52671 + Interview Questions in Chemistry in Class 11

1.	Alk aline earth metal (A), belongs to 3rd period reacts with oxygen and nitrogen to form compound (B) and (C) respectively. It undergo metal displacement reaction with AgNO_3 solution to form compound (D).
Answer» Solution :(i) An alkaline earth (A) metal belongs to third period is magnesium (Mg) (ii) Magnesium REACTS with oxygen to form magnesium oxide (MgO) (B) `2Mg +O_(2)tounderset(Magnesium oxide)(2MgO_(2))` (iii) Magnesium reacts with NITROGEN to form magnesium nitride `Mg_(3)N_(2)(C)` `3Mg+N_(2)O_(2)tounderset("Magnesium nitride")(Mg_(3)O)` (iv) Magnesium UNDERGOES metal displacement reaction with `AgNO_(3)` solution to form magnesium nitrate `Mg(NO_(3))_(2) (D)` `Mg+2AgNO_(3) tounderset("Magnesium nitrate") (Mg(NO_(3))_(2) +)2AG`

Discussion

2.	Alkali metals when exposed to air tarnish quickly due to the
Answer» FORMATION of their HYDROXIDES Formation of their CARBONATES Formation of their OXIDES All the above ANSWER :D

Discussion

3.	Alkali metals used in photoelectric cells
Answer» `LI` `Li, NA` `Li, Na, K` `K, CS` ANSWER :D

Discussion

4.	Alkali metalstaenishin dryairbecause______.
Answer» theyreactwithoxygento formcorrespodingoxides theyreactwithnitrogen toformcorrespondingnitides theyhydrogentoform correspondinghydrides theyreactwithhalogensto formcorrespondinghalides ANSWER :A

Discussion

5.	Alkali metals readily react with oxyacids forming corresponding salts (like M_(2)CO_(3), MHCO_(3), MNO_(3), M_(2)SO_(4) etc) with evolution of hydrogen. They also dissolve in liquid NH3 but without the evolution of hydrogen. The colour of its dilute solution is blue when it is heated and concentrated, then its colour becomes bronze Among the carbonates of alkali metals which one has highest stability
Answer» `Cs_(2)CO_(3)` `Rb_(2)CO_(3)` `K_(2)CO_(3)` `Na_(2)CO_(3)` Solution :In alkali metl carbonaties from top to bottom stability increases due to decreasing of crystal LATTICE ENERGY of their corresponding OXIDES

Discussion

6.	Alkali metals react with water vigorously to form hydroxides and dihydrogen . Which of the following alkali metal reacts with water least vigorously ?
Answer» Li Na K Cs Solution :Both m.p. and heat of the reaction of alkali metals with `H_(2)O` decreases down the group from Li to Cs . Although the heat of reaction of Li is thehighest but DUE to its high melting POINT , EVEN the heat is not sufficient to melt the METAL thereby exposing greater surface to water for reaction . as a result , Li has the least reactivity by the reactivity increases as the m.p. of the alkali metals decrease down the group from Li to Cs .

Discussion

7.	Alkali metals react with water vigorously to form hydroxides and dihydrogen. Which of the following alkali metals reacts with water least vigorously?
Answer» Li Na K CS Solution :Li has very high ENTHALPY of hydration, therefore the reaction between Li and water is HIGHLY exothermic but the energy evolved is consumed in fusion, vaporisation, and ionisation as a result reaction with water proceeds SLOWLY.

Discussion

8.	Alkali metals react with water vigorously to form hydroxides and dihydrogen. Which of the following alkali metals reacts with water least vigorously
Answer» LI Na K Cs Solution :DUE to high melting pointeven thought Li has high HEAT of hydration it is not sufficientto melt which exposes greatest surface to water for a reaction `THEREFORE`Li has least REACTIVITY

Discussion

9.	Alkali metalsreactoxygento form_______
Answer» NITROGENGAS oxygengas CHLORINEGAS HYDROGENGAS ANSWER :D

Discussion

10.	Alkalimetals(otherthanlithium) formamidesof thegeneralformula ______.
Answer» MNH `MNH_(2)` `M_(2) NH` `M_(3)N` Answer :B

Discussion

11.	Alkali metals on reaction with enough amount of oxygen can form...
Answer» SUPER oxide Oxide Monoxide Peroxide Answer :D

Discussion

12.	Alkali metals never found in free state in nature. Why?
Answer» Solution :The loosely HELD "s" ELECTRON in the outermost shell of these elements make them electropositive METALS. They readily lose electron to give monovalent M ions. HEN never found in free state in nature.

Discussion

13.	Alkali metals loseelectronsin _______.
Answer» <P>s-ORBITALS p- orbitals d-orbitals f-orbitals ANSWER :A

Discussion

14.	Alkali metals impart colour to bunsen flame due to
Answer» low ionization ENERGIES low melting POINTS thier softness the presence of ONE electron in the outer most SHELL Answer :A

Discussion

15.	Alkali metals have negative reduction potential and hence they behave as
Answer» Oxidising agents Lewis base reducing agents electrolytes. SOLUTION :(C ) Alkali METALS have high negative REDUCTION POTENTIAL i.e., they can easily lose one electron. Hence they behave as reducing agents.

Discussion

16.	Alkali metals have low melting and boiling point. Density of alkali metals is very low. Give reason
Answer» Solution :LT is DUE to weak metallic BONDS and large atomic SIZE.

Discussion

17.	Alkali metals give colour in Bunsen flame due to
Answer» LOW IONISATION POTENTIAL low m.p. softness one ELECTRON in the OUTERMOST orbit. Solution : low ionisation potential

Discussion

18.	Alkali metals exhibit high chemical reactivity Give reason.
Answer» Solution :(i) Alkali metals exhibit high chemical reactivity because of their low ionization enhalphy and their larger SIZE (ii) The reactivity of alkali metals increases from Li to CS, since the value of ionization energy decreases down the group (from Li to Cs) (iii) All alkali metals are highly reactive TOWARDS the more ELECTRONEGATIVE elements such as oxygen and HALOGENS.

Discussion

19.	Alkali metals are usually stored in hydrocarbon solvents to protect them from air and moisture but lithium cannot . Why ?
Answer» SOLUTION :Lithium cannot be STORED in KEROSENE oil since it floatsover kerosene and other hydrocarbon solvents because of its very low density . Therefore , lithium is usually kept WRAPPED in paraffin wax.

Discussion

20.	Alkali metals contain
Answer» 7 VALENCE electrons 1 valence ELECTRON 4 valence electrons 2 valence electrons. Solution :1 valence electron

Discussion

21.	Alkali metals are strongly electropositive or metalic in character. Why ?
Answer» SOLUTION :Alkali metals are strongly electropositve because of their low IONIZATION enthalpies, these metals have a strong tendency to LOSE their valence electrons.

Discussion

22.	Alkali metals are soft and have low melting point and boiling point due to
Answer» INTER atomic BONDS are weak Inter atomic bonds are strong Low ionisation potential Smaller atomic SIZE ANSWER :A

Discussion

23.	Alkali metals are stored under oil. Give reason.
Answer» Solution :ALKALI METALS are so REACTIVE and they have to be STORED under OIL. Because when they are kept in air, they will burn immediately.

Discussion

24.	Alkali metals are stored in...
Answer» Water Kerosene Alcohol Acid Answer :B

Discussion

25.	Alkali metals are so named because
Answer» of their LARGE atomic sizes of their OXIDES give strong bases in water of their high reactivity in air of their colours IMPARTED in BUNSEN flame Answer :B

Discussion

26.	Alkali metals are paramagentic but their salts are diamagnetic . Explain .
Answer» Solution :Alkali metals contain one unpaired electron `(ns^(1))` and hence are paramagnetic . However , during SALT formation , this unpaired electron is transferred to the non-metallic atom forming its anion . As a result , salt has PAIRED ELECTRONS both in the CATION as well as in the anion and hence alkali metal salts are diamagnetic in NATURE .

Discussion

27.	Alkali metals are kept under ........because they are highly........and get .....when exposed to air.
Answer» SOLUTION :KEROSENE, REACTIVE, TARNISHED

Discussion

28.	Alkali metals are highly reactive due to....
Answer» SMALLER SIZE and low IONIZATION ENERGY. Higher size and low ionization energy. Smaller size and high ionization energy. Higher size and high ionization energy. Answer :B

Discussion

29.	Alkali metals are good conductors of electricity. Why?
Answer» Solution :Alkali metals have low ionization energy. Hence they SHOW METALLIC CHARACTER. They are good conductors of electricity DUE to the presence of mobile valence ELECTRONS.

Discussion

30.	Alkali metals are good
Answer» OXIDISING AGENTS REDUCING agent Bleaching agents dehydrating agent Solution :Due to low I.E they acts as GOOD reducing agents

Discussion

31.	Alkali metals are characterised by
Answer» GOOD CONDUCTOR of heat and electricity High oxidation potential High MELTING point Solubility in liquid ammonia. Solution :ALKALI metals have low melting points.

Discussion

32.	Alkali metal iodide(s) aqueous solution(s) of which can dissolve I_(2) to form MI_(3) is (are)
Answer» K Na Rb Cs. Solution :SODIUM cannot FORM POLYHALIDE of the form `MI_(3)`

Discussion

33.	Alkali metal oxides are soluble in
Answer» Carbon tetrachloride Benzene Water Kerosene oil. SOLUTION :DUE to high HEAT of hydration which can OVERCOME the lattice ENERGY.

Discussion

34.	Alkali metal hydrides are strong reducing agents. Prove this statement.
Answer» Solution :The decrease in IONIZATION ENTHALPY down the group permits easy availability of electrons to forms `H^(+)` ions. So, the hydrides BEHAVE as reducing agent. Their reducing nature INCREASES down the group

Discussion

35.	Alkali metal halides can be prepared by the reaction of aquesous hydrohalic acid with
Answer» Alkali METAL oxide Alkalimetal hydroxide Alkali metal CARBONATE Any of the above ANSWER :D

Discussion

36.	Alkali metal element have low melting point and boiling point, because...
Answer» WEAK metallic bond. strong metallic bond. weak COVALENT bond. strong ATTRACTION towards valence electron. Answer :A

Discussion

37.	Alkali metal carbonates are stable but carbonates of alkaline earth metals decompose on heating to liberate CO_(2) Why?
Answer» Solution :Polarising power of ALKALINE earth metal cations is more than that of alkali metal cations because of small size and HIGH charge. Alkaline earth metal cations polarise a large `CO_(3)^(2-)` ion leading to the formation of more stable oxide (MO) and liberate `CO_(2)` gas. `MCO_(3)rarrMO+CO_(2)UARR`

Discussion

38.	Alkali metal are __________ reactive.
Answer» highly lower very low less than matels Answer :A

Discussion

39.	Alkali elements exhibit an oxidation state of __________
Answer» `+1` `+2` `+3` `+4` ANSWER :A

Discussion

40.	Alkali and alkaline earth metals along with hydrogen and helium constitute s-block elements . They have low ionization enthalpies and hence exhibit characteristic flame colouration . They have highly negative electrode potentials and hence are strong reducing agents . Their solutions in liquid ammonia are conducting and also act as strong reducing agents than hydrogen , they are usually prepared by electrolysis of their fused chlorides . Their oxides are basic and the basic strength increases down the group . The solubility of carbonates and sulphates of alkali and alkaline earth metals show opposite trends . The carbonates of alkaline earth metals and lithium carbonate decompose on heating while the carbonates of other alkali metals do not decompose on heating . The bicarbonates of both alkali and alkaline earth metals on heating give carbonates . Which of the following process is used in the extractive metallurgy of magnesium ?
Answer» fused salt electrolysis self REDUCTION AQUEOUS solution electrolysis thermite reduction ANSWER :A

Discussion

41.	Alkali and alkaline earth metals along with hydrogen and helium constitute s-block elements . They have low ionization enthalpies and hence exhibit characteristic flame colouration . They have highly negative electrode potentials and hence are strong reducing agents . Their solutions in liquid ammonia are conducting and also act as strong reducing agents than hydrogen , they are usually prepared by electrolysis of their fused chlorides . Their oxides are basic and the basic strength increases down the group . The solubility of carbonates and sulphates of alkali and alkaline earth metals show opposite trends . The carbonates of alkaline earth metals and lithium carbonate decompose on heating while the carbonates of other alkali metals do not decompose on heating . The bicarbonates of both alkali and alkaline earth metals on heating give carbonates . The metal that produces red-violed colour in the non-luminous flame is
Answer» BA RB MG K ANSWER :B

Discussion

42.	Alkali and alkaline earth metals along with hydrogen and helium constitute s-block elements . They have low ionization enthalpies and hence exhibit characteristic flame colouration . They have highly negative electrode potentials and hence are strong reducing agents . Their solutions in liquid ammonia are conducting and also act as strong reducing agents than hydrogen , they are usually prepared by electrolysis of their fused chlorides . Their oxides are basic and the basic strength increases down the group . The solubility of carbonates and sulphates of alkali and alkaline earth metals show opposite trends . The carbonates of alkaline earth metals and lithium carbonate decompose on heating while the carbonates of other alkali metals do not decompose on heating . The bicarbonates of both alkali and alkaline earth metals on heating give carbonates . The compound insoluble in acetic acid is
Answer» calcium oxide calcium carbonate calcium oxalate calcium HYDROXIDE . Solution :`CaO , CaCO_(3)` and `Ca(OH)_(2)` are all bases and hence must DISSOLVE in ACETIC acid to form calcium acetate . Only calcium oxalate does not dissolve in `CH_(3)COOH` .

Discussion

43.	Alkali and alkaline earth metals cannot be obtained by chemical reduction method . Explain .
Answer» SOLUTION :SINCE they are themselves stronger REDUCING agents thanmajority of the COMMON reducing agents used .

Discussion

44.	Alkali and alkaline earth metals along with hydrogen and helium constitute s-block elements . They have low ionization enthalpies and hence exhibit characteristic flame colouration . They have highly negative electrode potentials and hence are strong reducing agents . Their solutions in liquid ammonia are conducting and also act as strong reducing agents than hydrogen , they are usually prepared by electrolysis of their fused chlorides . Their oxides are basic and the basic strength increases down the group . The solubility of carbonates and sulphates of alkali and alkaline earth metals show opposite trends . The carbonates of alkaline earth metals and lithium carbonate decompose on heating while the carbonates of other alkali metals do not decompose on heating . The bicarbonates of both alkali and alkaline earth metals on heating give carbonates . Which of the following are arranged in increasing order of solubilities ?
Answer» `CaCO_(3) lt KHCO_(3) lt NaHCO_(3)` `NaHCO_(3) lt KHCO_(3) lt CaCO_(3)` `KHCO_(3) lt NaHCO_(3) lt CaCO_(3)` `CaCO_(3) lt NaHCO_(3) lt KHCO_(3)`. Solution :The solubility of bicarbonates of ALKALI metals increases down the GROUP . But ALKALINE earth metal carbonates are insoluble in `H_(2)O` , i.e., option (d) is CORRECT .

Discussion

45.	Alkali and alkaline earth metals along with hydrogen and helium constitute s-block elements . They have low ionization enthalpies and hence exhibit characteristic flame colouration . They have highly negative electrode potentials and hence are strong reducing agents . Their solutions in liquid ammonia are conducting and also act as strong reducing agents than hydrogen , they are usually prepared by electrolysis of their fused chlorides . Their oxides are basic and the basic strength increases down the group . The solubility of carbonates and sulphates of alkali and alkaline earth metals show opposite trends . The carbonates of alkaline earth metals and lithium carbonate decompose on heating while the carbonates of other alkali metals do not decompose on heating . The bicarbonates of both alkali and alkaline earth metals on heating give carbonates . The basic character of the oxides , MgO , SrO , K_(2)O , NiO and Cs_(2)O increases in the order :
Answer» `MGO gt Sr O gt K_(2)O gt NIO gt Cs_(2)` `Cs_(2) lt K_(2)O lt MgO lt SrO lt NiO` `NiO lt MgO lt SrO lt K_(2)O lt Cs_(2)O` `K_(2)O ltNiO lt MgO lt SrO lt Cs_(2)` Solution :Alkali metal OXIDES are most basic followed by alkaline earth metal oxides while transition metal oxides are LEAST basic . Amongst alkali and alkaline earth metal oxides , basicity increases down the group . Thus , `Cs_(2)O` is more basic than `K_(2)O` and `SrO` is more basic than MgO . therefore , the overall order is `: NiO lt MgO lt SrO lt K_(2)O lt Cs_(2)O`.

Discussion

46.	Aliphatic saturated hydrocarbon can give
Answer» Addition reaction ELIMINATION reaction Both (a) and (B) SUBSTITUTION reaction Solution :Saturated HYDROCARBONS substitution reaction is possible as all are SINGLE bonds

Discussion

47.	Aliphatic nulcleophilic substitution reactions take places either by ______ or _______ mechanism .
Answer» `S_(N)""^(1) , S_(N)""^(2)` `E_(1), E_(2) ` `ADDITION , substitution Replacement , CONDENSE Solution :N/A

Discussion

48.	Alicyclic compounds are :
Answer» AROMATIC compounds Aliphatic CYCLIC compounds Heterocyclic compounds None of these Answer :B

Discussion

49.	AlH_(3) is an example for
Answer» INTERSTITIAL hydride ELECTRON RICH hydride Ionic hydride Electron deficient hydride ANSWER :D

Discussion

50.	AlF_(3) soluble in HF only in presence of KF. It is due to the formation of
Answer» `K_(3)[AlF_(3)H_(3)]` `K_(3)[AlF_(6)]` `AlH_(3)` `Kl[AlF_(3)H]` Solution :Anhydrous`HF` is a covalentcompoundand is stronglyH-bounded . THEREFORE, it does not give `F^(-)`ions andhence `AlF_(3)`does notcompoundcontains `F^(-)` ions. Therefore, it combineswith `AlF_(3)` to form SOLUBLE COMPLEX, `K_(3)[AlF_(6)]` `AlF_(3) + 3KF rarr K_(3)[AlF_(6)]`

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Alk aline earth metal (A), belongs to 3rd period reacts with oxygen and nitrogen to form compound (B) and (C) respectively. It undergo metal displacement reaction with AgNO_3 solution to form compound (D).

Alkali metals when exposed to air tarnish quickly due to the

Alkali metals used in photoelectric cells

Alkali metalstaenishin dryairbecause______.

Alkali metals react with water vigorously to form hydroxides and dihydrogen . Which of the following alkali metal reacts with water least vigorously ?

Alkali metals react with water vigorously to form hydroxides and dihydrogen. Which of the following alkali metals reacts with water least vigorously?

Alkali metals react with water vigorously to form hydroxides and dihydrogen. Which of the following alkali metals reacts with water least vigorously

Alkali metalsreactoxygento form_______

Alkalimetals(otherthanlithium) formamidesof thegeneralformula ______.

Alkali metals on reaction with enough amount of oxygen can form...

Alkali metals never found in free state in nature. Why?

Alkali metals loseelectronsin _______.

Alkali metals impart colour to bunsen flame due to

Alkali metals have negative reduction potential and hence they behave as

Alkali metals have low melting and boiling point. Density of alkali metals is very low. Give reason

Alkali metals give colour in Bunsen flame due to

Alkali metals exhibit high chemical reactivity Give reason.

Alkali metals are usually stored in hydrocarbon solvents to protect them from air and moisture but lithium cannot . Why ?

Alkali metals contain

Alkali metals are strongly electropositive or metalic in character. Why ?

Alkali metals are soft and have low melting point and boiling point due to

Alkali metals are stored under oil. Give reason.

Alkali metals are stored in...

Alkali metals are so named because

Alkali metals are paramagentic but their salts are diamagnetic . Explain .

Alkali metals are kept under ........because they are highly........and get .....when exposed to air.

Alkali metals are highly reactive due to....

Alkali metals are good conductors of electricity. Why?

Alkali metals are good

Alkali metals are characterised by

Alkali metal iodide(s) aqueous solution(s) of which can dissolve I_(2) to form MI_(3) is (are)

Alkali metal oxides are soluble in

Alkali metal hydrides are strong reducing agents. Prove this statement.

Alkali metal halides can be prepared by the reaction of aquesous hydrohalic acid with

Alkali metal element have low melting point and boiling point, because...

Alkali metal carbonates are stable but carbonates of alkaline earth metals decompose on heating to liberate CO_(2) Why?

Alkali metal are __________ reactive.

Alkali elements exhibit an oxidation state of __________

Alkali and alkaline earth metals cannot be obtained by chemical reduction method . Explain .

Aliphatic saturated hydrocarbon can give

Aliphatic nulcleophilic substitution reactions take places either by ______ or _______ mechanism .

Alicyclic compounds are :

AlH_(3) is an example for

AlF_(3) soluble in HF only in presence of KF. It is due to the formation of

Aliphatic nulcleophilic substitution reactions take places either by or _ mechanism .