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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.
| 101. |
Which species is not known?A. `XeF_(6)`B. `XeF_(4)`C. `XeO_(3)`D. `KrF_(6)` |
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Answer» Correct Answer - d Except `Xe` florides i.e. `XeF_(2),XeF_(4),XeF_(6)` flrorides of `Kr` and `Rn` known as `KrF_(2),KrF_(4)` and `RnF_(2)` |
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| 102. |
The none-existent species isA. `XeF_(5)`B. `BrF_(5)`C. `SbF_(5)`D. `PF_(5)` |
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Answer» Correct Answer - a Coordination number of `Xe` can be `2,4,6` as it can have `2,4,` and `6` unpaired electrons only .Hence `XeF_(5)` is not known . |
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| 103. |
(a) Which form of sulphur shows paramagnetic behaviour ? (b) Compounds of fluorine and oxygen are called fluorides and not oxides. Explain. (c) Sulphur disappears when boiled with an aqueous solution of sodium sulphite. Why ? |
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Answer» (a) In vapour state, sulphur partly exists as `S_2` molecules and `S_2` molecule like `O_2` molecule has two unpaired electrons in the antibonding `pi^**-orbitals` and exhibits paramagnetic nature. (b) This is because of higher electronegativity of flurine than oxygen. In naming a compound, the electronegative element is taken first, thus, the compounds of fluorides and fluorine oxides. (c) Sulphur combines with sodium sulphite and forms sodium thiosulphate which is soluble in water and hence `S` disappears. |
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| 104. |
(a)What prompted Brithent in the disonvery of noble gas compounds? (b) The majurity of noble gas compound are these of xenon .Give reason (c ) No chemical compound of He in known why? |
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Answer» (a) Since `PtF_(2)` oxides `O_(2)` to `O_(2)`, Bartlent through that `PtF_(3)` should also oxides `Xe` to `Xe` because the ionisation undalpales of `O_(2)(1175 kJ mol^(-1)) `and `Xe (1170kJ mol^(-1))` atr quit comparable. (b) Except Rs, which is raductive , `Xe` has the inos ionsstion carbolpy among group `18` element and hence can be casily oxides by strong oxidising agents likes `F_(2) or O_(2)` .That is why majority of noble gas compound are that of semon. (c ) Helum does not from chemical compounds because (i) Electronic configuration of He is `1s^(2)` .The tempuring of electron cannot be done in the He and beat it cannotfrom chemical compound. (ii) Ionisetion codralpy of He is very high. |
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| 105. |
Which of the following is an explosive compound ?A. `XeO_(3)`B. `XeF_(2)`C. `XeOF_(2)`D. `XeOF_(4)` |
| Answer» Correct Answer - a | |
| 106. |
The idea which prompted bartlett to prepare first ever compound of noble gas wasA. high bond energy of `Xe-F`B. low bond energy of `F-F` in `F_(2)`C. ionisation energies of `O_(2)` and xenon were almost similarD. none of the above |
| Answer» Correct Answer - c | |
| 107. |
Which noble gas has higher and least polarisability respectively ?A. He,XeB. Ne,KrC. Kr,NeD. Xe,He |
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Answer» Correct Answer - d `Xe` due to the hightest polarisability and He has least polarisability due to the largest and smallest size of `Xe` and `He` respectively. |
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| 108. |
Concentrated nitric acid can be stored in aluminium container. Give reason. |
| Answer» Aluminium is rendered passive by conc. `HNO_3` due to formation of an oxide layer on its surface. This film does not allow any further reaction between `HNO_3` and `Al` and hence conc. `HNO_3` can be stored in aluminium container. | |
| 109. |
Noble gases do not accur in …..A. natureB. oresC. atmosphereD. sea water |
| Answer» Correct Answer - d | |
| 110. |
The gas which is filed in tungstoen lamp is ________. |
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Answer» Correct Answer - Hellium Hellium |
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| 111. |
`C_(p)//C_(v)`, ratio for noble gases is ________. |
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Answer» Correct Answer - `1.66` `1.66` |
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| 112. |
Helium gives a characteristic spectrum withA. orange and red linesB. orange linesC. yellow lineD. green line |
| Answer» Correct Answer - c | |
| 113. |
Compounds formed when the noble gases get entrapped in the cavities of crystal lattices of certain oreganic and inorganic compounds are known asA. interstitial compoundsB. ClathratesC. HydratesD. Picrates |
| Answer» Correct Answer - b | |
| 114. |
An orange solid `(A)` on heating gave a green residue `(B)`, colourless gas `( C)` and water vapour. The dry gas `( C)` on passing over heated magnesium gave a white solid `(D).(D)` on reaction with water have a gas `( E)` which formed dense white fumes with `HCl`. Indentify `(A)` to `( E)` and give the reactions. |
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Answer» `underset ("Orange solid") ((A)) overset (Delta) rarr underset ("Green resi due")((B)) + underset ("Colourless gas")((C)) + H_2 O` `(C) + Mg rarr underset ("White gas solid") ((D)) overset (H_2 O)rarr (E) overset (HCl)rarr` Dense white fumes. Since `( E)` forms dense white fumes with `HCl, (E)` must be ammonia, `NH_3`. `NH_3 + HCl rarr NH_4 Cl` (Dense white forms) `NH_3` is formed by hydrolysis of solid `(D)` hence, `(D)` is `Mg_3 N_2`, magnesium nitride. `underset((D)) (Mg_3 N_2) + 6 H_2 O rarr 3 Mg (OH)_2 + underset ((E)) (2 NH_3)` Formation of `(D)` indicates that gas `( C)` is `N_2`. Thus `(A)` is ammonium dichromate. `underset((A))underset("Orange solid")((NH_(4))_(2)Cr_(2)O_(7))overset(Delta)tounderset((B))underset("Green solid")(Cr_(2)O_(3))+underset((C))underset("Colourless gas")(N_(2))+4H_(2)O` Hence `(A) is (NH_4)_Cr_2 O_7, (B) is Vr_2 O_3, ( C) is N_2, (D) is Mg_3 N_2 and ( E) is NH_3`. |
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| 115. |
An aqueous of a gas `(X)` shows the following reactions : (a) It turns red litmus blue. (b) When added in excess to a copper sulphate solution, a deep blue coloured solution is obtained. ( c) On addition to `FeCl_3` solution, a brownish precipitate is formed, which is solution in `HNO_3`. Identify `(X)` and give an explanation for step `(a),(b)` and `( c)`. |
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Answer» The gas `(X)` is ammonia, `NH_3`. (a) Aqueous solution of `NH_3` is `NH_4 OH`, which is basic and hence truns red litmus blue. (b) `CuSO_4 + underset (Excess) (4NH_4 OH) rarr underset ("Tetraamminecopper (II) sulphate")([Cu(NH_3)_4]^(2+) SO_4^(2-)) + 4 H_2 O` `[Cu(NH_3)_4] SO_4` is deep blue in colour and is soluble in water, hence deep blue coloured solution is formed. ( c) `FeCl_3 + 3NH_4OH rarr underset ("Brownish ppt.") (Fe(OH)_3 darr) + 3 NH_4 Cl` `Fe(OH)_3+ 3HNO_3 rarr underset ("Solution") (Fe(NO_3)_3) + 3 H_2 O` On addition of `NH_4OH` to `FeCl_3` solution, brown ppt. of ferric hydroxide, `Fe(OH)_3` is formed. `Fe(OH)_3` dissolves in `HNO_3` due to formation of ferrcnitrate, `Fe(NO_3)_3`. |
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| 116. |
A colourless inorganic salt `(A)` decomposes completely at about `250^@ C` to give only two products `(B)` and `( C)`, leaving no residue. The oxide `( C)` is a liquid at room temperature and neutral to litmus paper while the gas `(B)` is a neutral oxide. White phosphorous burns in excess of `(B)` to produce a strong white dehydrating agent. Write balanced equations for the reactions involved in this process. |
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Answer» Given, `underset (colourl ess)((A)) overset (250^@ C)rarr (B)_((g)) + underset (Ox ide)((C)_((1)))` inorganic compound Liquid `( C)` is neutral oxide at room temperature and neutral to litmus paper. Gas `(B)` is neutral oxide. `underset (Express) ((B)) + underset (White) (P_4) rarr` strong white dehydrating agent. Both `(B)` and `( C)` are neutral oxides, `(B)` helps in combustion of white phosphorous, hence `(B)` can be nitrons oxide, `N_2 O. ( C)` is liquid at room temperature, hence it can be `H_2 O`. `underset ((A)) (NH_4 NO_3) rarr underset ((B)) (N_2 O) + underset ((C))(2 H_2 O)` `10 N_2 O + P_4O_10 + 10 N_2` `P_4 O_10` is strong white dehydrating agent. `(A)` is ammonium nitrate, `NH_4 NO_3, (B)` nitrous oxides, `N_2 O( C)` is water, `H_2 O`. |
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| 117. |
Which one of the following is used for drying of ammonia ?A. `conc. H_2 SO_4`B. `CaO`C. `P_2 O_5`D. Anhydrous `CaCl_2` |
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Answer» Correct Answer - B Other reacts with `NH_3`, hence cannot be used. |
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| 118. |
Silver chloride dissolves in excess of `NH_4OH`. The cation present in solution is.A. `[Ag(NH_3)]^(oplus)`B. `[Ag(NH_3)_4]^(oplus)`C. `[Ag(NH_3)_2]^(oplus)`D. `[Ag(NH_3)_6]^(oplus)` |
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Answer» Correct Answer - C `AgCl + underset ((Express)) (2 NH_4 OH) rarr [Ag(NH_3)_2]^(oplus) Cl^(Ө) + 2 H_2 O`. |
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| 119. |
What are the products formed in the reaction of xenon hexafluoride with silicon dioxide?A. `XeSiO_(4) + HF`B. `XeF_(2) + SiF_(4)`C. `XeOF_(4) + SiF_(4)`D. `XeO_(3) + SiF_(2)` |
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Answer» Correct Answer - c `2XeF_(6) + SiO_(2) to 2XeOf_(4) + SiF_(4)` |
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| 120. |
Who observed helium first on the earth?A. Lothar meyerB. RamsayC. SheeleD. Rutherford |
| Answer» Correct Answer - b | |
| 121. |
_______is used as anaeshetic due to the formation of aquenous clatherates in physiologically strategic sports |
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Answer» Correct Answer - Xemon Xemon |
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| 122. |
The noble gas which shown abnormal behaviour in liquid state and behaves as a super fluid is ____. |
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Answer» Correct Answer - Hellium Hellium |
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| 123. |
Give the structural formula for the following : (i) Phosphorous acid, `H_3 PO_3` (ii) Pyrophosphoric acid, `H_4 P_2 O_7`. |
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Answer» (i) `underset((H_(3)PO_(3)))(HO-overset(O)overset(||)underset(H)underset(|)(P)-OH)` `(ii) underset((H_(4)P_(2)O_(7)))(OH-overset(P)overset(||)underset(OH)underset(|)(P)-O-overset(P)overset(||)underset(OH)underset(|)(P)-OH)` |
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| 124. |
(a) What is the role of phosphorous pentoxide in the preparation of `N_2 O_5` ? (b) Phosphine is prepared in an inert atmosphere of `CO_2`. Why ? ( c) Red phosphorous is used for making matches. Why ? |
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Answer» (a) `P_4O_10` acts as strong dehydrating agent. It removes water molecules from nitric acid, `HNO_3` to form `N_2 O_5`. `P_4 O_10 + 12 HNO_3 rarr 4 H_3 PO_4 + 6 N_2 O_5`. (b) Phosphine, being inflammable, burns in air. It is therefore prepared in an inert atmosphere. ( c) Red phosphorous is non-poisonous and has a high ignition point and hence red phosphorous is used for making matches. |
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| 125. |
(a) Why elemental phosphorous does not exist as `P_2` like `N_2` ? (b) `NCl_3` gets easily hydrolysed, while `NF_3` does not. Why ? |
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Answer» (a) Nitrogen due to its small size has a tendency to form multiple bond and thus exists as diatomic molecule. Phosphorous, on the other hand, has comparatively large size, therefore, extent of overlap of `(3p - 3p)` which can result in `pi-bond` formation is less, and phosphorous has no tendency to form multiple bond with itself. Hence phosphours does not exist as `P_2` molecule. (b) In `NCl_3, N` is more electronegative than `Cl`, hence `N` has `delta -` charge and `Cl` has `delta +` charge, moreover due to presence of vacant d-orbital on `Cl`, it accepts a pair of electron from `O` atom of `H_2 O` molecule. Thus hydrolysis is possible. On the other hand, in `NF_3` due to high `N-F` bond strength, `NF_3` molecule is inert and does not undergo hydrolysis. |
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| 126. |
Arrange the following as stated : Increasing order of the extent of hydrolysis : `C Cl_4, MgCl_2, AlCl_3, PCl_3, PCl_5, SiCl_4`. |
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Answer» `C Cl_4 lt MgCl_2 lt AlCl_3 lt PCl_5 lt SiCl_4` Increasing order of the extent of hydrolysis. `C Cl_4` does not get hydrolysed because carbon does not have vacant d-orbitals, so water cannot donate lone pair of electrons to start the reaction. |
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| 127. |
How many bridging oxygen atom are present in `P_4 O_10` ? |
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Answer» Correct Answer - `(1)` Bridging `O-atoms` in `P_4 O_10 = 6`. |
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| 128. |
Among the following , the number of compounds that can react with `PCl_5` to give `POCl_3` is. `O_2,CO_2,SO_2,H_2 O,H_2 SO_4,P_4 O_10`. |
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Answer» Correct Answer - `(4)` (i) `PCl_5 + O_2 rarr "No reaction"` (ii) `PCl_5 + CO_2 rarr "No reaction"` (iii) `6 PCl_5 + P_4 O_10 rarr 10 POCl_3` (iv) With limited amount of `H_2 O , PCl_5` gives `POCl_3` but with excess of water it does not give `POCl_3` but gives `H_3 PO_4`. (a) `PCl_5 + H_2 O ("limited") rarr POCl_3 + 2 HCl` (b) `PCl_5 + 4 H_2 O ("excess") rarr H_3 PO_4 + 5 HCl` (v) `PCl_5 + SO_2 rarr SOCl_2 ("Thionyl chloride") + POCl_3` (vi) `2 PCl_5 + H_2 SO_4 rarr underset (("Sulphuryl chloride")) (SO_2 Cl_2) + 2 POCl_3 + 2 HCl`. |
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| 129. |
Xe is the most reactive noble gas |
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Answer» Correct Answer - T 1 |
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| 130. |
What is the total number of unpaired eletrons in inert gas ? |
| Answer» General electronic configuration of noble gases is `ns^(2)np^(6)`. Hence, all the electrons are paired up, and number of unpaired electron present is zero. | |
| 131. |
Which one of the following statement is not correct?A. a.Ar is used in electric bulbB. b.Kr is obtained during redioactive decayC. c.Boiling point of helium to the lowest among all noble gasesD. d.`Xe` forms `XeOF_(4)` |
| Answer» Correct Answer - b | |
| 132. |
Major credit for the discovery of noble gases is given toA. CavendishB. RamsayC. RayleighD. None of these |
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Answer» Correct Answer - b Ramsay discovered many `(Kr, Xe,Ne)` of the noble gases. |
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| 133. |
He is an inert gas |
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Answer» Correct Answer - T 1 |
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| 134. |
The most abundant inert gas is___________. |
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Answer» Correct Answer - Argon Argon |
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| 135. |
In order to prevent the hot metal filament from getting burnt, when the electric current is switched on, the bulb is filled withA. `CH_(4)`B. an inert gasC. `CO_(2)`D. `CI_(2)` |
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Answer» Correct Answer - b Inert gases do not support combustion |
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| 136. |
The coloured discharge tubes for advertisement mainly containsA. XeB. NeC. HeD. Ar |
| Answer» Correct Answer - b | |
| 137. |
The oxidation states of the most electronegative element in the products of the reaction between `BaO_2` with dilute `H_2SO_4` areA. `0` and `-1`B. `-1` and `-2`C. `-2` and `0`D. `-2` and `-1` |
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Answer» Correct Answer - D `BaO_(2) + H_(2) SO_(4) rarr BaSO_(4) + H_(2) O` The oxidation state of `O` in `BaSo_(4)` is `- 2`. The oxidation state of `O` in `H_(2) O_(2)` is `- 1`. |
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| 138. |
There is no `S-S` bond inA. `S_2 O_4^(2-)`B. `S_2 O_5^(2-)`C. `S_2 O_3^(2-)`D. `S_2 O_7^(2-)` |
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Answer» Correct Answer - D `O^(Ө)-underset(underset(O)(||))overset(overset(O)(||))(S)-O- underset(underset(O)(||))overset(overset(O)(||))(S)-O^(Ө)` |
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| 139. |
Discovery of noble gas compounds were the basic of formation of an ionic solid , dioxigenyl hexafluoridoplatinate (V) `O_(2)^(oplus)[PtF_(6)]^(Θ)` when `O_(2)` reacts with `PtF_(6)` .This experiment was carried out byA. Bartlett and LohmanB. RamsayC. DawarD. Fischer -Ringe |
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Answer» Correct Answer - c Ionisation enithalpy of Ar is very high |
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| 140. |
Which one of the following does not exist?A. `XeF_(2)`B. `XeF_(4)`C. `ArF_(2)`D. `XeF_(6)` |
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Answer» Correct Answer - c `Xe + PtF_(6) rarr Xe^(Theta)[PtF_(6)]^(Theta) overset (excess PtF_(6)) underset([XeF]^(Theta) [Pt_(2)F_(11)]^(Theta)` |
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| 141. |
The forces of cohesion in liquid helium areA. covalentB. ionicC. van der waalsD. metallic |
| Answer» Correct Answer - c | |
| 142. |
The inert gas present in atmosphere areA. He and NeB. He, Ne and ArC. He, Ne ,Ar and KRD. He, Ne, Ar, Kr and Xe |
| Answer» Correct Answer - d | |
| 143. |
Radon was discovered byA. DornB. RamsayC. RayleighD. none of these |
| Answer» Correct Answer - a | |
| 144. |
Assertion :Ne and Ar do not form any chemical compound Reason :They have `ns^(2)sp^(6)` fully filled valence shell electronic configurationA. If both (A) and (R ) are correct and (R ) is the correct explanation of (A)B. If both (A) and (R ) are correct,but (R ) is the correct explanation of (A)C. If (A) is correct but (R ) is incorrectD. If (A) is incorrect but (R ) is correct |
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Answer» Correct Answer - b Correct Reason: `Ne` and `Ar` have very high ionisation energy. |
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| 145. |
The value of ionisation potential for inert gases is ________. |
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Answer» Correct Answer - Zero Zero |
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| 146. |
Which gas is filled in element bulbs/tubes?A. `O_(2)`B. `N_(2)`C. `Ar`D. `He` |
| Answer» Correct Answer - c | |
| 147. |
The noble gas having the lowest atomic numbers is _______. |
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Answer» Correct Answer - Hellum Hellum |
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| 148. |
Argon was discovered byA. CavendishB. LavoisierC. RayleighD. Thomson |
| Answer» Correct Answer - b | |
| 149. |
The oxide that gives `H_(2)O_(2)` on treatment with a dilute acid isA. `PbO_2`B. `Na_2 O_2`C. `MnO_2`D. `TiO_2` |
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Answer» Correct Answer - B Only true peroxides which have `O-O-bond` give hydrogen perxide with dilute acids. `Na_(2) O_(2) + H_(2) SO_(4) rarr Na_(2) SO_(4) + H_(2) O_(2)` Note : (i) But peroxide with conc. Acids leberates `H_(2) O_(2)` and `O_(2)`, e.g. `BaO_(2) + H_(2) SO_(4) (dil.) rarr BaSO_(4) + H_(2) O_(2)` `BaO_(2) + 2H_(2) SO_(4) (conc.) rarrr 2 BaSO_(4) + 2 H_(2) O_(2) + O_(2)` (ii) Superoxides (e.g., `KO_(2), RbO_(2), CsO_(2))` react with water to give `H_(2) O_(2)` and `O_(2)`. `2 KO_(2) + 2H_(2) O rarr 2 KOH + H_(2) O_(2) + O_(2)`. |
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| 150. |
Which of the oxdies behave both as neutral oxide and suboxide ? (a) `N_(2)O` , b. `NO`, c. `C_(3)O_(2)` , d. `CO` |
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Answer» (a) `N_2 O` acts both as neutral oxide and suboxide. (b) `NO` is neutral oxide. (c) `C_3 O_2` is suboxide. (d) `CO` is neutral oxide. |
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