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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.
| 251. |
Which of the following is not an ore of magnesium?A. MagnesiteB. CarnalliteC. DolomiteD. Barytes |
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Answer» Correct Answer - D Barytes (heavy spar) is naturatlbarium sulphate `(BaSO_(4))`. Ba is mined as barytes. Magnesite is `MgCO_(3)`, carnallite is `KCl.MgCl_(2).6H_(2)O`, and dolomite is `MgCO_(3).CaCO_(3)`. |
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| 252. |
Which of the following is not an ore of magnesium?A. GypsumB. MagnesiteC. DolomiteD. Carnallite |
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Answer» Correct Answer - A Gypsum is `CaSO_(4).2H_(2)O`. The ores of Mg are magnesite `(MgCO_(3))`, dolomite `(MgCO_(3).CaCO_(3))`, and carnallite (KCl.`MgCl_(2).6H_(2)O`) |
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| 253. |
Celestite is an ore ofA. BaB. MgC. SrD. Ca |
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Answer» Correct Answer - C Sr and Ba are much less abundant but are well known because they occur as concentrated ores which are easy to extract. Sr is mined as celestite `(SrSO_(4))` and strontianite `(SrCO_(3))` while Ba is mined as barytes `(BaSO_(4))`. |
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| 254. |
The electronic configuration of Ca isA. `[Kr]4s^(2)`B. `[Ar]4s^(2)`C. `[Ne]4s^(2)`D. `[He]4s^(2)` |
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Answer» Correct Answer - B Atomic number of Ca is 20. thus, its electronic configuraiton is `1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)` or `[Ar]4s^(2)` The atoms of al alkaline earth metals have two s electrons in their outtermost shell `(ns^(2))`. As these elements have similar valency shell electronic configuration, they show regular gradation in their physical properties and exhibit similar chemical properties. |
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| 255. |
Alkali metals areA. strong reducing agentsB. strong oxidizing agentsC. both strong reducing and oxidizing agentsD. neither strong reducing nor strong oxidizing agents |
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Answer» Correct Answer - A Due to their strong tendency to lose the `ns^(1)` electron on account of low ionization enthalpies (gas phase) and highly negative standard reduction potentials (aqueous solution). |
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| 256. |
Calcium is obtained by theA. roasting of limestoneB. reduction of `CaCI_(2)` with carbonC. electrolysis of a solution of `CaCI_(2)` in waterD. electrolysis of molten `CaCI_(2)` |
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Answer» Correct Answer - D Calcium is obtained by the electrolysis of a fused mass consisting of six parts `CaCl_(2)` and one part `CaF_(2)` at about `700^(@)C` in an electrolytic cell made of graphite. |
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| 257. |
A solution of sodium metal in liquid ammonia is strongly reducing due to the presence ofA. solvated clectronsB. sodium amideC. sodium hydrideD. sodium atoms |
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Answer» Correct Answer - A Solution of sodium metal inliquid `NH_(3)` consists of solvated `Na^(+)` ions and solvated electrons: `Na+(x+y)NH_(3)to[Na(NH_(3))_(x)]^(+)+[e(NH_(3))_(y)]^(-)` reduction property is mainly due to solvated electrons. |
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| 258. |
Which of the following decomposes more readily than the other forming the oxide?A. `NaNO_(3)`B. `KNO_(3)`C. `LiNO_(3)`D. `RbNO_(3)` |
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Answer» Correct Answer - C The thermal stability of the nitrates decreases on moving down the group. |
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| 259. |
Which of the following does not react readily with water in spite of its favorable reduction potential ?A. BaB. SrC. CaD. Mg |
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Answer» Correct Answer - D Mg forms a protective layer of oxide. Thus, depite its favorable reduction potential, it does not reat readily unless the oxide layer is removed by amalgamating withmercury. In the formation of the oxide film, it resembles Al. |
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| 260. |
Be react with air, how many products will form? |
| Answer» Correct Answer - 3 | |
| 261. |
When water is added to compound (A) of calcium, solution of compound (B) is formed. When carbon dioxide is passed into the solution, it turns milky due to the formation of compound (C). If excess of carbon dioxide is passed into the solution milkiness disappears due to the formation of compound (D). Identify the compounds A,B,C and D. Explain why the milkiness disppears in the last step. |
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Answer» Appearance of milkiness on passing `CO_(2)` in the solution of compound B indicates that compound B is lime water and compound C is `CaCO_(3)`. Since, compound B is obtained by adding `H_(2)O` to compound A, therefore, compound A is quicklime, `CaO`. The reactions are as follows (i) `underset((A))underset("Calcium oxide")(CaO)+H_(2)O rarr underset((B))underset("Lime water")(Ca(OH)_(2))` (ii) `underset((B))(Ca(OH)_(2))+CO_(2)rarr underset(("Milkiness"))underset("Calcium carbonate")(CaCO_(3))+underset((C))(H_(2)O)` (iii) When excess of `CO_(2)` is passed, milkiness disappears due to the formation of soluble calcium bicarbonate (D). `underset((C))underset("Milkiness")(CaCO_(3))+CO_(2)+H_(2)Orarr underset((D))underset(("SOluble in"H_(2)O))underset("Calcium bicarbonate")(Ca(HCO_(3))_(2))` |
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| 262. |
The stability of peroxide and superoxide of alkali metals increase as we go down to group. Explain giving reason. |
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Answer» The stability of peroxide or superoxide increases as the size of metal ion increases i.e., `KO_(2) lt RbO_(2) lt CsO_(2)` ltbr. The reacivity of alkali metals towards oxygen to form different oxides is due to strong positive field around each alkali metal cation. `Li^(+)` is the smallest. It does not allow `O^(2-)` ion to react with `O_(2)` further. `Na^(+)` is larger than `Li`, its positive field is weaker than `Li^(+)`. It cannot prevent then conversion of `O^(2-)` into `O_(2)^(2-)`. The largest `K^(+),Rb^(+)` and `Cs^(+)` ions permit `O_(2)^(2-)` ion to react with `O_(2)` formign superoxide ion `O_(2)^(-)`. `underset("Oxide")(O_(2)^(2-))overset((1)/(2)O_(2))rarrunderset("Peroxide")(O^(2-))overset(O_(2))rarr underset("Superoxide")(2O_(2)^(-))` Futhermore, increased stability of the peroxide or superoxide with increase in the size of metal ion is due to the stabilisation of large anion by larger cations through lattice energy effect. |
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| 263. |
Match column I wht colun II and mark the appropriate choice. A. `Atoi,Btoii,Ctoiii`B. `Atoiii,Btoii,Ctoi`C. `Atoiii,Btoi,Ctoii`D. `Atoii,Btoiii,Ctoi` |
| Answer» Correct Answer - C | |
| 264. |
Why hydrated chlorides of Ca, Sr and Ba can be dehydrated by heating while those of Be and Mg suffer hydrolysis? |
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Answer» `CaCl_(2).6H_(2)O overset("Heat")toCaCl_(2)+6H_(2)O` `MgCl_(2).6H_(2)O overset("heat")toMgO+2HCl+5H_(2)O` `MgCl_(2).6H_(2)O` or `BeCl_(2).4H_(2)O` on heating suffer hydrolysis due to the high affinity towards hydrolysis. |
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| 265. |
The hydrated halides of ____ cannot be dehydrated on heating.A. Be and MgB. Mg and CaC. Ca and SrD. Sr and Ba |
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Answer» Correct Answer - A The hydrated chlorides, bromides and iodides of Ca, Sr, and Ba can be dehydrated by heating but those of Mg and Be suffer hydrolysis `CaCl_(2).6H_(2)Ooverset(Delta)toCaCl_(2)+6H_(2)O` `[Be(H_(2)O)_(4)]Cl_(2)overset(Delta)toBe(OH)_(2)+2HCl` |
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| 266. |
All the halides of group 2 elements form hydrates and are hygroscopic (absorb water vapor from the air). Which of the following is the most hydrated chloride ?A. `MgCI_(2)`B. `CaCI_(2)`C. `SrCI_(2)`D. `BaCI_(2)` |
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Answer» Correct Answer - A The tendency to form halide hydrates gradually decreases downthhe group due to the decrease of charge density of `M^(2+)` ion: `MgCl_(2).6H_(2)O,CaCl_(2).6H_(2)O,SrCl_(2).6H_(2)O, and BaCl_(2),2H_(2)O` |
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| 267. |
What is the trend of formation of hydrated halides among alkaline earth metals? |
| Answer» The tendency to form hydrate halides gradually decreases down the group. | |
| 268. |
Write the trend the trend of variation in atomic and ionic radii among the alkali metals. |
| Answer» On moving down the group atomic and ionic radii of alkali metals increases. | |
| 269. |
In the preparation of sodium carbonate `(Na_(2)CO_(3))` which of the following is used as raw material?A. SlakedlimeB. Lime stoneC. Quick limeD. Sodium hydroxide |
| Answer» Correct Answer - B | |
| 270. |
Statement-1: Pure NaCl is a diliquescent crystalline solid. Statement-2: `Na_(2)CO_(3)` is known as pearl ash. Statement-3: Sulphur disproportionates in NaOH.A. FFTB. TTFC. TFTD. FFF |
| Answer» Correct Answer - A | |
| 271. |
The formula of soda ash isA. `Na_(2)CO_(3)*10H_(2)O`B. `Na_(2)CO_(3)*2H_(2)O`C. `Na_(2)CO_(3)*H_(2)O`D. `Na_(2)CO_(3)` |
| Answer» Correct Answer - D | |
| 272. |
Which of the following is added to the table salt to prevetn it from absorbing moisture and to make it flow freely in the rainy season ?A. `Ca_(3)PO_(4)`B. `Ca(H_(2)PO_(4))_(2)`C. `Ca_(3)PO_(4) or Ca(H_(2)PO_(4))_(2)`D. None of these |
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Answer» Correct Answer - C These salts p[revent the moisture absorbing power of other components such as `MgCl_(2)` present in table salt and thus, keep table salt dry. Further both Ca and P are needed by our biological system and hence, do not cause any side-effect |
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| 273. |
Baking soda isA. `Na_(2)CO_(3)`B. `NaHCO_(3)`C. `Na_(2)SO_(4)`D. `NaNO_(3)` |
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Answer» Correct Answer - B Because on heating. It decomposes to generate bubbles of `CO_(2)` leavbing holes in cakes or pastries and making them light and fluffy. |
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| 274. |
In what ways lithium shows similarities to magnesium in its chemical behaviour? |
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Answer» Similarities between lithium and magnesium are as follows. (i) Both Li and Mg react slowly with cold water. (ii) The oxides of both Li and Mg are much less soluble in water and their hydroxides decompose at high temperature. `2LiOHoverset(heat)rarr Li_(2)O+H_(2)O` `Mg(OH)_(2)overset(heat)rarr MgO+H_(2)O` (iii) Both Li and Mg react with `N_(2)` to form nitrides. `6Li+N_(2)overset(heat)rarr2Li_(3)N` `3Mg+N_(2)overset(heat)rarrMg_(3)N_(2)` (iv) Neither Li nor Mg form peroxides or superoxides. (v) The carbonates of both are covalent in nature. Also, these decompose on heating. `Li_(2)CO_(3)overset(heat)rarrLi_(2)O+CO_(2)` `MgCO_(3)overset(heat)rarrMgO+CO_(2)` (vi) Li and Mg do not form solid bicarbonates. (vii) Both LiCl and `MgCl_(2)` are soluble in ethanol owing to their covalent nature. (viii) Both LiCl and `MgCl_(2)` are deliquescent in nature. They crystallize from aqueous solutions as hydrates, for example, `LiCl.2H_(2)O` and `MgCl_(2).8H_(2)O` |
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| 275. |
Assertion: The carbonate of lithium decomposes easily on heating. Reason: Lithium being very small in size polarises large carbonate ion leading to the formation of more stable `Li_(2)O and CO_(2)`.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 - A | |
| 276. |
Assertion (A) The carbonate of lithium decomposes easily on heating to form lithium oxide and `CO_(2)`. Reason (R) Lithium being very small in size polarises large carbonate ion leading to the formation of more stable `Li_(2)O` and `CO_(2)`.A. Both A and R are correct and R is the correct explanation of AB. Both A and R are correct but R is not the correct explanation of AC. Both A and R are not correctD. A is not correct but R is correct |
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Answer» Correct Answer - A The thermal stability of carbonates increases down the group. Hence `Li_(2)CO_(3)` is least stable. Due to small size of `Li^(+)`, strong polarising power distorts the electron cloud of `CO_(3)^(2-)` ion. High lattice energy of `Li_(2)O` than `Li_(2)CO_(3)` also favours the decomposition of `Li_(2)CO_(3)`. |
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| 277. |
Assertion: Lithium fluoride is most covalent in nature. Reason: Small anion an be easily distorted.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. |
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Answer» Correct Answer - D `Li^(+)` ion is very small in size and has high tendency to distort electron clud around the negative halide ion. Anion with large size and be easily distorted hence among halides, lithium iodide is the most covalent in nature. |
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| 278. |
Apart from water, alkali metals react with which kind of compounds? |
| Answer» Correct Answer - Proton donors. | |
| 279. |
What kind of chemical compounds are formed when alkali metal oxides react with water? |
| Answer» Correct Answer - Hydroxides. | |
| 280. |
Write two characteristics of halides of beryllium |
| Answer» Beryllium halides are covalent and soluble in oranic solvents. | |
| 281. |
Which of the following does not react with steam even at red heat ?A. BeB. MgC. CaD. Sr |
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Answer» Correct Answer - A Be is much less electropositive than other group 2 elements because its standard reduction potential `E^(@) (Be^(2+)//Be)` is much less negative than those for the rest of the group 2 elements and also for alkali metals. |
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| 282. |
Which of the following reactions is used to make anhydrous beryllium halides ?A. `2BeO+C CI_(4)overset(800^(@)C)to 2BeCl_(2)+CO_(2)`B. `BeO+C+CI_(2)overset(700^(@)C)hArr BeCl_(2)+CO`C. `(NH_(4))_(2)[BeF_(4)]overset(Delta)toBeF_(2)+2NH_(4)F`D. All of these |
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Answer» Correct Answer - D Anhydrous beryllium halides are best prepared by the best route for the preparation of `BeF_(2)`. The compound itself is made as follows `BeO+NH_(4)Fto(NH_(4))_(2)[BeF_(4)]` or `BeO+2NH_(3)+4HFto(NH_(4))_(2)[BeF_(4)]` Reaction with `C Cl_(4)` is a standard method for making anhydrous chlorides which cannot be obtained by dehydrating hydrates. |
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| 283. |
`BeCl_(2).4H_(2)Ooverset(Delta)to "P"` The product P isA. `BeCl_(2)`B. BeOC. `Be(OH)_(2)`D. BeOCI |
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Answer» Correct Answer - C Anhydrous beryllium halides cannot be obtained from materials made in aqueous solution because the hydrated ion `[Be(H_(2)O)_(4)]^(2+)` is formed e.g., `[Be(H_(2)O)_(4)]Cl_(2)` or `[Be(H_(2)O)_(4)]F_(2)`. Attempts to dehydrate result in hydrolysis: `[Be(H_(2)O)_(4)]Cl_(2)overset(Delta)toBe(OH)_(2)+2HCl` |
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| 284. |
Why lithium is kept wrapped in paraffin wax and not stored in kerosene oil ?A. It reacts with keroseneB. It floats to the surface of kerosene because of low densityC. It does not react with air and `H_(2)O`D. It is an inert metal |
| Answer» Correct Answer - B | |
| 285. |
Which of the following has the lowest melting point?A. BeB. MgC. CaD. Sr |
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Answer» Correct Answer - B In general, melting point decreases on moving down the group but the trend of melting point is not systematic on accound of the variation of crystal structure. `Be gt Ca gt Sr gt Ba gt Ra gt Mg` |
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| 286. |
One word answers are givenn for the following, Mark the example which is not correct.A. Alkali metals with lowest melting point- CsB. Alkaline earth metal with higher hydration ethalpy- `Ba^(2+)`C. Alkaline earth metal which imparts brick red colour to the flame-`Ca^(2+)`D. Oxide of alkaline earth metal which is amphoteric in nature -BeO |
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Answer» Correct Answer - B Hydration enthalpy decreases with increases in ionic size down the group. `Be^(2+) gt Mg^(2+) gt Ca^(2+) gt Sr^(2+) gt Ba^(2+)` |
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| 287. |
`NaOH+CO oversetr(200^(@)C)underset(5-10 atm)rarr A`. The product A is:A. HCOONaB. `Na_(2)CO_(3)`C. `NaHCO_(3)`D. `CO_(2)` |
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Answer» Correct Answer - A `NaOH(s)+CO(g)underset("pressure")overset(Delta)toHCOONa(s)` |
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| 288. |
Match the elements given in Column I with the properties mentioned in Column II. `{:(Column I,Column II),(A.Li,1."Insoluble sulphate"),(B.Na,2."Strongest monoacidic base"),(C.Ca,3."Most negative" E^(Theta) "value among alkali metals"),(D.Ba,4."Insoluble oxalate"),(,5.6s^(2)"outer electronic configuration"):}` |
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Answer» Correct Answer - A. `rarr(3)` B. `rarr(2)` C. `rarr(4)` D. `rarr(5)` A. `Li-`Most negative `E^(-)` among alkali metals [Due to very high hydration energy the resulting `E^(Theta)` is most negative] B. Na-Strongest monoacidic base [Alkalies are more acidic than alkaline earth metals. LiOh has covalent character]. C-Ca insoluble oxalate [Calcium oxalate is insoluble in water] D. Ba-Insoluble sulphate [Hydration energy decreases as size of cation increases]. `6s^(2)` outer electronic configuration. `._(56)Ba = 1s^(2),2s^(2),2p^(6),3s^(2),3p^(6),3d^(10),4s^(2),4p^(6),4d^(10),5s^(2),5p^(6),6s^(2)]` |
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| 289. |
Which among `Na,K,Cs` and `Li` forms most stable hydride?A. LiHB. KHC. NaHD. CsH |
| Answer» Correct Answer - A | |
| 290. |
The low solubility of LiF and that of CsI in water are respectively due to which of the properties of the alkali metal ions?A. Higher hydration enthalpy of `Li^(+)`, higher lattice enthalpy of `Cs^(+)`B. Smaller hydration enthalpy of `Li^(+)`, higher latttice enthalpy of `Cs^(+)`C. Smaller lattice enthalpy of `Li^(+)`, higher hydration enthalpy of `Cs^(+)`D. Higher lattice enthalpy of `Li^(+)`, smaller hydration enthalpy of `Cs^(+)`. |
| Answer» Correct Answer - D | |
| 291. |
All alkali halides are soluble in water except LiF. The low solublity of LiF in water is due to its (i)______ the low solubility of CsI is due to (ii)_____. LiF is soluble in (iii)_________ solvents.A. (i) low lattice enthalpy, (ii) large hydration enthalpy, (iii) polar solventsB. (i) high lattice enthalpy, (ii) smaller hydration enthalpy, (iii)-non-polar solventsC. (i) high hydration enthalpy, (ii)-high lattice enthalpy, (iii)- non-polar solventsD. (i)-smaller hydration enthalpy, (ii)-high lattice enthalpy, (iii)-polar solvents |
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Answer» Correct Answer - B The low solubility of LiF in water is due to its high lattice enthalpy whereas the low solubility of CsI is due to smaller hydration enthalpy of two large size ions. LiF is soluble in non-polar solvents like ethanol, acetone, etc. |
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| 292. |
Statement-1: Be imparts colour to the bunsen flame. Statement-2: Be has very high ionisation energy.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 - D | |
| 293. |
Which one among the following is the most basic?A. `Sr(OH_(2))`B. `Ba(OH)_(2)`C. `Ca(OH)_(2)`D. `Mg(OH)_(2)` |
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Answer» Correct Answer - D The basic strenght of the hydroxides of group 2 elements increases on moving down the group. |
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| 294. |
Which of the following alkaline earth metals imparts green color to the flame?A. RaB. BaC. SrD. Ca |
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Answer» Correct Answer - B Calcium, strontium, and barium impart characteristic brick red, crimson, and apple green colors to the flame, respectively. Radium also imparts crimson color. When these alkaline earth metals or their compounds are put into a flame, the electrons absorb energy and are excited to higher energy level.s when they drop back to the original state, energy is emitted in the form of visible light of particular frequency. The flame test for Ca, Sr and Ba is helpful is their detection in qualitative analysis and estimation. |
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| 295. |
Which of the following alkaline earth metals do not impart any color to the flame?A. Ca,SrB. Mg,CaC. Be,MgD. Sr,Ba |
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Answer» Correct Answer - B Relative to other group 2 elements, Be and Mg atoms are smaller in size. Thus, the electrons in Be and Mg are too strongly bound to get excited by flame. In other words, the energy required to excite electrons in Be and Mg atoms does not lie in the visible range. |
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| 296. |
Which pair of the following chlorides does not impart color to the flame ?A. `BeCI_(2) and SrCI_(2)`B. `MgCI_(2) and CaCI_(2)`C. `BeCI_(2) and MgCI_(2)`D. `CaCI_(2) and BaCI_(2)` |
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Answer» Correct Answer - C On account of relatively high ionization enthalpies, Be and Mg are not able to excite their `e^(-)` s in the visible range. Hence, their salts do not impart characteristic color to the flame. |
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| 297. |
Cement is essentially a finely powdered mixture of calcium silicates and aluminates along with small quantities of gypsum which sets into a hard stone-like mass when treated with water. Which of the following important ingredients present in Portland cement contributes to the maximum extent?A. Dicalcium silicateB. Tricalcium silcateC. Tricalcium aluminateD. Both (1) and (2) |
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Answer» Correct Answer - B Dicalcium silicate `(Ca_(2)SiO_(4))` is 26% trricalcium silicate `(Ca_(3)SiO_(5))` is 51% ad tricalcium aluminate `(Ca_(3)Al_(2)O_(6))` is 11% |
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| 298. |
Metal carbonates decompose on heating to give metal oxide and carbon dioxide. Which of the metal carbonates is most stable thermally?A. `MgCO_(3)`B. `CaCO_(3)`C. `SrCO_(3)`D. `BaCO_(3)` |
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Answer» Correct Answer - D `BaCO_(3)` is thermally most stable because of the small size of resulting oxide ion. With the increase in atomic number, the size of the metal ion, the stability of the metal ion decreases and hence that of carbonate increases (maximum in case of `BaCO_(3))`. Therefore, the increasing size of cation destabilizes the oxides and hence doesnot favour the decomposition of heavier alkaline earth metal carbonates like `BaCO_(3)` |
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| 299. |
Dead burnt plaster isA. `CaCO_(3)`B. `CaSO_(4).(1)/(2)H_(2)O`C. `CaSO_(4).2H_(2)O`D. `CaSO_(4)` |
| Answer» Correct Answer - D | |
| 300. |
Dead burnt plaster isA. `CaSO_(4)`B. `CaSO_(4)*(1)/(2)H_(2)O`C. `CaSO_(4)*H_(2)O`D. `CaSO_(4)*2H_(2)O` |
| Answer» Correct Answer - A | |