `P_(4)+20HNO_(3) overset(Delta)to4H_(3)PO_(4) +20NO_(2)+4H_(2)O` `C+4HNO_(3) overset(Delta)toCO_(2)+4NO_(2)+2H_(2)O` |
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| 100. |
Phosphorus has the oxidation state `+3` inA. Phosphorus acidB. Hypophosphors acidC. Orthphoshoric acidD. Pyrohosphoric acid |
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Answer» Correct Answer - A `overset(+1)(H)_(3) overset(x)(P) overset(-2)(O)_(3)` `+1 xx 3 +x -2 xx 3=0` or `x+3-6 =0` or `x=+3` |
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