InterviewSolution
Saved Bookmarks
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. |
In electrolysis of `NaCl` when `Pt` electrode is taken `H_(2)` is liberated at cathode while `Hg` cathode it forms sodium amalgam becauseA. Hg is more inert than PtB. more voltage is required to reduce `H^(+)` at Hg than at PtC. Na is dissolved in Hg while it does not dissove in PtD. concentration of `H^(+)` ions is larger when Pt electrode is taken |
|
Answer» Correct Answer - D Voltage required to reduce ions changes with the nature of electrode. No `H_(2)` gas is liberated as more voltage is required to reduce `H^(+)` at Hg than at Pt. |
|
| 2. |
Which among the following is kinetically inert towards water?A. NaB. BeC. CaD. K |
|
Answer» Correct Answer - B Na, K and Ca decompose water by evolving hydrogen gas. However Be does not react with water even when red hot. Its protective oxide layer survives even at high temperature. |
|
| 3. |
Which ions are produced when anhydrous KF is mixed with conc. HF?A. `K^(+),H^(+),F^(-)`B. `{KF^(+)(HF^(-))}`C. `KH^(+),F^(-)`D. `K^(+),HF_(2)^(-)` |
| Answer» Correct Answer - D | |
| 4. |
Fill up the blanks with appropriate choice. Lithium and magnesium react slowly with water. their hydroxides are_____soluble in water. Carbonates of Li and Mg____easily on heating. Both LiCl and `MgCl_(2)` are_____in ethanol and are_______.they crystallise from their aqueous solutions as_____.A. More, do not decompose, soluble, hygroscopic, hydratesB. less, decompose, soluble, deliquescent, hydratesC. freely, sublime, insoluble, deliquescent, anhydrousD. freely, docompose, soluble, hygroscopic, crystals |
| Answer» Correct Answer - B | |
| 5. |
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 -1B. `-1` and -2C. `-2` and 0D. `-2` and +1 |
| Answer» Correct Answer - B | |
| 6. |
An excess of `KO_(2)` is placed in a closed container of `CO_(2)`(g). After reaction is completed. Will the gas pressure be same, greater or less than initial value. Example. |
|
Answer» `2KO_(2(s))+CO_(2(g))toK_(2)CO_(3(s))+(3)/(2)O_(2(g))` the gas pressure will increase as number of moles of gaseous product is 3/2 while that of gaseous reactant was one. |
|
| 7. |
Write balanced equations for reactions between a. `Na_(2)O_(2)` and water b. `KO_(2)` and water c. `Na_(2)O` and `CO_(2)` |
|
Answer» (a) The balanced chemical equation for the reaction between `Na_(2)O_(2)` and water is: `2Na_(2)O_(2(s)) + 2H_(2)O_((l)) rarr 4NaOH_((aq))+O_(2(aq))` (b) The balanced chemical equation for the reaction between `KO_(2)` and water is: `2KO_(2(s))+2H_(2)O_((l)) rarr 2KOH_((aq))+H_(2)O_(2(aq))+O_(2(g))` (c) The balanced chemical equation for the reaction between `Na_(2)O` and `CO_(2)` is: `Na_(2)O_((s))+CO_(2(g))rarr Na_(2)CO_(3)` |
|
| 8. |
Among `KO_(2),ALO_(2)^(Θ)`,`BaO_(2)` and `NO_(2)^(+)`,unpaired electrons is present in .A. `NO_(2)^(+) and BaO_(2)`B. `KO_(2) and AlO_(2)^(-)`C. `KO_(2)` onlyD. `BaO_(2)` only |
| Answer» Correct Answer - C | |
| 9. |
The stability off `K_(2)O,K_(2)O_(2) and KO_(2)` is in order `K_(2)O lt K_(2)O_(2) lt KO_(2)`. This increasing stability as the size of metal ion increases is due to stabilisation ofA. larger cation by smaller anions through lattice energy effectsB. larger cation by larger anions through lattice energy effectsC. smaller cations by smaller anions through melting pointD. smaller cations by larger anions through melting point. |
| Answer» Correct Answer - B | |
| 10. |
A metal `M` readily forms its sulphate `MSO_(4)` which is water soluble. It forms its oxide `MO` which becomes inert on heating. It forms its insoluble hydroxide `M(OH)_(2)` which is soluble in `NaOH` solution. Then `M` isA. `Be`B. BaC. CaD. Mg |
| Answer» Correct Answer - A | |
| 11. |
Two metals X and Y belong to the cond group of periodic table. X forms insoluble oxide but soluble sulphate. Y forms a soluble oxide but insoluble sulphate. Hydroxide of metal X is soluble in NaOH while that of metal Y is insoluble in NaOH. What are metals X and Y?A. X=Be,Y=BaB. X=Mg,Y=CaC. X=Ca,Y=SrD. X=Ba,Y=Mg |
|
Answer» Correct Answer - A BeO-Insoluble, `BeSO_(4)`-soluble BaO-soluble, `BaSO_(4)`-Insoluble `Be(OH)_(2)`-soluble in NaOH `Ba(OH)_(2)`-insoluble in NaOH |
|
| 12. |
Plaster of Paris is obtained when gypsum is heated toA. 293 KB. 493 KC. 593 KD. 393 K |
|
Answer» Correct Answer - D `2CaSO_(4).2H_(2)Ooverset(393K)to2CaSO_(4).(1)/(2)H_(2)O+3H_(2)O` Above 393 K no water of crystallization is left and anhydrous calcium sulphate called head burnt plaster is formed. It is so called because it loses the properties of setting with water. Gypsum should not be allowed to come in contact with C containing fuel otherwise some of it will be reduced to calcium sulphite. |
|
| 13. |
Formula of gypsum salt isA. `CaSO_(4)*2H_(2)O`B. `CaSO_(4)*(1)/(2)H_(2)O`C. `2CaSO_(4)*H_(2)O`D. `CaSiO_(3)` |
| Answer» Correct Answer - A | |
| 14. |
Which of the followingg elements does not form hydride by direct heating with dihydrogen?A. `Be`B. MgC. SrD. Ba |
|
Answer» Correct Answer - A All the elements except beryllium combine with hydrogenn upon heating to form their hydrides, `NH_(2)`. `BeH_(2)`, however, can be prepared by the reaction of `BeCl_(2)` with `LiAlH_(4)`. `2BeCl_(2)+LiAlH_(4) to 2BeH_(2)+LiCl+AlCl_(3)`. |
|
| 15. |
By adding gypsum to cementA. setting time of cement becomes lessB. setting time of cement increasesC. colour of cement becomes lightD. shining surface is obtained |
|
Answer» Correct Answer - B The purpose of addin gypsum is only to slow down the process of setting of the cement so that it gets sufficiently hardened. |
|
| 16. |
Assertion: `CaCO_(3)` is prepared by passing carbon dioxide gas through slaked lime. Reason: Passingg excess of `CO_(2)` through slaked lime leads to the formation off quick lime.A. If both assertion and reason are true and reason is the correct explanation of assertionB. If both assertion and reason are true but reason is not the correct explanation of assertionC. If assertion is true but reason is false.D. If both assertion and reason are false. |
|
Answer» Correct Answer - C `underset("Slaked lime")(Ca(OH)_(2)+CO_(2) to CaCO_(3)+H_(2)O` Excess of `CO_(2)` leads to the functions of human body, we need monovalent Na and K ions and divalent Mg and Ca ions, which are found in large proportions I biological fluids. |
|
| 17. |
Slaked lime reacts with chlorine to formA. `CaCl_(2)`B. `CaO`C. `Ca(OC l)_(2)`D. `CaCO_(3)` |
|
Answer» Correct Answer - C `2Ca(OH)_(2)+2Cl_(2)toCaCl_(2)+underset("Bleaching powder")(Ca(OC l)_(2))+2H_(2)O` |
|
| 18. |
An element X burns in nitrogen to give a compound Y which on reaction with water gives a compound Z and a gas with a pungent smell. Z can be used during construction and white washing. When excess of `CO_(2)` is bubbled through Z, a compound P is formed which on heeating decomposes to give a compourless, odourless gas. identify X, Y, Z and P.A. `X-Ca,Y-Ca_(3)N_(2),Z-Ca(OH)_(2),P-Ca(HCO_(3))_(2)`B. `X-Mg,Y-MgO,Z-Mg(OH)_(2),P-MgCO_(3)`C. `X-Ca,Y-Ca_(3)N_(2),Z-Ca(OH)_(2),P-CaCO_(3)`D. `X-Ca,Y-CaO,Z-Ca(OH)_(2),P-Ca(HCO_(3))_(2)` |
|
Answer» Correct Answer - A `underset((X))(3Ca)+N_(2)to underset((Y))(Ca_(3)N_(2))` `Ca_(3)N_(2)+6H_(2)O to underset((Z))(3Ca(OH)_(2))+underset(("gas with a pungent smell"))(2NH_(3))` `underset((Z))(Ca(OH)_(2))+underset("excess")(CO_(2)) to underset((P))(Ca(HCO_(3))_(2)` `underset((P))(Ca(HCO_(3))_(2))overset("heat")to CaCO_(3)+H_(2)O+CO_(2)` |
|
| 19. |
When sodium is added in scanty water, it catches fire. In this process which one of the following burns ?A. NaB. `H_(2)O`C. `H_(2)`D. NaOH |
|
Answer» Correct Answer - C `H_(2)` gas produced during the reaction which burns in process. `2Na+2H_(2)O to 2NaOH+H_(2)` |
|
| 20. |
The element A burns in nitrogen to give an ionic compound B. the compound B reacts with water to give C and D. A solution of C becomes milkly on bubbling carbon dioxide. What is the natrue of compound (D)?A. AcidicB. BasicC. AmphotericD. Neutral |
|
Answer» Correct Answer - B `A overset("burn, nitrogen")to underset("ionic compound")(B) overset(H_(2)O)to underset("milky solution")underset(darr +CO_(2))(C)+D` Since the solution of C becomes milky on bubbling `CO_(2)` into it, C is lime water `(Ca(OH)_(2))`. Thus, the element nitrogen. nitrides on reacting with water give the corresponding hydroxide and ammonia. therefore. A is calcium (Ca). B is calcium nitride `(Ca_(3)N_(2))`. C is lime water `Ca(OH)_(2)`. D is ammonia `(NH_(3))`. |
|
| 21. |
Alkali metals are not found in free state due to their highly reactive nature. This is due toA. their large size and low ionisation enthalpyB. their large size and high ionisation enthalpyC. their low ionisation enthalyp and high electron gain enthalpyD. their tendency to impart colour to the flame. |
| Answer» Correct Answer - A | |
| 22. |
What happens when carbon dioxide gas is bubbled through lime water in small amount ? |
| Answer» When excess of `CO_(2)` is passed through lime water the white precipitate of `CaCO_(3)` dissolves to form calcium hydrogen carbonate. | |
| 23. |
Which of the following is incrrect ?A. Alkaline earth metals like alkali metals have high electrical and thermal conductivities.B. Alkaline earth metls are more electropositive (or metallic) than alkali metals.C. The electropositive (or metallic) character of alkaline earth metals increases down the group.D. None of these |
|
Answer» Correct Answer - B On account of relatively low ionization enthalpies, group 2 elements have a strong tendency to lose both the valence electrons forming dipositive cations. Hence, they show strong electropositive character which increases on going down the group because of decrease of ionization enthalpies. However, group 2 elements are less electropositive than group 1 elements because total energy required to yield gaseous `M^(2+)` ions for group 2 elements is over four times greater than the energy required to yield `M^(+)` ions for group 1 elements. |
|
| 24. |
The reducing power of a metal depends on various factors. Suggest the factor which makes Li, the strongest reducing agent in aqueous solution.A. Sublimation enthalpyB. Ionisation enthylpyC. Hydration enthalpyD. Electron-gain enthalpy |
|
Answer» Correct Answer - C With small size of `Li^(+)` ion, lithium has the highest hydration enthalpy which accounts for its higgh negative `E^(@)` value and its high reducing power. |
|
| 25. |
Calcium sulphate is sparingly soluble inA. benzeneB. alcoholC. acetic acidD. water |
|
Answer» Correct Answer - D Calcium suphate is an ionic compound. Thus, it dows not dissolve in organic solvents. On account of relatively large lattice enthalpy, it is sparingly soluble in water and solubility decreases as the temperature increases. |
|
| 26. |
Which of the following is incorrect about lithium ??A. LiOH is a strong baseB. Unlike other alkali metals, Li does not react with ethyne to from lithium ethynide.C. Unlike other alkali metals, Li forms dilithium acetylide on heating with C.D. Lithium has a greater tendency to form complexes than other alkali metals. |
|
Answer» Correct Answer - A LiOH is a weak base because it is only sparingly soluble in water while the hydroxides of other alkali metals are strong bases as they are more soluble in water. `2M+CH-=CHoverset(liq." "NH_(3))tooverset(+)(M)overset(-)(C)-=overset(-)(C)overset(+)(M)+H_(2)` `(M=Na,K,Rb,Cs)` `2LiJ+2Coverset(Delta)tounderset("Dilithium acetylide")(Li^(+)overset(-)(C)-=overset(-)(C)Li)` |
|
| 27. |
Which of the following is only sparingly soluble in water?A. `Li_(2)CO_(3)`B. `Li_(3)PO_(4)`C. `LiF`D. `LiOH` |
|
Answer» Correct Answer - D `Li_(2)CO_(3),Li_(3)PO_(4)`, and LiF are all insoluble in water and LiOH is only sparingly soluble. The rest of the alkali metals form soluble compounds. |
|
| 28. |
The pair of compounds which cannot exist in solution is:A. `NaHCO_(3)`B. `Na_(2)CO_(3)`C. `NaOH`D. `NaCl` |
| Answer» Correct Answer - A::C | |
| 29. |
Which of the following bicarbonate does not exist in solid state?A. `LiHCO_(3)`B. `KHCO_(3)`C. `CsHCO_(3)`D. `NaHCO_(3)` |
| Answer» Correct Answer - A | |
| 30. |
Which of the following bicarbonate does not exist in solid state?A. `NaHCO_(3)`B. `KHCO_(3)`C. `Ca(HCO_(3))_(2)`D. `RbHCO_(3)` |
|
Answer» Correct Answer - C Calcium bicarbonate exists in the form of solution. |
|
| 31. |
Sodium peroxide which is a yellow solid, when exposed to air becomes white due to the formation of:A. NaOH and `Na_(2)CO_(3)`B. NaOH and `H_(2)O_(2)`C. `Na_(2)O` and `O_(3)`D. `Na_(2)O` |
|
Answer» Correct Answer - A Sodium peroxide is a plate yellow powder. On exposure, it becomes white as if reacts with moisture and carbon dioxide: `2Na_(2)O_(2)++2H_(2)Orarr4NaOH+O_(2)` `2Na_(2)O_(2)+2CO_(2)rarr2Na_(2)CO_(3)+O_(2)` |
|
| 32. |
A white solid X on heating gives a white solid Y and an acid gas Z. gas Z is also given out when X reacts with an acid. The compound Y is also formed if caustic soda is left open in the atmosphere. X, Y and Z areA. `X-NaHCO_(3),Y-Na_(2)CO_(3),Z-CO_(2)`B. `X-Na_(2)CO_(3),Y-NaOH,Z-CO_(2)`C. `X-Na_(2)CO_(3),Y-NaHCO_(3),Z-CO_(2)`D. `X-NaOH, Y-NaHCO_(3),Z-CO_(2)` |
|
Answer» Correct Answer - A `underset((X))(2NaHCO_(3)) to underset((Y))(Na_(2)CO_(3))+underset((Z))(CO_(2))+H_(2)O` `underset((X))(NaHCO_(3))+HCl to NaCl+ underset((Z))(CO_(2))+H_(2)O` `underset(("atmosphere"))(2NaOH+CO_(2)to underset((Y))(Na_(2)CO_(3))+H_(2)O` |
|
| 33. |
Which of the following statements is correct?A. Sodium carbonate decomposes on heatingB. sodium biarbonate is more soluble in water than potassium bicarbonate.C. sodium when heated with excess of `O_(2)`, gives peroxideD. Lithium halides are highly ionic in nature. |
|
Answer» Correct Answer - C Only (c) is the correct statement, others are incorrect and these are corrected as (a) Lithium carbonate decomposes on heating. (b) Potassium bicarbonate is more soluble in water than sodium bicarbonate. (d) lithium halides are highly covalent in nature. |
|
| 34. |
What happens when `H_(2)` is passed over lithium at 1073K?A. Covalent lithium hydride is formedB. Coloured complex is formedC. Ionic lithium hydride is formedD. No reaction |
|
Answer» Correct Answer - C Lithium fforms ionic hydride having high melting point. |
|
| 35. |
Which among the following is the strongest reducing agent?A. KB. NaC. AlD. Mg |
| Answer» Correct Answer - A | |
| 36. |
Among alkali metals. Which one is the strongest reducing agent? |
| Answer» Correct Answer - Lithium. | |
| 37. |
On reaction with dihydrogen the alkali metalsA. form hydrides which are ionic solids with high melting pointsB. form hydrides which are molcular solids with low melting pointsC. form hydrides which are ionis solids with low melting pointsD. form hydrides which are non-stoichiometric. |
|
Answer» Correct Answer - A Alkali metals react with dihydrogen to form hydrides which are ionic solids with high melting points. |
|
| 38. |
If an element has more negative value of electrode potential, then what will be its expected reducing power? |
| Answer» It will be more reducing in nature or stronger reducing agent. | |
| 39. |
If standard electrode potential of an element x is -1.70V and of another y is +1.07V. Which one of these is strong reducing agent? |
| Answer» Correct Answer - Element x. | |
| 40. |
Lithium is the strongest reducing agent though it has highest ionisation enegy in its group. Which of the followinng factors is responsible for making Li the strongest reducing agent?A. Large heat of atomisationB. Smaller sizeC. Large sublimation energyD. Large amount of hydration enthalpy |
|
Answer» Correct Answer - D Large amount of hydration energy makes it strongest reducing agent inspite of its highest ionisation enthalpy. `M_((s)) underset("energy")overset("Sublimation")to M_((g)) underset("Energy")overset("Ionisation")to M_((g))^(+) underset("energy")overset("Hydration")to M_((aq))^(+)` |
|
| 41. |
Statement-1: Lithium is the strongest reducing agent is aqueous solution. Statement-2: Lithium cannot be obtained by chemical reduction of its ore.A. Statement-1 is true, statement-2 is true, statement-2 is a correct explanation for statement-1B. Statement-1 is true, statement-2 is true, statement-2 is not correct explanation for statement-1C. Statement-1 is true, statement-2 is falseD. Statement-1 is false, statement-2 is true |
| Answer» Correct Answer - B | |
| 42. |
Present a comparative account of the alkali and alkaline earth metals with respect to the following characteristics. (a) Tendency to form ionic/covalent compounds (b) Nature of oxides and their solubility in water (c) Formation of oxoslats (d) Solubility of oxosalts (e) Thermal stability of oxosalts |
|
Answer» (a) Alkaline earth metals form compounds which are predominantly ionic but less ionic than the corresponding compounds of alkali metals due to nuclear charge and small size. Oxides of alkaline earth metals ate less basic than corresponding oxides of alkali metals. the oxides dissolve in water to form basic hydroxides and evolve a large amount of heat. The alkaline earth metal hydroxides, are however less basic and less stable than alkali metal hydroxides. (c) Alkaline earth metals form oxoacids as alkali metals. The formation of alkali metal oxoacids is much more faster and stronger than their corresponding alkaline earth metals due to increased nuclear charge and small size. (d) Solubility of alkaline oxoacids is more than alkali oxoacids because alkaline earth metals have small size of cation and higher hydration energy. Salts like `CaCO_(3)` are insoluble in water. (e) Oxosalts of alkali metals are thermally more stable then those of alkaline earth metals. As the electropositive character increases down the group, the stability of carbonate and hydrogen carbonates of alkali metal increases. Whereas for alkaline earth metals, carbonate decomposes on heating to give carbon dioxide and oxygen. |
|
| 43. |
Lithium is the srtrongest reducing agent in the aqueous solution because of the highestA. enthalpy of sublimationB. ionization enthalpyC. enthalpy of hydrationD. all of these |
|
Answer» Correct Answer - C The standard reduction electrode potential, `E^(@)(M^(+)//M)`, which measures the reducing power in aqueous solutions represents the overally change `M(s)toM^(+)(aq.)+e^(-)` its negative value is favoured by lower sublimation enthalpy. All alkali metals have similar ionization enthalpies. Li has the highest ionization enthalpy as well as the highest hydration enthalpy as well as the highest hydration enthalpy. However, energy reqruied to ionize Li is more than comprensated by the large amount of energy released during the hydration of `Li^(+)`(g) ion.Thus, the highest hydration enthalpy (among all alkali metal ions) of Li accounts for high negative `E^(@)` and its high reducing power. |
|
| 44. |
Crystalline sodium chloride is a bad conductor of electricity while molten NaCl and its aqueous solution conduct electricity. This is becauseA. crystalline sodium chloride contains molecules onlyB. the ions present in it are not free to move in solid stateC. sodium chloride is a covalent crystalD. solid substrances do not conduct electricity. |
|
Answer» Correct Answer - B `Na^(+) and Cl^(-)` ions are free to move only in molten state or aqueous solution. |
|
| 45. |
The alkali metal cation having the least ionic mobility isA. `Li^(+)`B. `Na^(+)`C. `K^(+)`D. `Cs^(+)` |
|
Answer» Correct Answer - A The extent of hydration depends upon the size of the ion. Smaller the size of the ion, more highly it is hydrated and, hence, greater is its hydrated ionic radius, and less is its ionic mobility (condcutance). Thus, the order of ionic mobility is `Li^(+)ltNa^(+)ltK^(+)ltRb^(+)ltCs^(+)` |
|
| 46. |
Above `380^(@)C`, lithium is miscible with moltenA. NaB. KC. RbD. all of these |
|
Answer» Correct Answer - A `Li^(+) (0.76 Å)` is much smaller than the other ions `[Na^(+) (1.02 Å), K^(+) (1.38 Å), Rb^(+) (1.52 Å), "and" Cs^(+) (1.67Å)]`. For this reason, Li only mixes with Na above `380^(@)`. It is immiscible with the metals K, Rb and Cs, even when molten. Even Li does not form substitutional alloys with them. In contrast, the other metlas Na, K, Rb, and Cs are miscible with each other in all proportions. |
|
| 47. |
`Mg_(3)P_(2)` on hydrolysis producesA. `Mg(OH)_(2)`B. `MgO`C. `PH_(3)`D. `P_(2)O_(3)` |
| Answer» Correct Answer - A::C | |
| 48. |
In castner-Keliner cell when brine is electrolysed, 23g of sodium is released is released on cathode, volume of `Cl_(2)(g)` released at 380 mm Hg at `0^(@)C` will beA. 22.4 LB. 11.2LC. 5.6 LD. 44.8L |
| Answer» Correct Answer - A | |
| 49. |
The most electronegative alkaline earth metal isA. BeB. MgC. CaD. Ba |
| Answer» Correct Answer - D | |
| 50. |
Why does magnesium from `Mg^(2+)` and not `Mg^(+)`?A. Magnesium (II) is insoluble in waterB. Commonly higher oxidation states are preferred by metalsC. Ionic radius of Mg(II) is smaller tha of Mg(I)D. High hydration energy as well as high latice energy of divalent magnesium ion |
| Answer» Correct Answer - D | |