InterviewSolution
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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.
| 1. |
Sodium thiosulphate, `Na_(2)S_(2)O_(3).5H_(2)O` is used in photography toA. Reduce the AgBr grains to metallic AgB. Convert metallic Ag to Ag saltC. Remove undecomposed AgBr as soluble silver thisolphate complexD. Remove reduced silver |
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Answer» Correct Answer - C `Na_(2)S_(2)O_(3)+2 AgBr rarr underset("Soluble")(Ag_(2)S_(2)O_(3))+2NaBr` |
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| 2. |
On dissolving moderate amount of sodium metal in liquid ammonia at low temperature, which of the following does not occur ?A. Blue-colured solution is obtainedB. Ammoniated `Na^(o+)` ions are formed in solutionC. Liquid ammonia becomes good conductor of electricityD. The liquid ammonia remains diamagnetic |
| Answer» Correct Answer - D | |
| 3. |
Match the compounds given in (X) with uses in (Y), (X) A. NaOH , (Y) 1. Glass (X) B. `Na_(2)S_(2)O_(3)` , (Y) 2. Germicide (X) C. NaCN , (Y) 3. Antichlor (X) D. `Na_(2)CO_(3)` , (Y) 4. Soap Codes:A. A 4, B 3, C 2, D 1B. A 3, B 4, C 1, D 2C. A 2, B 3, C 4, D 1D. A 1, B 2, C 3, D 4 |
| Answer» Correct Answer - A | |
| 4. |
The pairs of compounds which cannot exist together in aqueous solution areA. `NaHCO_(3)+NaOH`B. `NaHCO_(3)+Na_(2)CO_(3)`C. `Na_(2)CO_(3)+NaOH`D. `NaOH+NaCI` |
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Answer» Correct Answer - A `NaHCO_(3)` is a sodium salt of weak acid, while NaOH is a strong base, that is why they react and cannot exist together in solution. `NaHCO_(3)+NaOH rarr Na_(2)CO_(3)+H_(2)O` |
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| 5. |
Lithium imparts sky-blue colour to the flame. |
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Answer» Correct Answer - F Lithium imparts crimson colour to the flame. |
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| 6. |
A ceratin compound (A) imperts a golden yellow flame and exhibits following reactions: a. When a concentrated solution of (A) is boiled with Zn power, hydrogen gas is evolved. b. When an aqueous solution of (A) is added to an precipitate is obtained, which dissolves in excess of solution (A). Identify (A) and give equations for reactions in (ii). |
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Answer» a. `underset((A))(NaOH_((aq)))+Zn rarr underset("zincate")underset("Sodium")(Na_(2)ZnO_(2(aq)))+underset("gas")underset("Hydrigon")(H_(2)uarr)` b. `underset((A))(NaOH_((aq)))+underset("chloride")underset("Stannous")(SnCI_(2))rarrunderset("White ppt".)(Sn(OH)_(2)darr) + 2NaCI` `Sn(OH)_(2)+NaOH rarr underset("Solulble")(Na_(2)SnO_(2))+2H_(2)O` Hence, (A) is NaOH and imparts golden yellow colour to the flame. |
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| 7. |
Potassium gives a -------- colour to the Bunsen flame.A. violetB. blueC. apple greenD. brick red |
| Answer» Correct Answer - A | |
| 8. |
Which of the following compound(s) will impart a golden yellow colour to the Bunsen flame ?A. `KCI`B. `K_(2)CO_(3)`C. `NaCI`D. `Na_(2)CO_(3)` |
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Answer» Correct Answer - C::D Na imparts golden yellow colour to the Bunsen flame. |
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| 9. |
Assertion (A): Alkali metals can form ionic hydrides which contain hydride ion, H. Reason (R ): The alkali metals have low EN. Their hydrides conduct electricity, when fused and liberate hydrogen at the anode.A. Statement I is true, Statement II is true, Statement II is the correct explanation for statement I.B. Statement I is true, Statement II is true, Statement II is not the correct explanation for Statement I.C. Statement I is true, Statement II is false.D. Statement I is false, Statement II is true. |
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Answer» Correct Answer - A Statement I and Statement II are correct and Statement II gives the correct explanation. |
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| 10. |
Give reasons for the following: a. Alkli metals do not occur free in nature. b. Alkali metal salts impart characteristic colour to the flame. c. Caesium is used in photoelectric cell. d. Alkali metals are good reducing agents in aqueous medium. |
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Answer» a. Alkali metals are highly reactive because of their large size and low ionisation enthalpy values and hence they do not occur free in nature. They readily combine with oxygen, moisture and carbon dioxide present in air. b. When alkali metal salts are heated in the Bunsen flame, they absorb energy. The valence shell electron gets excited to higher energy le4vel. When the exited electron returns to its original energy level, excess energy is emitted in the form of electromagnetic radiation which falls in the visible region, thereby imparting colour to the flame. Since the ionisation energy decreases form Li to Cs, the amount of energy released increases form Li to Cs. Thus, the frequency of light emitted increases in accordance with the formula E= hv. Hence, different alkali metals import charactercistic colour to the flame. c. Because of low ionisation enthalpy, caesium is used in photoelectric cells, since low-energy photons (light) can eject electrons (s) form the surface. d. Alkali metals are good reducing agents because they can lose electron(s) easily on account of low ionisation enthalpy values. |
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| 11. |
Give reasons for the following: a. Alkali metals are soft and volatile. b. First ionisation enthalpies of alkali metals are low. |
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Answer» a. Alkali metals have only one valence electron per metal atom. The binding energies in the closed packed metal lattice are weak. That is why alkali metals are soft and volatile. b. Alkali metals have larger and the valence shell electron `(ns^(1))` is loosely bond and can be removed easily by providing low amount of energy. That is why the first ionisation enthalpies of all alkali metals are low. `M_((g))overset(IE_(1))rarr M_((g))^(o+)+ bar e` |
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| 12. |
Sodium hydride (NaH) when dissolved in water, producesA. Acidic solutionB. Basic solutionC. Neutral solutionD. Cannot be predicted |
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Answer» Correct Answer - B `NaH+H_(2)O rarr NaOH+H_(2)` |
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| 13. |
The correct order of stability for the following superoxides isA. `KO_(2)gtRbO_(2)CsO_(2)`B. `RbO_(2)gtCsO_(2)gtKO_(2)`C. `CsO_(2)gtRbO_(2)gtKO_(2)`D. `KO_(2)gtCsO_(2)gtRbO_(2)` |
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Answer» Correct Answer - C With the increase in size of metal ion `K^(o+) lt Rb^(o+) lt Cs^(o+)`, compatibility with superoxide ion `(O_(2)^(Θ))`, increases, resulting in increase in lattice energy or stability of the peroxide formed. |
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| 14. |
Assertion (A): Alkali metals are strong reducing agents. Reason (R ): They have only one electron to be lost form their valence shells.A. 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 not the correct explanation of (A).C. If (A) is correct, but (R ) is incorrect.D. If (A) is incorrect, but (R ) is correct. |
| Answer» Correct Answer - A | |
| 15. |
Alkali metals are strong reducing agents. |
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Answer» Correct Answer - T Due to strong tendency to lose electrons. |
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| 16. |
Lithium resembles magnesium in some respects though placed in a different group. |
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Answer» Correct Answer - T Diagonal relationship between Li and Mg |
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| 17. |
In the case of alkali metals, the covalent character decreases in the order.A. `MFgtMCIgtMBrgtMI`B. `MFgtMCIgtMIgtMBr`C. `MIgtMBrgtMCIgtMF`D. `MCIgtMIgtMBrgtMF` |
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Answer» Correct Answer - C As the size of halide ion decreases, `I^(Θ) gt Br^(Θ) gt CI^(Θ) gt F^(Θ)`, tendency to get polarised by cation `M^(o+)` decreases and hence convalent character decreases. |
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| 18. |
Arrange the following in order of the increasing covalent character: `MCI, MBr, MF, MI` (where M = alkali metals) |
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Answer» `{:(,MFlt,MCllt,MBrlt,MI),("Size of anion",F^(Θ)lt,Cl^(Θ)lt,Br^(Θ)lt,I^(Θ)),("Degree of polarisation",F^(Θ)lt,Cl^(Θ)lt,Br^(Θ)lt,I^(Θ)),("Covalent character",MFlt,MCllt,MBrlt,MI):}` With increasing size of the anion, degree of polarisation by the cation increses and hence the covalent character increases. |
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| 19. |
Sodium is more electropositive than magnesium. |
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Answer» Correct Answer - T Ionisation enthalpy of Na is less than than that of Mg, hence Na is more electropositive than Mg. |
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| 20. |
The electropositive character of alkali metals decreases with an increase in atomic number. |
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Answer» Correct Answer - F Due to the decrease in ionisation enthalpy down the group `(darr)`, the tendency to lose electrons, i.e. electropositive character increases down the group `(darr)`. |
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| 21. |
Assertion (A): NaOH is a stronger base than KOH. Reason (R ): KOH is more soluble in water than NaOH.A. 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 not the correct explanation of (A).C. If (A) is correct, but (R ) is incorrect.D. If (A) is incorrect, but (R ) is correct. |
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Answer» Correct Answer - D Correct assertion: KOH is stronger base than NaOH. |
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| 22. |
Sodium is ____________ electropositive than potassium. |
| Answer» Correct Answer - Less | |
| 23. |
Assertion (A): Aqueous solution of `Na_(2)CO_(3)` is alkaline in nature. Reason (R ): when dissolved in water, `Na_(2)CO_(3)` undergoes anionic hydrolysis.A. 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 not the correct explanation of (A).C. If (A) is correct, but (R ) is incorrect.D. If (A) is incorrect, but (R ) is correct. |
| Answer» Correct Answer - A | |
| 24. |
Sodium metal can be kept under:A. KeroseneB. BenzeneC. TolueneD. Alcohol |
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Answer» Correct Answer - A::B::C Since sodium does not react with kerosene, benzene and toluene also prevent the contact of atmospheric air with oxygen. |
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| 25. |
Assertion (A): Potassium is a stronger reducing agent than sodium. Reason (R ): IE of potassium is less than that of sodium.A. 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 not the correct explanation of (A).C. If (A) is correct, but (R ) is incorrect.D. If (A) is incorrect, but (R ) is correct. |
| Answer» Correct Answer - A | |
| 26. |
why a standard sollution of NaOH cannot be-prepared direct weighing cold NaOH ? |
| Answer» NaOH is deliquescent and reacts with atomospheric `CO_(2)` to form `Na_(2)CO_(3)`, thus NaOH is not pure but contains impurity of `Na_(2)CO_(3)`. | |
| 27. |
Which of the following salts does not form any precipitate with excess of NaOH ?A. `ZnCI_(2)`B. `FeCI_(3)`C. `CeCI_(3)`D. `CuSO_(4)` |
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Answer» Correct Answer - A `ZnCI_(2)+NaOH rarr Zn(OH)_(2)overset(NOH)rarr underset("Soluble")(Na_(2)ZnO_(2))` `FeCI_(3)+3NaOH rarr Fe(OH)_(3)darr ("brown ppt.") + 3NaCI` `CrCI_(3)+3NaOH rarr Cr(OH)_(3)darr +3NaCI` `CuSO_(4)+2NaOH rarr underset("Light blue ppt.")(Cu(OH)_(2)darr) + Na_(2)SO_(4)` |
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| 28. |
The first element of group different form its congeners, i.e. other members of the group in many ways. These differences may be due to the following: i. Small size of atom and ion. ii. High electronegativity. iii. Non-availibility of low lying d-orbitals. The first element of a group shows resemblence with the second element of the adjacent group on the right. This is known as diagonal relationship. Metal `(M)+N_(2)rarr` Nitride `overset(H_(2)O)underset("Hydrolysis")rarr NH_(3)` Metal (M) can beA. LiB. NaC. KD. Mg |
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Answer» Correct Answer - A::D `6Li+N2 rarr 2Li_(3)N` `3H_(2)O+Li_(3)N rarr 3LiOH+NH_(3)` `6Mg+N_(2)rarr 2Mg_(3)N` `Mg_(3)N+3H_(2)O rarr 3Mg(OH)_(2)+NH_(3)` Due to the small size of cation, `M(o+)` and anion `N6(3-)`, lattice energy of nitride formed is high and hence `Li^(o+)` and `Mg^(2+)` form stable nitride. |
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| 29. |
In Castner-Kellner cell, sodium hydroxide is formed in the central compartment. |
| Answer» Correct Answer - T | |
| 30. |
Which of the following is strongly hydrated in aqueous solution ?A. `Li^(o+)`B. `Na^(o+)`C. `K^(o+)`D. `Cs^(o+)` |
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Answer» Correct Answer - A `Li^(o+)` due to highest positive charge density gets hydrated to maximum extent. |
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| 31. |
One of the natural minerals of sodium is tincal. Its formula isA. `Na_(2)CO_(3).10H_(2)O`B. `NaNO_(3)`C. `Na_(2)B_(4)O_(7).10H_(2)O`D. `NaCI` |
| Answer» Correct Answer - C | |
| 32. |
Which of the following is the best `CO_(2)` absorber as well as source of `O_(2)` in space capsule ?A. `KOH`B. `K_(2)O_(2)`C. `KO_(2)`D. `LiOH` |
| Answer» Correct Answer - C | |
| 33. |
The compounds(s) formed upon combustion of sodium metal excess air is/areA. `Na_(2)O_(2)`B. `Na_(2)O`C. `NaO_(2)`D. NaOH |
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Answer» Correct Answer - A::B `4Na+O_(2)rarr 2Na_(2)O` and `2Na+2O_(2)rarr 2Na_(2)O_(2)` |
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| 34. |
The compounds used in Solvay process areA. `Na_(2)SO_(4)`B. `NaCI`C. `NH_(3)`D. `CaCO_(3)` |
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Answer» Correct Answer - B::C::D NaCI, `NH_(3)` and `CaCO_(3)` are the metrials used. |
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| 35. |
In the manufacture of sodium carbonate, following reactions are involved: `(A) overset(Delta)rarr (B) + CO_(2)` `(B) +H_(2)O rarr (C ) overset(+NH_(4)CI rarr (D)overset(+H_(2)O)rarr underset("Solution")(E )` `(E )+CO_(2)rarr (F)` `(F)+NaCI rarr (G) overset("Heat")rarr Na_(2)CO_(3)+CO_(2)+H_(2)O` (D) is a gas which is soluble in `H_(2)O` (A) isA. `Ca(HCO_(3))_(2)`B. `CaCO_(3)`C. `CaC_(2)`D. `NaHCO_(3)` |
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Answer» Correct Answer - B `underset((A))(CaCO_(3))overset(Delta)rarr underset((B))(CaO)+CO_(2)` `underset((B))(CaO)+H_(2)O rarr underset((C ))(Ca(OH)_(2))` `underset((C ))(Ca(OH)_(2))+2NH_(4)CI rarr underset("Water soluble gas")underset((D))(2NH_(3)uarr)+CaCI_(2)+2H_(2)O` `underset((D))(NH_(3))+H_(2)O rarr underset((E ))(NH_(4)OH_((s))` `underset((E ))(NH_(4)OH)+CO_(2)rarr underset((F))(NH_(4)HCO_(3))` `underset((F))(NH_(4)HCO_(3))+NaCI rarr underset(G)(NaHCO_(3))+NH_(4)CI` `underset((G))(2NaHCO_(3)) overset(Delta)rarr Na_(2)CO_(3)+H_(2)O+CO_(2)` |
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| 36. |
Write the balanced chemical equations for the following reactions. a. An aqueous solution solution of sodium nitrite is heated with zinc dust and caustic soda solution. b. Sodium iodate is added to a solution of sodium bisulphite. |
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Answer» a. Ammonia is produced. `3Zn+NaNO_(2)+5NaOH rarr 3Na_(2)ZnO_(2)+NH_(3)+H_(2)O` b. `4overset(Θ)OH+2H_(2)O+underset(x=0)(Zn) rarr underset(X-4= -2)(ZnO_(2)^(2-))+4H_(2)O+2e^(-)]xx3` `7H_(2)O+6e^(-)+underset(x=3)underset(x-4= -1)(NO_(2)^(Θ))rarr underset(x= -3)underset(x+3=0)(NH_(3))+2H_(2)O+OH` `5NaOH+NO_(2)^(Θ)+3Zn rarr 3ZnO_(2)^(2-)+NH_(3)+H_(2)O` (Add `6Na^(o+)` ions on both sides) `ulbar(5NaOH+NaNO_(2)+3Zn rarr 3Na_(2)ZnO_(2)+H_(2)O+NH_(3))` |
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| 37. |
Which of the following decomposes on healting ?A. `LiOH`B. `NaOH`C. `KOH`D. `CsOH` |
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Answer» Correct Answer - A `2LiOH rarr Li_(2)O+H_(2)` |
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| 38. |
Complete and balance the following chemical reactions: anhydrous potassium nitrate is heated with excess of metallic potassium. `KNO_(3)(s)+K(s)rarr` |
| Answer» `2KNO_(3(s))+10K_((s))rarr 6H_(2)O+N_(2)` | |
| 39. |
Explain why: (a) Lithium on being heated in air mainly forms the monoxide and not peroxide. (b) An aqueous solution of sodium carbonate gives alkaline test. |
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Answer» a. `Li^(o+)` ion is very small in size. It is stabilised more by smaller anion, i.e. oxide ion `(O^(2-))` as compared to peroxide ion `(O_(2)^(2-))` . b. An aquous solution of sodium carbonate gives alkaline tests because `Na_(2)CO_(3)` undergoes hydrolysis. `Na_(2)CO_(3)+H_(2)O rarr NaHCO_(3)+NaOH` or `CO_(3)^(2-)+H_(2)O rarr HCO_(3)^(Θ)+ .^(Θ)OH` |
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| 40. |
Lithium formsA. LiOB. `LiO_(2)`C. `Li_(2)O`D. `Li_(2)O_(2)` |
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Answer» Correct Answer - C `2Li+O_(2)rarr Li_(2)O`, due to comparable size of `Li^(o+)` and `O^(2-)` , `Li_(2)O` , is highly stable. |
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| 41. |
The material used in solar cells containsA. LithiumB. CalciumC. CeasiumD. Francium |
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Answer» Correct Answer - C Cs has the lowest ionisation enthalpy. |
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| 42. |
Sodium carbonate solution is alkaline due to hydrolysis of ____________ . |
| Answer» Correct Answer - `CO_(3)^(2-)` ion | |
| 43. |
The correct order of mobility of alkali metal ions in aqueous solution isA. `Li^(o+) gt Na^(o+) gt K^(o+) gt rb^(o+)`B. `Rb^(o+) gt Na^(o+)-=K^(o+) gt Li^(o+)`C. `Li^(o+) lt Na^(o+) lt K^(o+) lt Rb^(o+)`D. `Na^(o+)-=K^(o+) gt Rb^(o+) gt Li^(o+)` |
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Answer» Correct Answer - C Down the group `(darr)` with decrease in positive charge density of `M^(o+)` ion tendency to get hydrated decreases and hence the size of hydrated ion decreases. Thus moibility increases. `Li_((aq)) lt Na_((aq))^(o+) lt K_((aq))^(o+) lt Rb_((aq))^(o+)` |
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| 44. |
The correct order of mobility of alkali metal ions in aqueous solution isA. `K^(o+)gtRb^(o+)Na^(o+)gtLi^(o+)`B. `Rb^(o+)gtK^(o+)gtNa^(o+)gtLi^(o+)`C. `Li^(o+)gtNa^(o+)gtK^(o+)gtRb^(o+)`D. `Na^(o+)gtK^(o+)gtRb^(o+)gtLi^(o+)` |
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Answer» Correct Answer - B Smaller the size of the ion, more is the hydration and therefore lesser is the mobility. |
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| 45. |
Which of the following carbonates does not evolve `CO_(2)` on heating ?A. `Li_(2)CO_(3)`B. `Na_(2)CO_(3)`C. `K_(2)CO_(3)`D. `Cs_(2)CO_(3)` |
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Answer» Correct Answer - A `Li_(2)CO_(3)` being least stable due to size incompatibily of `Li^(o+)` and `CO_(3)^(2Θ)` ions, it decomposes most readily. `Li_(2)CO_(3)overset(Delta)rarr Li_(2)O+CO_(2)` |
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| 46. |
Which of the following carbonates does not evolve `CO_(2)` on heating ?A. `Li_(2)CO_(3)`B. `MgCO_(3)`C. `Na_(2)CO_(3)`D. `K_(2)CO_(3)` |
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Answer» Correct Answer - C::D `Na_(2)CO_(3)` and `K_(2)CO_(3)` are stable carbonates and thus do not decompose on heating. |
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| 47. |
Saltpete isA. `KNO_(3)`B. `NaNO_(3)`C. `NaCI`D. `Na_(2)CO_(3)` |
| Answer» Correct Answer - A | |
| 48. |
Chile salpeter isA. `KNO_(3)`B. `NaNO_(3)`C. `Na_(2)SO_(4)`D. `Na_(2)S_(2)O_(3)` |
| Answer» Correct Answer - B | |
| 49. |
sodium peroxide which is a yellow solid, when exposed to air becomes white due to the formation of:A. `H_(2)O_(2)`B. `Na_(2)O`C. `Na_(2)O` and `O_(3)`D. `NaOH` and `Na_(2)CO_(3)` |
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Answer» Correct Answer - D `Na_(2)O_(2)+2H_(2)O rarr 2NaOH+H_(2)O` `NaOH+CO_(2)rarr Na_(2)CO_(3)+H_(2)O` |
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| 50. |
Litopone is used as _____________ . |
| Answer» Correct Answer - Pigment | |