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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. |
A mixture of 0.02 mole of `KBrO_(3)` and `0.001` mole of `KBr` was treated with excess of KI and acidified. The volume of 0.01M `Na_(2)S_(2)O_(3)` solution required to consume the liberated iodine will be :A. 1000mLB. 1200mLC. 1500mLD. 800mL |
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Answer» Correct Answer - b |
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| 52. |
A solution of `Na_(2)S_(2)O_(3)` is standardizes iodometrically against 0.1262 g of `KBrO_(3)` where `BrO_(3)^(-)` changes to `Br^(-)` . This process requires 45mL of the `Na_(2)S_(2)O_(3)` solution. What is the molariy fo the `Na_(2)S_(2)O_(3)`? [M.W. of `KBrO_(3)`=167]A. 0.2B. 0.1C. 0.05D. 0.01 |
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Answer» Correct Answer - b |
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| 53. |
For the reaction `3Br_(2)+6OH^(ө)-ltBr^(ө)+BrO_(3)^(ө)+3H_(2)O` Equivalent weight of `Br_(2)` (molecular weitht M) isA. `(M)/(2)`B. `(M)/(10)`C. `((M)/(2)+(M)/(10))`D. `((M)/(6))` |
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Answer» Correct Answer - C `Br_(2)` disproprtions (simultaneous oxidation and reduction), its equivalent weight is the sum of equivalent weights of the two half reactions. `2e^(-)+Br_(2)rarr2Br^(ө)(x=2)` (reduction) `Br_(2)rarr2BrO_(3)^(ө)+10e^(-)(x=10)("oxidation")` `2x=0, 2x-12= -2` `2x=10` `:. Ew=(M)/(2)+(M)/(10)` |
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| 54. |
Which of the following species does not show disproportionation reaction?A. `ClO_4^(-)`B. `ClO_(3)^(-)`C. `ClO_2^(-)`D. `ClO^(-)` |
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Answer» Correct Answer - A In a disproportionation reaction, an element in one oxidation state is simultaneously oxidized as well as reduced. This is possible provided the element (capable of existing in at least three oxidation states) is present in the intermediate oxidation state in the reacting species. Among the oxo-anions of chlorine listed above, `ClI_(4)^(-)` does not disproportionate because in this oxoanion, ` Cl` is present in its highest oxidation state (+7). Thus it can be reduced only but cannot be oxidized. The disproportionation reactions for the other three oxoanions of chlorine are as follows : `4overset(+5)(Cl)O_(3)^(-) rarr overset(-1)(Cl^(-))+3overset(+7)(Cl)O_(4)^(-)` `6overset(+3)(Cl)O_(2)^(-) rarr 2overset(-1)(Cl^(-))+4overset(+5)(Cl)O_(3)^(-)` `3overset(+3)(Cl)O^(-) rarr 2overset(-1)(Cl^(-))+overset(+5)(Cl)O_(3)^(-)` |
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| 55. |
Molecular weight of `KBrO_(3)` is M. What is its equivalent weight, if the reaction is : `BrO_(3)^(-)rarrBr^(-)" (acidic medium)"`A. MB. M/4C. M/6D. 6M |
| Answer» Correct Answer - C | |
| 56. |
In the reaction, `I_(2)+2S_(2)O_(3)^(2-) rarr 2I^(-)+S_(4)O_(6)^(2-)`. Equivalent wieght of iodine will be equal toA. its molecular weightB. `1//2` of its molecular weightC. `1//4` of its molecular weightD. twice of its molecular weight |
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Answer» Correct Answer - B `1_(2)^(0)overset(+2e^(-))rarr2I^(-)` `n=2` |
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| 57. |
In the reaction, `I_(2)+2S_(2)O_(3)^(2-) rarr 2I^(-)+S_(4)O_(6)^(2-)`. Equivalent wieght of iodine will be equal toA. `I_(2)` is reducing agent.B. `I_(2)` is oxidising agent and `S_(2)O_(3)^(2-)` is reducing agentC. `S_(2)O_(3)^(2-)` is oxidising agent.D. `I_(2)` is reducing agent and `S_(2)O_(3)^(2-)` is oxidising agent. |
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Answer» Correct Answer - B `overset(0)I_(2) rarr overset(-2)(2I^(-))` `I_(2)` undergoes reduction hence acts as oxidising agent. `S_(2)^(+2)O_(3)^(2-)rarrS_(4)^(+2.5)O_(6)^(2-)` It undergoes oxidation hence acts as a reducing agent. |
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| 58. |
In the reaction, `I_(2)+2S_(2)O_(3)^(2-) rarr 2I^(-)+S_(4)O_(6)^(2-)`. Equivalent wieght of iodine will be equal toA. Its Mol. wt.B. Mol. wt./2C. Mol. wt./4D. None of these |
| Answer» Correct Answer - B | |
| 59. |
In the reaction `VO+Fe_(2)O_(3) rarr FeO+V_(2)O_(5)`, the eq.wt. of `V_(2)O_(5)` is equal to itsA. Mol. wt.B. Mol.wt./8C. Mol.wt./6D. None of these |
| Answer» Correct Answer - C | |
| 60. |
In which species does sulphur have the lowest oxidation state?A. `SCl_(2)`B. `OSF_(2)`C. `H_(2)SO_(3)`D. `SF_(6)` |
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Answer» Correct Answer - a |
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| 61. |
What is the average oxidation state of copper in the superconductor `Yba_(2)Cu_(3)O_(7)` ?A. `+2`B. `+2.33`C. `+2.67`D. `+3` |
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Answer» Correct Answer - b |
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| 62. |
A sample containing 1 mol `KHC_(2)O_(4).H_(2)C_(2)O_(4)` is titrated with different reagent. Select correct statement.A. 1 mol of KOH are usedB. `(3)/(2)` moles of `Ba(OH)_(2)` are usedC. `(4)/(5)` mol of `KMnO_(4)` are used in alkaline mediumD. `2/(3)` mol of `K_(2)Cr_(2)O_(7)` are used in acidic medium |
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Answer» Correct Answer - b,d |
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| 63. |
A 0.200g sample of benzonic acid, `C_(6)H_(5)COOH`, is titrated with a 0.120 M `Ba(OH)_(2)` solution. What volume of the `Ba(OH)_(2) ` solution is required to reach the equivalance point? `{:("Substance","Molar mass"),(C_(6)H_(5)COOH,"122.1 g "mol^(-1)):}`A. 6.82mLB. 13.6mLC. 17.6mLD. 35.6mL |
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Answer» Correct Answer - a |
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| 64. |
Find out the oxidation number of chlorine in the following compounds and arrange them in increasing order of oxidation number of chlorine. `NaClO_(4), NaClO_(3), NaClO, KClO_(2), Cl_(2)O_(7), ClO_(3), Cl_(2)O, NaCl, Cl_(2), ClO_(2)`. Which oxidation state is not present in any of the above compounds?` |
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Answer» Suppose that the oxidation number of chlorine in these compounds be x O.N. of Cl in `NaClO_(4)" ":." "+1+x+4(-=2)=0" or",x=+7` O.N of Cl in `NaClO_(3)" ":." "+1+x+3(-2)=0" or", x=+5` O.N. of Cl in `NaClO" ":." "+1+x+1(-2)=0" or",x=+1` O.n of Cl in `KClO_(2)" " ,." "+1+x+2(-2)=0" or",x=+3` O.N. of Cl in `Cl_(2)O_(7)" ":." "+2x+7(-2)=0" or",x=+7` O.N. of Cl in `ClO_(3)" ":." "x+3(-2)=0" or",x=+1` O.N. of Cl in `NaCl" ":." "+1+x=0" or",x=-1` O.N. of Cl in `Cl_(2)" ":." "2x=0" or",x=0` O.N. of Cl in `ClO_(2)" ":." "x+2(-2)=0" or", x=+4` None of these compounds have an oxidation number of +2. Increasing order of oxidation number of chlorine is : `-1,0,+1,+3,+4,+5,+6,+7` Therefore, the increasing order of oxidation number of Cl in compounds is `NaCl lt Cl_(2) lt NaClO lt KClO_(2) lt ClO_(2) lt NaClO_(3) lt ClO_(3) lt Cl_(2)O_(7)` |
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| 65. |
Write the half reactions for the following redox reactions: (a) `2fe_((aq.))^(3+)+2I_((aq.))^(-)rarr2Fe_((aq.))^(2+)+I_(2(aq.))` (b) `Zn_((s))+2H_((aq.))^(+)rarrZn_((aq.))^(2+)+H_(2(g))` (c ) `Al_((s))+3Ag_((aq.))^(3+)rarrAl_((aq))^(3+)+3Ag_((s))` |
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Answer» (a) `Fe^(3+)+erarrFe^(2+)`, `I^(-)rarr1//2I_(2)+e` (b) `Zn rarr Zn^(2+)+2e`, `H^(+) + e rarr 1//2H_(2)` ( c) `Al rarrAl^(3+) + 3e` `Ag^(+) + e rarr Ag` |
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| 66. |
When zinc is added to `CuSO_(4)` solution, copper is precipitated. It is because ofA. Reduction of ZnB. Reduction of `Cu^(2+)`C. Hydrolysis of `CuSO_(4)`D. Reduction of `SO_(4)^(2-)` |
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Answer» Correct Answer - B `Cu^(2+)+2e^(-)rarr Cu(s)` |
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| 67. |
1.245 g of `CuSO_(4). xH_(2)O` was dissolved in water and `H_(2)S` gas was passed through it will till CuS was completely precipitated . The `H_(2)SO_(4)` produced in the filtrate required 100 ml of 0.1 M NaOH solution . Calculate x (approximately)A. 5B. 6C. 7D. 8 |
| Answer» Correct Answer - C | |
| 68. |
`Zn+H_(2)SO_(4)rarrZnSO_(4)+H_(2)` Zn undergoes -A. ReductionB. OxidationC. Both oxidation and reductionD. None of these |
| Answer» Correct Answer - B | |
| 69. |
Which of the following statement is true regarding the following balanced half-reaction? `CN^(-) rarr CNO^(-)`A. Carbon is losing two electrons per atomB. Oxidation number of carbon increase from `+1 " to " +3`C. Oxidation number of nitrogen remains constantD. Both (a) and (c) |
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Answer» Correct Answer - D In the given redox reaction, `C^(-) -= N rarr O^(-) - C -= N` Oxidation number of nitrogen is remaining unchanged at `-3`. Oxidation number of carbon is increasing from `+2 " to " +4`. Hence (a) and (c) are the only correct response. therefore, option (d) is correct. |
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| 70. |
which of the following represent redox reactions? I. `Cr_(2)O_(7)^(2-)+2overset(ө)OHrarr2CrO_(4)^(2-)+H_(2)O` II. `Zn+CuSO_(4)rarrZnSO_(4)+Cu` III. `MnO_(4)^(ө)+3Mn^(2+)+4overset(ө)OHrarr5MnO_(2)+2H_(2)O` IV. `2Cu^(o+)rarrCu+Cu^(2+)`A. `I,II`B. `I,III`C. `III,IV`D. `II,III,IV` |
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Answer» Correct Answer - D `II, III and IV` are redox reactions. |
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| 71. |
What sort of informations can you draw from the following reaction? `(CN)_(2)(g) + 2overset(Θ)(OH)(aq) rarrCN^(Θ)(aq)+CNO^(Θ)(aq) + H_(2)O(l)` |
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Answer» The oxidation number of carbon in `(CN)^(2) , CN^(-)` and `CNO^(-)` are +3, +2 and +4 respectively . These are obtained as shown below : Let the oxidation number of C be x . `(CN)_(2)` `2(x - 3) = 0` `therefore x = 3` `CN^(-)` `x - 3 = -1` `therefore x = 2 ` `CNO^(-)` `x - 3 -2 = -1` `therefore x = 4` The oxidation number of carbon in the various species is : `(overset(+3)(C) N)_(2 (g)) + 2OH_((aq))^(-) to overset(+2)(C) N_((aq))^(-) + overset(+4)(C)NO_((aq))^(-) + H_(2)O_((l))` It can be easily observed that the same compound is being reduced and oxidised simultaneously in the given equation. Reactions in which the same compound is reduced and oxidised is known as disproportionation reactions. Thus, it can be said that the alkaline decomposition of cyanogen is an example of disproportionation reaction. |
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| 72. |
Which of the following are examples of disproportionation reaction?A. `HgO toHg+O_(2)`B. `KClO_(3) to KCl+O_(2)`C. `KClO_(3) to KVlO_(4)+KCl`D. `Cl_(2)+OH^(-) to ClO^(-)+Cl^(-)+H_(2)O` |
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Answer» Correct Answer - c,d |
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| 73. |
Which of the following are examples of disproportionation reactions? a. `Ag(NH_(3))_(2)^(o+)+2H^(o+)rarrAg^(o+)+2overset(o+)NH_(4)` b. `Cl_(2)+2overset(ө)OHrarrClO^(ө)+Cl^(ө)+H_(2)O` c. `CaCO_(3)rarrCaO+CO_(2)` d. `2HgOrarr2Hg+O_(2)` e. `Cu_(2)O+2H^(o+)rarrCu+Cu^(2+)+H_(2)O` f. `CuS+O_(2)rarrCu+SO_(2)` g. `2HCuCl_(2)+"dilute with" H_(2)OrarrCu+Cu^(2+)+4Cl^(ө)+2H^(o+)` h. `2H_(2)O_(2)rarr2H_(2)O+O_(2)` |
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Answer» `(overset(+1)Agoverset(-3)NH_(3))_(2)^(+)+2H^(+)rarroverset(+1)Ag+(23overset(-3)NH_(4))^(+)` Since there is no change in O.N of the lements ivolved in the reaction there is neither oxidation nor reduction therefore , this is not a disportionation reaction `overset(0)CI_(2)+2OH^(-)rarr overset(-1)CI^(-)+overset(+1)(CIO)^(-)+H_(2)O` In this reaction , `CI_(2)` is reduced to `CI^(-)` ion and is also oxidised to `CIO^(-)` ion.This is na example of disproportionation reaction. |
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| 74. |
Which of the following examples does not represent disproportionation ?A. `MnO_(2)+4HClrarrMnCl_(2)+Cl_(2)+2H_(2)O`B. `2H_(2)O_(2)rarr2H_(2)O+O_(2)`C. `4KClO_(3)rarr3KClO_(4)+KCl`D. `3Cl_(2)+6NaOHrarr5NaCl+NaClO_(3)+3H_(2)O` |
| Answer» Correct Answer - A | |
| 75. |
Which of the following change represents a disproportionation reaction (s) :A. `Cl_(2)+2OH^(-)rarrClO^(-)+Cl^(-)+H_(2)O`B. `Cu_(2)O+2H^(+)rarrCu+Cu^(2+)+H_(2)O`C. `2HCuCl_(2)overset("dilution with")underset("Water")rarrCu+Cu^(2+)+4Cl^(-)+2H^(+)`D. All of the above |
| Answer» Correct Answer - D | |
| 76. |
The decomposition of `KClO_(3)` to KCl and `O_(2)` on heating is an example of :A. Intermolecular redox changeB. Intermolecular redox changeC. Disproportionation or auto redox changeD. None |
| Answer» Correct Answer - B | |
| 77. |
The valancy of carbons is generally `4`, but its oxidation state may be `-4, -2, 0, +2, -1`, etc. In the compounds containing `C, H`, and `O`, the oxidation number of `C` is calculated as Oxidation number of `C= (2n_(O)-n_(H))/(n_(C ))` Where `n_(O), n_(H)` and `n_(C )` are the numbers of oxygen, hydrogen, and carbons, atoms, respectively. In which of the following compounds is the oxidation state of carbon is zero?A. `CH_(4)`B. `CH_(3)OH`C. `HCOOH`D. `C_(6)H_(12)O_(6)` |
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Answer» Correct Answer - D a. `overset(-4+1xx4)(CH_(4))` oxidation state of `C=4-4` b. `CH_(3)OH: x+4-2=0 impliesx= -2` c. `HCOOH:x+2-4 =0implies x=2` d. `C_(6)H_(12)O_(6): 6x+12-12=0 implies x=0`. |
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| 78. |
The valancy of carbons is generally `4`, but its oxidation state may be `-4, -2, 0, +2, -1`, etc. In the compounds containing `C, H`, and `O`, the oxidation number of `C` is calculated as Oxidation number of `C= (2n_(O)-n_(H))/(n_(C ))` Where `n_(O), n_(H)` and `n_(C )` are the numbers of oxygen, hydrogen, and carbons, atoms, respectively. In which of the following compounds is the valency of `C` two?A. KetenesB. AlkenesC. AllenesD. Carbenes |
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Answer» Correct Answer - D a. `H_(2)C=C=O`(Ketenes)(Valency of `C=4`) b. `R_(2)(C )=CR_(2)`(alkenes) (Valency of `C=4`) c. `H_(2)C=C=CH_(2)`(Allenes) (Valency of `C=4)` d. `:CH_(2)` (Carbenes) (Valency of `C=2`) |
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| 79. |
The valancy of carbons is generally `4`, but its oxidation state may be `-4, -2, 0, +2, -1`, etc. In the compounds containing `C, H`, and `O`, the oxidation number of `C` is calculated as Oxidation number of `C= (2n_(O)-n_(H))/(n_(C ))` Where `n_(O), n_(H)` and `n_(C )` are the numbers of oxygen, hydrogen, and carbons, atoms, respectively. Teh oxidation of `C` in diamonds isA. `0`B. `+1`C. `-1`D. `+2` |
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Answer» Correct Answer - A Carbon in diamond is in elemental state, so the oxidation state of `C` in diamond is zero. |
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| 80. |
A cell is set up between copper and silver electrodes as follows: `Cu(s)I Cu^(2+)(aq)II Ag^+(aq)Iag(S)` If the two half cells work under standard conditions, calculate the EMF of the cell `(Given E^(@)_(Cu^(2+)//Cu) =+0.34 V,E^(@)_(Ag^(+)//Ag)" " =+0.80 V)` |
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Answer» From the `E^(@)` values it is clear that copper acts as the anode silver as the cathode. `E^(@)_(cell)=E^(@)_(cathode-E^(@))_(Enode)=0.80-(0.34)=+0.46 "volt"` |
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| 81. |
Oxidation number if iodine in `IO_(3)^(-), IO_(4)^(-),KI and I_(2)` respectively areA. `-2, -5, -1, 0`B. `+5, +7, -1, 0`C. `+2, +5, +1, 0`D. `-1, +1, 0, +1` |
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Answer» Correct Answer - B `IO_(3)^(-)rarr x+3(-2)=-1rArr x=+5` `IO_(4)^(-)x+4(-2)=-1 rArr x = +7` `KI rarr +1+x=0 rArr x = - 1` `I_(2)rarr0 rArr x=0` |
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| 82. |
Balance the chemical equation by the oxidation number method. (i) `CuO + NH_(3) to Cu + N_(2) + H_(2)O` |
| Answer» `3Cu+ 2NH_(3) to 3Cu+N_(2) + 3H_(2)O` | |
| 83. |
What is the oxidation numbr of iodine in each of the following compounds: `IF_(7), IF_(5),KI,I_(2), ICI,HIO_(4)`? |
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Answer» Correct Answer - A `+7, +5,-1,0-+1+7` |
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| 84. |
Balance the following equations by ion electron method: a. `CuO + NH_(3) rarr Cu+H_(2)O+N_(2)` b. `HNO_(3)+I_(2) rarr HIO_(3) + NO_(2) + H_(2)O` |
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Answer» Correct Answer - A a. `3CuO+2NH_(3)rarr3Cu+N_(2)+3H_(2)O` b. `10 NO_(3)^(ө)+10H^(o+)+I_(2)rarr2IO_(3)^(ө)+2H^(o+)+2H^(o+)+10NO_(2)+4H_(2)O` or `10 HNO_(3)+I_(2)rarr2HIO_(3)+10NO_(2)+4H_(2)` |
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| 85. |
Number of `K^(+)` ions present in one litre of `M//5KMnO_(4)` solution are:A. `10xx10^(24)`B. `1.024xx10^(23)`C. `6.02xx10^(23)`D. `3.01xx10^(24)` |
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Answer» Correct Answer - B Milli-mole of `KMnO_(4)=1000xx(1)/(5)=200` `:. 1 "mole of" KMnO_(4)` has `N_(A)K^(+)` ions `:. 0.2 "mole of"KMnO_(4)` has `0.2xxN_(A)K^(+)"ions"` |
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| 86. |
The oxidation states of the most electronegative elements in the products of the reaction between `BaO_(2)` and `H_(2)SO_(4)` areA. `0` and `-1`B. `-1` and `-2`C. `-2` and `0`D. `-2` and `+1` |
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Answer» Correct Answer - B In `H_(2)O_(2)` oxygen shows `=-1` (peroxide) oxidation state and in `BaSO_(4)` oxygen shows `=-2` oxidation state. |
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| 87. |
The highest oxidation state of `Mn` is shown byA. `K_(2)MnO_(4)`B. `KMnO_(4)`C. `MnO_(2)`D. `Mn_(2)O_(2)` |
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Answer» Correct Answer - B `Mn` shows highest oxidation state in `overset(+7)(KMnO_(4))`. |
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| 88. |
Balance the chemical equation by the oxidation number method. (ix) `I_(2) + HNO_(3) to HIO_(3) + NO_(2) + H_(2)O` |
| Answer» `I_(2) + 10HNO_(3) to 2HIO_(3) + 10NO_(2) + 4H_(2)O` | |
| 89. |
What weight of `HNO_(3)` is needed to convert `5g` of iodine into iodic acid according to the reaction, `I_(2)+HNO_(3)rarrHIO_(3)+NO_(2)+H_(2)O`A. `12.4 g`B. `24.8 g`C. `0.248 g`D. `49.6 g` |
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Answer» Correct Answer - A `{:(1e,+,N^(5+),rarr,N^(4+),),(,,I_(2)^(0),rarr,2I^(5+),+10e),(,,,,,):}` Meq. Of `HNO_(3)=` Meg. Of `I_(2)` `(w)/(63//1)xx1000xx=(5)/(254//10)xx1000` `w=12.4g` |
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| 90. |
Which will be the value of x, y and z in the following equaton. `xI_(2)+yOH^(-)rarrIO_(3)^(-)+zI+3H_(2)O`A. `{:(x,y,z),(6,3,5):}`B. `{:(x,y,z),(3,2,3):}`C. `{:(x,y,z),(3,6,5):}`D. `{:(x,y,z),(3,3,3):}` |
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Answer» Correct Answer - C `I_(2)+OH^(-)rarr IO_(3)^(-)+I^(-)+H_(2)O` Oxidation half : `I_(2)+OH^(-)rarr IO_(3)^(-)+H_(2)O` Reduction half : `I_(2)rarr I^(-)` Oxidation half- Adding `OH^(-), I_(2)+12OH^(-)rarr 2IO_(3)^(-)+6H_(2)O` Adding electrons : `I_(2)+12OH^(-)rarr 2I_(3)^(-)+6H_(2)O+10e^(-)` Reduction half - `I_(2)+2e^(-)rarr 2I^(-)` Balancing `e^(-), I_(2)+12OH^(-)rarr 2IO_(3)^(-)+6H_(2)O+10e^(-)` `I_(2)+2e rarr 2I^(-)] xx 5` Adding both reactions `6I_(2)+12OH^(-)rarr 2IO_(3)^(-)+10I^(-)+6H_(2)O` Dividing by 2, `3I_(2)+6OH^(-)rarr IO_(3)^(-)+5I^(-)+3H_(2)O` |
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| 91. |
Which will be the value of x, y and z in the following equaton. `xI_(2)+yOH^(-)rarrIO_(3)^(-)+zI+3H_(2)O`A. `3, 5, 6`B. `5, 6, 3`C. `3, 6, 5`D. `6, 3, 5` |
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Answer» Correct Answer - C `{:(overset(0)I_(2)rarroverset(+5)(IO_(3))," ..................(i) Oxidation"),(overset(0)I_(1)rarroverset(-1)I^(-)," ..................(ii) Reduction"):}` Balancing atoms of iodine on both sides, we get, `" "I_(2)rarr2IO_(3)^(-)` `or "I_(2)+12OH^(-)rarr2IO_(3)^(-)+6H_(2)O` Blancing charge, `" "I_(2)+12OH^(-)rarr2IO_(3)^(-)+6H_(2)O+10e^(-)` `" "I_(2)rarr2I^(-)` `"and "(I_(2)+2e^(-)rarr2I^(-))xx5` `"adding "6I_(2)+12OH^(-)rarr2IO_(3)^(-)+10I^(-)+6H_(2)O` `"or, "3I_(2)+6OH^(-)rarrIO_(3)^(-)+5I^(-)+3H_(2)O` |
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| 92. |
The oxidation number of C in HCN and HNC respectively areA. `+2, +2`B. `+2,+4`C. `+4,+4`D. `-2,-2` |
| Answer» Correct Answer - A | |
| 93. |
In alkaline medium, `ClO_(2)` oxidises `H_(2)O_(2) "to" O_(2)` and is itself reduced to `Cl^(ө)`. How many moles of `H_(2)O_(2)` are oxidised by `1 "mol of " ClO_(2)` ?A. 1B. 1.5C. 2.5D. 3.5 |
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Answer» Correct Answer - c |
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| 94. |
How do the following ions undergo disproportionation `(i) CIO^(-), (ii)CIO_(2)^(-),(iii)CIO_(3)^(-)?` |
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Answer» `(i)CIO^(-) ("hypochlorite ion") 3overset(+1)CIO^(-)rarr2overset(-1)CI^(-)+overset(+5)CIO_(3)` `(ii) CIO_(2)^(-)("Chlorite ion") 3overset(+3)CIO_(2)rarroverset(-1)CI^(-)+2overset(+5)CIO_(3)` `(iii)CIO_(3) ("Chlorate ion") 4overset(+5)CIO_(3)rarroverset(-1)CI+3overset(+7)CIO_(4)` |
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| 95. |
Assertion : All halogens undergo disproportionation reaction in alkaline medium. Reason : All halogens exhibit variable oxidation states.A. If both assertion and reason are true and reason is the correct explanation of assertion.B. If both assertion and reason are true but reason is not the correct explanation of assertion.C. If assertion is true but reason is false.D. If both assertion and reason are false. |
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Answer» Correct Answer - D `Cl_(2),Br_(2)` and `I_(2)` undergo disproportionation reaction whereas fluorine does not undergo disproportionation being the most electronegative element. Fluorine cannot exhibit positive oxidation state and hence does not show disproportionation tendency. Fluorine can exhibit only - I oxidation state. |
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| 96. |
Find out the oxidation number of chlorine in the following compounds `NaCIO_(4),NaCIO_(3),NaCIO,KCIO_(2),CI_(2)O,NaCI,CI_(2)` |
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Answer» `NaCIO_(4): overset(+1)Naoverset(x)CIoverset(-2)O_(4) 1+x-8=0 or x=+7` `NaCIO_(3): overset(+1)Naoverset(x)CIoverset(-2)O_(3) 1+x-6=0 or x=+5` `NaCIO: overset(+1)Naoverset(x)CIoverset(-2)O 1+x-2=0 x=+1` `KCIO_(2): overset(+1)Naoverset(x)CIoverset(-2)O_(2) 1+x-4=0 x=+3` `CI_(2)O_(7): CI_(2)O_(7)^(-2) 2x-14=0 x=+7` `CIO_(3):overset(x)CI overset(3^(-2))` x-6=0 x=+6 `CI_(2)O: overset(x)CI_(2)overset(-2)O 2x-2=0 x=1` `NaCI: overset(+1)Naoverset(x)CI 1+x=0 x=-1` `CI_(2): overset(+0)CI_(2)x=0` |
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| 97. |
Which species are oxidised and reduced in the reaction? `FeC_(2)O_(4)+KMnO_(4)rarrFe^(2+)+CO_(2)+Mn^(2+)`A. Oxidised: `Fe, C`Reduced: `Mn`B. Oxidised: `Fe` Reduced: `Mn`C. Reduced: `Fe, Mn` Oxidised: `C`D. Reduced: `C` Oxidised: `Mn, Fe` |
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Answer» Correct Answer - A `Fe` and carbon in `FeC_(2)O_(4)` are oxidised `{:(Fe^(2+)rarrFe^(3+)+e,,,,),((C^(2+))_(2)rarr2C^(4+)+2e,,,,):}` `Mn` in `KMnO_(4)` is reduced. `5e+Mn^(7+)rarrMn^(2+)` |
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| 98. |
The equivalent weight of `FeC_(2)O_(4)` in the change `FeC_(2)O_(4)rarrFe^(3+)+CO_(2)` isA. `M//3`B. `M//6`C. `M//2`D. `M//1` |
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Answer» Correct Answer - A `{:(Fe^(2+)rarrFe^(3^(+))+e^(-),,,,),(C_(2)O_(4)^(2-)rarr2CO_(2)+2e^(-),,,,):}]n=3` Equivalent weight of `FeC_(2)O_(4)=(M)/(3)` |
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| 99. |
A `1 g` sample of `Fe_(2)O_(3)` solid of `55.2%` purity is dissolved in acid and reduced by heating the solution with zinc dust. The resultant solution is cooled and made upto `100 mL`. An aliquot of `25 mL` of this solution requires `17 mL` of `0.0167M` solution of an oxidant for titration. Calculate no.of electrons taken up by oxidant in the above titration. |
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Answer» Correct Answer - 6 |
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| 100. |
A sample consisting fo chocolate-brown powder of `PbO_(2)` is allowed to react with excess of KI and iodine liberated is reacted with `N_(2)H_(4)` in another container. The volume of `N_(2)` gas liberated from this second container at STP was measured out to be 1.135 litre. Find the volume (in L) of decimolar NaOH solution required to dissolved `PbO_(2)` completely and convert it to `Na_(2)PbO_(3)`. (Assume all reactions are 100% complete). |
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Answer» Correct Answer - 2 |
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