52671 + Interview Questions in Chemistry in Class 11

1.	Sodium nitrate decomposes above 800^(@)C to give
Answer» `N_(2)` `O_(2)` `NO_(2)` `Na_(2)O` SOLUTION :`NaNO_(3)` DECOMPOSES above `800^(@)C` to give `O_(2)` `2KNO_(3)(s)overset(800^(@)C)rarr2KNO_(2)(s)+O_(2)(g)`

Discussion

2.	Sodium metal vaporises on heating and the vapour will have diatomic molecular of sodium (Na_(2)). What type of bonding is presetn in these moleculas ? Justify your answer .
Answer» SOLUTION :Covalent bonds are present in `Na_(2)` . This can be explained on the basis of molecular orbital theory . Electronic configuration of `""_(11)Na = 1s^(2) 2S^(2) 2p^(6) 3S^(1)` . The 3s atomic ORBITALS of the two sodium atoms combine to form `sigma _(3s) and sigma _(3s)^(**)`molecular orbitals . The two electrons entre into `sigma_(3s)` . Hence, BOND order = 1 . Thus , the two sodiium atoms are linked by a single covalent bond .

Discussion

3.	Sodium metal vapprises on heating and the vapours have diatomic molecules of sodium (Na_(2)). what type of bonding is present in these moleceles ?
Answer» ANSWER :A

Discussion

4.	Sodium metal on dissolution in liquid ammonia gives a deep blue solution due to the formation of ..........
Answer» sodamide ammoniated electrons sodium ion-ammonia complex sodium-ammonia complex Solution :`Na overset(Liq.NH_(3))to UNDERSET("Deep blue colour")([Na(NH_(3))_(N)]^(2+)) +underset("Ammoniated ELECTRON")(2[E(NH_(3))_(n)]^(-))`

Discussion

5.	Sodium metal itself is used as
Answer» OXIDISING agent DEHYDRATING agents reducing agent bleaching agent ANSWER :C

Discussion

6.	Sodium metal is stored in ....... to avoid contact with air and water.
Answer» Alcohol Kerosene Ether Water Answer :B

Discussion

7.	Sodium metal is extracted by the electrolysis of fused chloride but potassium metal cannot be obtained by electrolysis of fused potassium chloride . Why so ?
Answer» SOLUTION :Since K METAL is more soluble in KCL than NA metal is soluble in NaCl .

Discussion

8.	Sodium metal preserved under kerosine. This is to prevent
Answer» volatility of METAL REACTIVITY in air reactivity with CHLORINE METALLIC luster Answer :B

Discussion

9.	Sodium metal crystallizes in a body -centred cubic lattice with a unit cell edge of 4.29 Å. The radius of sodium metal is approximately
Answer» 5.72 Å 0.93 Å 1.86 Å 3.22 Å Solution :For BCC, `r=sqrt3/4 a =1.732/4xx4.29 Å=1.86 Å`

Discussion

10.	Sodium metal crystallizes in a body -centred cubic lattice with a unit cell edge of4. 29 Å. The radius of sodium metal is approximately.
Answer» 5.72 Å 0.93 Å 1.86 Å 3.22 Å Solution :ForBCC, `R = sqrt3/4 a == 1.732/4 XX 4.29 Å= 1.86 Å`

Discussion

11.	Sodium metal crystallises in body centred cubic lattice with the cell edge , 4.29 Å. What is the radius of sodium atom? What is the length of the body diagonal of the unit cell ?
Answer» Solution :For BODY centred cubic lattice, the RELATIONSHIP between the cell EDGE (a) and the radius of the atom is `r=sqrt3/4a=1.732/4xx4.29`=1.86 Å Length of the body DIAGONAL =4r =4 x 1.86 Å=7.44 Å

Discussion

12.	Sodium lamp emits yellow light of wavelength 5800 Å the wave number of the light is
Answer» `1.72xx10^(6)//m` `17.2xx10^(8)//m` `5.17xx10^(14)//s` `17.2xx10^(7)//m` Solution :WAVE NUMBER `=1/lambda` `=1/(5800xx10^(-10)m)=1.724xx10^(6)//m`

Discussion

13.	Sodium-lead alloy is used in the preparation of which is used as an ............... compound to improve the quality of petrol
Answer» SOLUTION : TETRA ETHYL lead and ANTI KNOCK

Discussion

14.	Sodium is made by the electrolysis of a molten mixture of about 40% NaCl and 60% CaCl_2 because(a)Ca^(2+)ion can reduce NaCl to Na(b)CaCl_2 helps in conduction of electricity(c)this mixture has a lower melting point than NaCl(d)Ca^(2+) can displace Na fromNaCl.
Answer» `Ca^(2+)`ion can REDUCE NaCl to Na `CaCl_2` HELPS in conduction of electricity this mixture has a lower MELTING POINT than NaCl `Ca^(2+)` can displace Na from`NaCl`. Solution :this mixture has a lower melting point than NaCl

Discussion

15.	Sodium is strongly metallic, while chlorine is strongly non-metallic - explain.
Answer» ANSWER :If sodium loses an electron it attains NOBLE GAS CONFIGURATION and if CHLORINE gains an electron, it attains noble gas configuration

Discussion

16.	Sodium is stored under kerosene. Give reason.
Answer» Solution :Because sodium metals is highly REACTIVE and combies with oxygen, moisture and `CO_(2)` from present in AIR FORMING `Na_(2)O, NAOH` and `Na_(2)CO_(3)` etc,

Discussion

17.	sodium is stored in
Answer» alcohol water KEROSENE none of these Solution :kerosene

Discussion

18.	Sodium ion is isoelectronic with……..atom
Answer» `MG^(2+)` `Al^(3+)` `Ne` `N^(3-)` SOLUTION :`Mg^(+2) , Al^(+3) , N^(-3)` are iso electronic ions

Discussion

19.	Sodium in liquid ammonia is called mixed conductor. Comment.
Answer» SOLUTION :Sodium metal as wella as sodium cation. Both are present in a solution of sodium in ammonia. It is a mixture of ELECTRONIC and ELECTROLYTIC conductor.

Discussion

20.	Sodium hydroxide on reaction with CO_(2)produces .......
Answer» Solution :SODIUM CARBONATE `(Na_(2)CO_(3))`

Discussion

21.	Sodium hydroxide is also known as......
Answer» SOLUTION :CAUSTIC SODA

Discussion

22.	Sodium hydroxide is a deliquescent in nature. Why?
Answer» SOLUTION :NaOH is a DELIQUESCENT solid because it absorbs moisture from the AIR and dissolves in that moisture.

Discussion

23.	Sodium hydrogen carbonate is produce on passing of which gas through the washing soda?
Answer» `O_(2)` `H_(2)` CO `CO_(2)` SOLUTION :`Na_(2)CO_(3)+H_(2)O+CO_(2) to 2NaHCO_(3)`

Discussion

24.	Sodium hydrogen carbonate is known as ......
Answer» SOLUTION :BAKING SODA

Discussion

25.	Sodium hexametaphosphate is known as ……… at commerically.
Answer» calgon complex leuco caglon Answer :A

Discussion

26.	Sodium has a bcc structure with nearest neighbour neighbour distance 365.9 pm. Calculate its density (Atomic mass of sodium = 23)
Answer» Solution :For the BCC, structure, nearst NEIGHBOUR distance (d)is related to the edge (a) as ` d= sqrt3/2 a` or ` a= 2/sqrt3 d = 2 / 1.732 xx 365.9 = 422.5` pm. For bcc stucture, Z =2 For sodiumM= 23 , ` p = ( Z xx M)/ (a^(3) xx N_(0)) = (2xx23 "g mol"^(-1))/((422.5xx10^(-10) cm)^(3)xx(6.02xx 10^(23)"mol"^(-1)))= 1.51 "g/cm"^(3)`

Discussion

27.	Sodium has a bcc structure with nearest neighbour distance 365.9 pm. Calculate its density (Atomic mass of sodium =23)
Answer» Solution :For the BCC structure , nearest NEIGHBOUR distance (d) is RELATED to the edge (a) as `d=sqrt3/2 a` or `a=2/sqrt3 d =2/1.732xx365.9` =422.5 pm For bcc structure, Z=2 For sodium , M=23 `THEREFORE RHO =(ZxxM)/(a^3xxN_0)=(2xx23 g mol^(-1))/((422.5xx10^(-10)cm)^3xx(6.02xx10^23 mol^(-1))=1.51 g//cm^3`

Discussion

28.	The violet flame shown by potassium in bunsen flame is due to jumping of the electron from
Answer» SOLUTION :YELLOW, PALE, VIOLET

Discussion

29.	Sodium fusion extract, obtained from aniline, a treatment with iron (II) sulphate and H_(2)SO_(4) in presence of air gives a prussion blue precipitate. The blue colour is due to the formation of:
Answer» `Fe_(4)[FE(CN)_(6)]_(3)` `Fe_(3)[Fe(CN)_(6)]_(2)` `Fe_(4)[Fe(CN)_(6)]_(2)` `Fe_(3)[Fe(CN)_(6)]_(3)` Answer :A

Discussion

30.	Sodium fusion extract, obtained from aniline, on treatment with iron (II) sulphate and H_(2)SO_(4) in presence of air gives a prussian blue precipitate. Hence, the blue colour is due to the formation of
Answer» `Fe_(4)[Fe(CN)_(6)]_(3)` `Fe_(3)[Fe(CN)_(6)]_(2)` `Fe_(4)[Fe(CN)_(6)]_(2)` `Fe_(3)[Fe(CN)_(6)]_(3)` Answer :A

Discussion

31.	Sodium fusion extract of an organic compound gives blood red colour with FeSO_(4)//Conc. H_(2)SO_(4) on heating. Fresh extract of the same compound gives black precipitate when mixed with (CH_(3)COO)_(2)Pb and with yellow precipitate when treated with AgNO_(3) solution. Then the organic compound may be
Answer» `C_6H_12NCl` `C_6H_12NI` `C_6H_12NSI` `C_6H_12SI` ANSWER :C

Discussion

32.	Sodium forms a crystalline ionic solid with dihydrogen . The solid is non-volatile and non-conducting in nature. It reacts violently with water to produce dihydrogen gas. Write the formula of this compound and its reaction with water. What will happen on electrolysis of the melt of this solid.
Answer» Solution :Sodium reacts with dihydrogen to form sodium hydride which is a CRYSTALLINE ionic solid. `2Na+H_(2) to 2Na^(+) H^(-)` It reacts with `H_(2)O` to produce `H_(2)` gas `2NaH+2H_(2)O to 2NAOH + 2H_(2)` Although `Na^(+)H^(-)` does not conduct electricity in the solid state but the ELECTROLYSIS of its melt PRODUCES `H_(2)` at the anode and Na at the cathode `Na^(+)H^(-)(l) overset("Electrolysis")to overset("At cathode")(2Na(l))+ overset("At anode")(H_(2)(g))`

Discussion

33.	Sodium forms a crystalline ionic solid with dihydrogen. The solid is non-volatile and non conducting in nature. It reacts violently with water to produce dihydrogen gas. Write the formula of this compound and its reaction with water. What will happen on electrolysis of the melt of this solid.
Answer» Solution :Sodium reacts with dihydrogen to FORM sodium HYDRIDE which is a crystalline ionic solid. `2NA+H_2 to 2Na^(+) H^-` It reacts with `H_2O` to produce to `H_2` gas. `2NaH+2H_2O to 2NaOH + 2H_2` ALTHOUGH `Na^+H` does not conduct ELECTRICITY in the solid state but the electrolysis of its melt produces `H_2` at the anode and Na at the cathode. `Na^(+)H^(-) overset"Electrolysis"to underset"At cathode"(2Na_((l))) + underset"At Anode"(H_(2(g)))`

Discussion

34.	Sodium fire in the laboratory should not be extinguished by pouring water . Why ?
Answer» Solution :The reaction of sodium with `H_(2)O` is so exothermic that the `H_(2)` produced CATCHES fire . `2 Na + 2 H_(2)O to 2 NaOH + H_(2)` As a result , the fire spreads rather than being extinguished . Therefore , `H_(2)O` should not be USED for EXTINGUISHING sodium fire . instead pyrene `(C Cl_(4))` should be used . When `C Cl_(4)` is sprinkled over fire , it being volatile (b.p. 350 K) immediately forms vapours . These vapours being non-inflammable and heavy , SURROUND the fire . As a result , supply of air is cut off and the fire gets extinguished .

Discussion

35.	Sodium crystallizes in a bcc unit cell. Calculate the approximate number of unit cells in 92 g of sodium (Atomic mass of Na = 23)
Answer» Solution :BCC has 2 ATOMS PER unit CELL.

Discussion

36.	Sodium crystallises in the cubic lattice and the edge of the unit cell is 430 pm. Calculate the number of atoms in a unit cell. [Atomic mass of Na=23.0 amu, Density of sodium = 0.9623 "g cm"^(-3), N_A=6.023xx10^23 "mol"^(-1)]
Answer» ANSWER :2, i.e., BCC

Discussion

37.	Sodium chloride, NaCl, usually crystallizes in a face-centred cubic lattice. How many ions are in contact with any single Na^(+)ion?
Answer» 4 6 8 1 Solution :In NaCl having FCC structure, each `Na^(+)`ion is surrounded by SIX `Cl^(-)`ion at the CORNERS of a regular OCTAHEDRON.

Discussion

38.	Sodium chloride is soluble in water but insoluble in benzene or hexane. Explain in the observation.
Answer» Solution :SODIUM chloride is an ionic solid and water is a polar SOLVENT. Water molecules attract `Na^(+) and Cl^(-)` ions by their negative and positive poles RESPECTIVELY. As a result, theions get detached from the crystal lattice and undergo solvation with the evolution of solvation enegy. in this case, SINCE the solvation ENERGY is greater than lattice energy. NaCl dissolves in water. on the other hand, benzene and hexane are non-polar organic solvents and they cannot solvate `Na^(+) and Cl^(-)` ions. hence, sodium chloride is insoluble in benzene or hexane.

Discussion

39.	Sodium chloride crystallises into F.C.C lattice with Na+ occupying corner of a cube and the centre of each face, whereas Cl^(-) is occupies the centre of each edge and centre of the cube. The r_c //r_a value for NaCl is 0.53 and coordination number is 6. In NaCl unit cell, the edge length is
Answer» `2r_c+2r_a` `r_c +r_a` `(r_c + r_a)/(2)` `SQRT(3) (r_c +r_a)` ANSWER :A

Discussion

40.	Sodium chloride crystallises into F.C.C lattice with Na occupying corner of a cube and the centre of each face, whereas Cl^(-) is occupies the centre of each edge and centre of the cube. The r_c //r_a value for NaCl is 0.53 and coordination number is 6. If all the face centred ions along one of the axis are removed, the stoichiometry of the resulting solid is
Answer» `NACL `Na_2 CL` `Na_3 Cl_2` `Na_3 Cl_4` ANSWER :D

Discussion

41.	Sodium chloride crystallises into F.C.C lattice with Nat occupying corner of a cube and the centre of each face, whereas Cl^(-) is occupies the centre of each edge and centre of the cube. The r_c //r_a value for NaCl is 0.53 and coordination number is 6,6. In NaCl crystal lattice each sodium ion is surrounded by — number of chloride ions in ---- fashion
Answer» 8, TETRAHEDRAL 6, octahedral 8, square planar 6, DISTORTED octahedron ANSWER :B

Discussion

42.	Sodium chloride crystallises into F.C.C lattice with Na occupying corner of a cube and the centre of each face, whereas Cl^(-) is occupies the centre of each edge and centre of the cube. The r_c //r_a value for NaCl is 0.53 and coordination number is 6,6. If all the ions present in one plane that is passing through the centre are removed, the formula of the resulting unit cell is
Answer» `NACL` `Na_2 Cl_3` `Na_3 Cl_2` `NaCl_2` ANSWER :A

Discussion

43.	Sodium carbonate (Na_(2)CO_(3)0can be obtained by heating sodium hydrogen carbonate,NaHCO_(3) 2NaHCO_(3)(s) rarr Na_(2)CO_(3)(s)+H_(2)O(g) + CO_(2)(g) Calculate the temperatureabove which NaHCO_(3) decomposes to form products at 1 bar . Given Delta_(f)H^(@) ( kJ mol^(-1)):NaHCO_(3)(s) = =- 947.7 , Na_(2)CO_(3)(s) = - 1130 .9, H_(2)O(g)= - 241.8 , CO_(2)(g) = - 393.5 S^(@) (JK^(-1) mol^(-1)) : NaHCO_(3)(s) = 102.1 , Na_(2)CO_(3) (s)=136.0, H_(2)O(g) = 188.8, CO_(2)(g) 213.7
Answer» Solution : `Delta_(r)H^(@) = ( -1130.9) + ( -241.8) + ( -393.5)- 2 xx ( -947.7 )= 129.2 KJ mol^(-1)` `Delta_(r)S^(@) = ( 136.0 +188.8 +213.7) - 2( 102.1) = 334.3 JK^(-1) mol^(-1)` `Delta_(r)G^(@)= Delta_(r)H^(@)-TDelta_(r)S^(@)`, At equilibrium , `DELTAG^(@)= 0, T - ( Delta_(r)H^(@))/( Delta_(r)S^(@))= ( 129200)/( 334.3) = 386.5K` Thus, above 386.5 K , `Delta_(r)G^(@)` will be negative and the reactionwill be spontaneous.

Discussion

44.	Sodium carbonate is manufactured by Solvay process. The products those are recycled are
Answer» `CO_(2)` and NH `CO_(2)` and `NH_(4)C_(1)` NaCl and CaO `CaCl_(2)` and CaO Answer :A

Discussion

45.	Sodium carbonate is soluble in water because
Answer» High LATTICE ENTHALPY LOW lattice enthalpy Low MOLECULAR weight High molecular weight ANSWER :B

Discussion

46.	Sodium carbonate is prepared by …….and its formula is ……. .
Answer» Solution :Solvay AMMONIA PROCESS , `Na_(2) CO_(3) . 10 H_(2)O`

Discussion

47.	Sodium carbonate is generally prepared by a process called ammonia soda process as follows : The above process cannot be used for the manufacturing of K_(2)CO_(3) because
Answer» `KHCO_(3)` is soluble in water and doe not percipitate in carbonating water `KHCO_(3)` is less soluble than `NaHCO_(3)` POTASSIUM is LIGHTER than sodium Sodium reacted with water in carbonating tower Answer :A

Discussion

48.	Sodium carbonate is manufactured by Solvay process. The products that are recycled are
Answer» `CO_2and NH_3` `CO_2 and NH_4Cl` `NACL, CAO` `CaCl_2, CO`. SOLUTION :`CO_2and NH_3`

Discussion

49.	Sodium carbonate is highly soluble in water, but magnesium carbonate is less soluble. Why?
Answer» Solution :Cation of group IA,`M^(+)` has one unit CHARGE, while that of IIA, `M^(2+)` has two UNITS charge. The GREATER the charge, the greater is the lattice energy. In the case of magnesium carbonate, lattice energy dominates hydration energy. HENCE, it is less soluble.

Discussion

50.	Sodium carbonate is generally prepared by a process called ammonia soda process as follows : Which of the following is by-product in the above process?
Answer» `NH_(4)CL` `CaCl_(2)` `NH_(4)OH` CaO Answer :B

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Sodium nitrate decomposes above 800^(@)C to give

Sodium metal vaporises on heating and the vapour will have diatomic molecular of sodium (Na_(2)). What type of bonding is presetn in these moleculas ? Justify your answer .

Sodium metal vapprises on heating and the vapours have diatomic molecules of sodium (Na_(2)). what type of bonding is present in these moleceles ?

Sodium metal on dissolution in liquid ammonia gives a deep blue solution due to the formation of ..........

Sodium metal itself is used as

Sodium metal is stored in ....... to avoid contact with air and water.

Sodium metal is extracted by the electrolysis of fused chloride but potassium metal cannot be obtained by electrolysis of fused potassium chloride . Why so ?

Sodium metal preserved under kerosine. This is to prevent

Sodium metal crystallizes in a body -centred cubic lattice with a unit cell edge of 4.29 Å. The radius of sodium metal is approximately

Sodium metal crystallizes in a body -centred cubic lattice with a unit cell edge of4. 29 Å. The radius of sodium metal is approximately.

Sodium metal crystallises in body centred cubic lattice with the cell edge , 4.29 Å. What is the radius of sodium atom? What is the length of the body diagonal of the unit cell ?

Sodium lamp emits yellow light of wavelength 5800 Å the wave number of the light is

Sodium-lead alloy is used in the preparation of which is used as an ............... compound to improve the quality of petrol

Sodium is made by the electrolysis of a molten mixture of about 40% NaCl and 60% CaCl_2 because(a)Ca^(2+)ion can reduce NaCl to Na(b)CaCl_2 helps in conduction of electricity(c)this mixture has a lower melting point than NaCl(d)Ca^(2+) can displace Na fromNaCl.

Sodium is strongly metallic, while chlorine is strongly non-metallic - explain.

Sodium is stored under kerosene. Give reason.

sodium is stored in

Sodium ion is isoelectronic with……..atom

Sodium in liquid ammonia is called mixed conductor. Comment.

Sodium hydroxide on reaction with CO_(2)produces .......

Sodium hydroxide is also known as......

Sodium hydroxide is a deliquescent in nature. Why?

Sodium hydrogen carbonate is produce on passing of which gas through the washing soda?

Sodium hydrogen carbonate is known as ......

Sodium hexametaphosphate is known as ……… at commerically.

Sodium has a bcc structure with nearest neighbour neighbour distance 365.9 pm. Calculate its density (Atomic mass of sodium = 23)

Sodium has a bcc structure with nearest neighbour distance 365.9 pm. Calculate its density (Atomic mass of sodium =23)

The violet flame shown by potassium in bunsen flame is due to jumping of the electron from

Sodium fusion extract, obtained from aniline, a treatment with iron (II) sulphate and H_(2)SO_(4) in presence of air gives a prussion blue precipitate. The blue colour is due to the formation of:

Sodium fusion extract, obtained from aniline, on treatment with iron (II) sulphate and H_(2)SO_(4) in presence of air gives a prussian blue precipitate. Hence, the blue colour is due to the formation of

Sodium forms a crystalline ionic solid with dihydrogen . The solid is non-volatile and non-conducting in nature. It reacts violently with water to produce dihydrogen gas. Write the formula of this compound and its reaction with water. What will happen on electrolysis of the melt of this solid.

Sodium forms a crystalline ionic solid with dihydrogen. The solid is non-volatile and non conducting in nature. It reacts violently with water to produce dihydrogen gas. Write the formula of this compound and its reaction with water. What will happen on electrolysis of the melt of this solid.

Sodium fire in the laboratory should not be extinguished by pouring water . Why ?

Sodium crystallizes in a bcc unit cell. Calculate the approximate number of unit cells in 92 g of sodium (Atomic mass of Na = 23)

Sodium crystallises in the cubic lattice and the edge of the unit cell is 430 pm. Calculate the number of atoms in a unit cell. [Atomic mass of Na=23.0 amu, Density of sodium = 0.9623 "g cm"^(-3), N_A=6.023xx10^23 "mol"^(-1)]

Sodium chloride, NaCl, usually crystallizes in a face-centred cubic lattice. How many ions are in contact with any single Na^(+)ion?

Sodium chloride is soluble in water but insoluble in benzene or hexane. Explain in the observation.

Sodium chloride crystallises into F.C.C lattice with Na+ occupying corner of a cube and the centre of each face, whereas Cl^(-) is occupies the centre of each edge and centre of the cube. The r_c //r_a value for NaCl is 0.53 and coordination number is 6. In NaCl unit cell, the edge length is

Sodium carbonate is manufactured by Solvay process. The products those are recycled are

Sodium carbonate is soluble in water because

Sodium carbonate is prepared by …….and its formula is ……. .

Sodium carbonate is generally prepared by a process called ammonia soda process as follows : The above process cannot be used for the manufacturing of K_(2)CO_(3) because

Sodium carbonate is manufactured by Solvay process. The products that are recycled are

Sodium carbonate is highly soluble in water, but magnesium carbonate is less soluble. Why?

Sodium carbonate is generally prepared by a process called ammonia soda process as follows : Which of the following is by-product in the above process?