94420 + Interview Questions in Chemistry in Class 12

1.	Oxygen shows anomalous behaviour because
Answer» it SUPPORTS COMBUSTION. it is FOUND in the atmosphere. because of its LARGE size. because of its SMALL size. Answer :D

Discussion

2.	Oxygen plays a key role in the troposphere while ozone in the stratosphere . Explain.
Answer» Solution :All boilogical activities take place in the TROPOSPHERE for which oxygen is required . OZONE in the stratosphere absorbs the harsh UV RADIATION coming from the sun which OTHERWISE cause skin cancer, affect the CORNEA of the eye .

Discussion

3.	Oxygen will react with each of the following elements readily, except
Answer» P Na S Cl Answer :D

Discussion

4.	Oxygen orm acidic oxide with
Answer» Ca Na S K Answer :C

Discussion

5.	Oxygen on reaction with non-metals forms oxides , which are
Answer» basic oxides acidic oxides amphoteric oxides neutral oxides SOLUTION :Oxides of non-metals are usually acidic , e.g., `CO_(2), SO_(2), SO_(3)`….. `CO_(2) + H_(2)O to H_(2)CO_(3)` (CARBONIC ACID) `SO_(2) + H_(2)O to H_(2)SO_(3)` (Sulphurous acid)

Discussion

6.	Oxygen molecules is
Answer» Diamagnetic with no UNPAIRED electrons Diamagnetic witgh TWO unpaired electrons PARAMAGNETIC with two unpaired electrons Paramagnetic with no unpaired electrons ANSWER :C

Discussion

7.	Oxygen, necessary for life on earth was formed in atmosphere as a result of :
Answer» ERADICATION of ozone Photosynthesis Electric DISCHARGE on water None of the above Answer :B

Discussion

8.	Oxygen molecule shows:
Answer» PARAMAGNETISM Dimagnetism Ferro magnetism Ferri magnetism Answer :A

Discussion

9.	Oxygen molecule is:
Answer» Paramagnetic Diamagnetic Ferromagnetic Ferrimagnetic Answer :A

Discussion

10.	Oxygen molecule is .......... due to the presence of ...... unpaired electrons.
Answer» SOLUTION :PARAMAGNETIC ,TWO

Discussion

11.	Oxygen is the most electronegative element in the periodic table.
Answer» SOLUTION :Fluonne is the most clecituegulive ELEMENT in the pencuc table.

Discussion

12.	Oxygen is present in a one-litre flask at a pressure of 7.6 xx 10^(-10) mm Hg. Calculate the number of oxygen molecules in the flask at 0^(C).
Answer» <P> SOLUTION :`p = 7.7 XX 10^(-10)` ATM `= 0.01 xx 10^(-10)` atm (760 mm = 1 atm) `T = (0+273) = 273 K` We have, pV = nRT `0.01 xx 10^(-10) xx 1 = n xx 0.0821 xx 273, therefore n = (10^(-12))/(0.0821 xx 273)` `therefore` no. of oxygen molecules = mole `xx` Av. const. `= (10^(-12))/(0.0821 xx 273) xx 6.022 xx 10^(23)` `= 2.68 xx 10^(10)`.

Discussion

13.	Oxygen is paramagnetic. The unpaired electrons are present in:
Answer» Antibonding orbitals Bonding orbitals p-orbitals f-orbitals Answer :A

Discussion

14.	Oxygen is prepared commercially from:
Answer» SODIUM and WATER Electrolysis of water `KClO_3 and MnO_2` `HNO_3` ANSWER :B

Discussion

15.	Oxygen molecule is having even number of electrons but is paramagnetic. Why?
Answer» SOLUTION :DIAMAGNETIC

Discussion

16.	Oxygen is ozonised until the partial pressures of both gases are same. What percentage of oxygen is ozonised?
Answer» `40%` `60%` `50%` `25%` Solution :`2O_(3) HARR 3O_(2)`

Discussion

17.	Oxygen is not evolved when:
Answer» ZnO is heated with NaOH `NH_(4)NO_(3)` is heated `Na_(2)O_(2)` reacts with water `KClO_(3)` is heated Solution :`O_(2)`is evolved when `2Na_(2)O_(2)+2H_(2)O to 4NaOH +O_(2), 2KClO_(3) overset(DELTA)to 2KCl +3O_(2)`

Discussion

18.	Oxygen is obtained from bleaching powder by:
Answer» The ACTION of DILUTE acid The action of alkali Heating it with lime Heating it with COBALT salt Answer :A

Discussion

19.	Oxygen is more electronegative than sulphur, yet H_2S is acidic while H_2O is neutral. This is because:
Answer» Water is a HIGHLY associated compound H-S bond is weaker than H-O bond `H_2S` is a gas while `H_2O` is a liquid The molecular WEIGHT of `H_2S` is more than that of `H_2O` ANSWER :B

Discussion

20.	Oxygen is more electronegative than sulphur, yet H_(2)S is acidic while H_(2)O is neutral. This is because
Answer» WATER is HIGHLY associatedcompound H-S bond is WEAKER than H-O bond `H_(2)S` is a gas while `H_(2)O` is a liquid The MOLECULAR weight of `H_(2)S` is more Answer :B

Discussion

21.	Oxygen is manufactured by fractional distillation of:
Answer» `H_2O` `H_2O_2` `Na_2O_2` LIQUID air Answer :D

Discussion

22.	Oxygen is liberated from water using
Answer» P Na `F_2` `I_2` ANSWER :C

Discussion

23.	In photosynthesis , oxygen is liberated due to
Answer» <P>P NA `F_(2)` `I_(2)` ANSWER :C

Discussion

24.	Oxygen is gas but sulphur is solid because:
Answer» Oxygen is composed of discrete molecules while SULPHUR is polymeric Molecular WEIGHT of sulphur is much higher than that of oxygen Oxygen is a stronger oxidising agent than sulphur Boiling point of sulphur is much higher than that of oxygen Answer :A

Discussion

25.	Oxygen is divalent, whereas sulphur exhibits valency of 2,4 and 6 due to:
Answer» S is BIGGER atom Ionisation POTENTIAL of SULPHUR is more S being less ELECTRONEGATIVE than O Presence of d-orbitals in S Answer :D

Discussion

26.	Oxygen is -------.
Answer» Diamagnetic PARAMAGNETIC Ferromagnetic Nonmagnetic Solution :Paramagnetic

Discussion

27.	Oxygen is denser than air so it is collected over
Answer» `H_(2)O` ETHANOL Mercury Kerosene OIL ANSWER :A

Discussion

28.	Oxygen is denser than air, so it is collected over
Answer» water spirit mercury kerosene Answer :A

Discussion

29.	Oxygen is available in plenty in the air fuels do not burn by themselves at room temperature. Explain.
Answer» Solution :Activation energy for COMBUSTION REACTIONS of fuels is very high at ROOM temperature therefore they do not BURN by themselves.

Discussion

30.	Oxygen is carried away from lungs by blood mainly because of the presence of :
Answer» GLOBULIN COLLAGEN HEME Glutathion. ANSWER :C

Discussion

31.	Oxygen is available in plenty in air yet fuels do not burn by themselves at room temprature.Explain.
Answer» Solution :The ACTIVATION ENERGY for comnustion REACTIONS of FUEL is high at room TEMPERATURE therefore they do not burn by themselves.

Discussion

32.	Oxygen is available in plenty in air yet fuels do not burn by themselves at room temperature. Explain.
Answer» SOLUTION :The ACTIVATION ENERGY for the combustion of fuels is very high at room temperature. Therefore, they do not BURN by themselves.

Discussion

33.	Oxygen is always divalent while sulphur can form 2, 4 and 6 bonds because
Answer» Oxygen is more electronegative than sulphur Sulphur was vacant d-orbitals while oxygen does not Sulphur has LARGE atomic radius than oxygen SULPHURE is more electronegative than oxygen. ANSWER :B

Discussion

34.	Oxygen is always divalent whereas sulphur can from 2,4 and 6 bonds. This is because
Answer» oxygen is more ELECTRONEGATIVE than sulphur sulphur CONTAINS d-orbitals whereas oxygen does not sulphur has LARGER atomic radius than oxygen sulphur is more electronegative than oxygen. Solution :Sulphur contains d-orbitals and therefore, can expand its octet forming 2,4 and 6 bonds whereas oxygen does not contain d-orditals and is always divalent.

Discussion

35.	Oxygen is absorbed by molten Ag, which is evolved on cooling and the silver particles are scattered, the phenomenon is known as:
Answer» SILVERING of mirror Spitting of silver Frosting of silver Hairing of silver Answer :B

Discussion

36.	Oxygen is a gas while others are solids and S,Se,Te exists as staggered rings in normal conditions. How many number of atoms are present in one ring?
Answer»

Discussion

37.	Oxygen is a gas while other are solids and S, Se, Te exist as staggered rings in normal condition. Howmany number of atoms are present in one ring
Answer» SOLUTION :S, Se, TE are octa-atomic PUCKERED ring structures.

Discussion

38.	Oxygen is a gas but sulphur a solid. Explain.
Answer» SOLUTION :Oxygen being SMALLEST in size is capable of FORMING `ppi-ppi` bond and exists as `O=O`. (`O_(2)` molecule) WHITE sulphur being larged in size is not ABLE to form `ppi-ppi` bond.

Discussion

39.	Oxygen is a gas, but other elements of group 16 are solids at room temperature. Why?
Answer» Solution :Oxygen exists as isolated diatomic molecules. Between atoms of oxygen molecule the attractionsare STRONG, but inter MOLECULAR attractions are very weak. Hence oxygen is a gas. Other elements of group 16, have complex states. The TENDENCY to form multiple bonds between identical atoms decreases with an increase in atomic weight. BONDING ability between many atoms of same element increases. Molecular complexity and van der Waals forces increase. Hence, they are solids.

Discussion

40.	Oxygen in milligrams required for five days in one litre of water at 20^@for the microorganisms to metabolise organic waste is called _______.
Answer» ANSWER :A::B::C::D

Discussion

41.	Out of O and S which has higher negative electron gain enthalpy and why ?
Answer» SOLUTION :DUE to the COMPACT NATURE of OXYGEN.

Discussion

42.	Oxygen gas can be prepared from solid KMnO_4 by:
Answer» DISSOLVING the SOLID in DIL.HCl Dissolving the solid in dil.`H_2SO_4` TREATING the solid with `H_2` gas Strongly HEATING the solid Answer :D

Discussion

43.	Oxygen forms only fluorides, but other chalcogens form different halides. Why?
Answer» Solution :The binary compound of oxygen and fluorine is called fluoride, but not oxide. `OF_(2) and O_(2)F_(2)` are the fluorides of oxygen, with oxidation STATE of .O., respectively `+2 and +1`. The binary compounds of oxygen with other HALOGENS are known, eg. `Cl_(2)O_(6),Cl_(2)O_(7),BrO_(3),I_(2)O_(5), I_(4)O_(9)`, etc. But they are called oxides of halogens.

Discussion

44.	Oxygen exhibits positive oxidation state with:
Answer» F Br Cl I Answer :A

Discussion

45.	Oxygen exhibits positive oxidation state in
Answer» `CO` `F_(2)O` `NO` `N_(2)O` SOLUTION :In `F_(2)O`, the OXIDATION STATE of OXYGEN is `+2`.

Discussion

46.	Oxygen does not show positive oxidation state (except on O_2F_2 and OF_2) due to
Answer» presence of unpaired ELECTRONS High electronegativity small SIZE INERT pair effect Solution :ABSENCE of d ORBITAL. Electronic configuration `1s^2 2s^2 2p^4`

Discussion

47.	Oxygen does not react with
Answer» P Na S Cl ANSWER :D

Discussion

48.	Oxygen does not react with :
Answer» Cl S Na P Solution :Oxygen does not react with `4P+4O_(2) overset(Delta)to P_(4)O_(8)` [It is OBTAINED by HEATING phosphorus in a limitedsupply of air at 563K. `P_(4)+SO_(2) to P_(4)O_(10)` (EXCESS of air)

Discussion

49.	Oxygen contains 90% of O^(16) and 10 % " of " O^(18). Its atomic mass is
Answer» `17.4` `16.2` `16.5` 17 Solution :OXYGEN has 90% `O^(16) and 10 % O^(18)` Atomic mass = `[(90)/(100) xx 16 + (10)/(100) xx 18]` `= (1440 + 180)/(100) = (1620)/(100) = 16.2`

Discussion

50.	Oxygen cannot exhibit higher oxidation states due to
Answer» SMALL SIZE more electronegativity LESS density lack of vacent d orbitals ANSWER :D

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Oxygen shows anomalous behaviour because

Oxygen plays a key role in the troposphere while ozone in the stratosphere . Explain.

Oxygen will react with each of the following elements readily, except

Oxygen orm acidic oxide with

Oxygen on reaction with non-metals forms oxides , which are

Oxygen molecules is

Oxygen, necessary for life on earth was formed in atmosphere as a result of :

Oxygen molecule shows:

Oxygen molecule is:

Oxygen molecule is .......... due to the presence of ...... unpaired electrons.

Oxygen is the most electronegative element in the periodic table.

Oxygen is present in a one-litre flask at a pressure of 7.6 xx 10^(-10) mm Hg. Calculate the number of oxygen molecules in the flask at 0^(C).

Oxygen is paramagnetic. The unpaired electrons are present in:

Oxygen is prepared commercially from:

Oxygen molecule is having even number of electrons but is paramagnetic. Why?

Oxygen is ozonised until the partial pressures of both gases are same. What percentage of oxygen is ozonised?

Oxygen is not evolved when:

Oxygen is obtained from bleaching powder by:

Oxygen is more electronegative than sulphur, yet H_2S is acidic while H_2O is neutral. This is because:

Oxygen is more electronegative than sulphur, yet H_(2)S is acidic while H_(2)O is neutral. This is because

Oxygen is manufactured by fractional distillation of:

Oxygen is liberated from water using

In photosynthesis , oxygen is liberated due to

Oxygen is gas but sulphur is solid because:

Oxygen is divalent, whereas sulphur exhibits valency of 2,4 and 6 due to:

Oxygen is -------.

Oxygen is denser than air so it is collected over

Oxygen is denser than air, so it is collected over

Oxygen is available in plenty in the air fuels do not burn by themselves at room temperature. Explain.

Oxygen is carried away from lungs by blood mainly because of the presence of :

Oxygen is available in plenty in air yet fuels do not burn by themselves at room temprature.Explain.

Oxygen is available in plenty in air yet fuels do not burn by themselves at room temperature. Explain.

Oxygen is always divalent while sulphur can form 2, 4 and 6 bonds because

Oxygen is always divalent whereas sulphur can from 2,4 and 6 bonds. This is because

Oxygen is absorbed by molten Ag, which is evolved on cooling and the silver particles are scattered, the phenomenon is known as:

Oxygen is a gas while others are solids and S,Se,Te exists as staggered rings in normal conditions. How many number of atoms are present in one ring?

Oxygen is a gas while other are solids and S, Se, Te exist as staggered rings in normal condition. Howmany number of atoms are present in one ring

Oxygen is a gas but sulphur a solid. Explain.

Oxygen is a gas, but other elements of group 16 are solids at room temperature. Why?

Oxygen in milligrams required for five days in one litre of water at 20^@for the microorganisms to metabolise organic waste is called _______.

Out of O and S which has higher negative electron gain enthalpy and why ?

Oxygen gas can be prepared from solid KMnO_4 by:

Oxygen forms only fluorides, but other chalcogens form different halides. Why?

Oxygen exhibits positive oxidation state with:

Oxygen exhibits positive oxidation state in

Oxygen does not show positive oxidation state (except on O_2F_2 and OF_2) due to

Oxygen does not react with

Oxygen does not react with :

Oxygen contains 90% of O^(16) and 10 % " of " O^(18). Its atomic mass is

Oxygen cannot exhibit higher oxidation states due to