Solved Example: p-Block Element | Chemistry for JEE Main & Advanced PDF Download

 Page 1


JEE Solved Example on P block Element 
JEE Mains 
Q1: ?? ?? ????
?? ?
?
(?? )+????
?? ; is 
(A) Dehydration reaction 
(B) Oxidation reaction 
(C) Disproportionation reaction 
(D) Dephosphorylation reaction 
Ans: (C) H
3
PO
2
?
?
(X)+PH
3
; 
Disproportionation reaction 
 
Q2: Which of the following species is not a pseudohalide? 
(A) ?????? -
 
(B) ???????? -
 
(C) ?????? -
 
(D) ?? ?? -
 
Ans: (B) (b) Pseudohalogen molecules: (meaning"fake" halogens) are inorganic molecules of the 
general forms Ps-Ps or Ps-X, where Ps is a pseudohalogen group such as cyanide, cyanate, 
thiocyanate and others, and ?? is a "true" halogen. 
 
Q3:  First compound of inert gases was prepared by scientist Neil Barthlete in 1962. This compound 
is 
(A) ?????????? ?? 
(B) ?????? ?? 
(C) ?????? ?? 
(D) ???????? ?? 
Ans: (A) Fact. 
 
Q4:  Boron forms ????
?? type of halides. The correct increasing order of Lewis-acid strength of these 
halides is 
(A) ????
?? >?????? ?? >??????
?? >????
?? 
(B) ????
?? >??????
?? >?????? ?? >????
?? 
(C) ????
?? >????
?? >?????? ?? >??????
?? 
(D) ????
?? >?????? ?? >????
?? >??????
?? 
Ans: (B) (b) Depends on the sizes of the halogens 
 
 
Page 2


JEE Solved Example on P block Element 
JEE Mains 
Q1: ?? ?? ????
?? ?
?
(?? )+????
?? ; is 
(A) Dehydration reaction 
(B) Oxidation reaction 
(C) Disproportionation reaction 
(D) Dephosphorylation reaction 
Ans: (C) H
3
PO
2
?
?
(X)+PH
3
; 
Disproportionation reaction 
 
Q2: Which of the following species is not a pseudohalide? 
(A) ?????? -
 
(B) ???????? -
 
(C) ?????? -
 
(D) ?? ?? -
 
Ans: (B) (b) Pseudohalogen molecules: (meaning"fake" halogens) are inorganic molecules of the 
general forms Ps-Ps or Ps-X, where Ps is a pseudohalogen group such as cyanide, cyanate, 
thiocyanate and others, and ?? is a "true" halogen. 
 
Q3:  First compound of inert gases was prepared by scientist Neil Barthlete in 1962. This compound 
is 
(A) ?????????? ?? 
(B) ?????? ?? 
(C) ?????? ?? 
(D) ???????? ?? 
Ans: (A) Fact. 
 
Q4:  Boron forms ????
?? type of halides. The correct increasing order of Lewis-acid strength of these 
halides is 
(A) ????
?? >?????? ?? >??????
?? >????
?? 
(B) ????
?? >??????
?? >?????? ?? >????
?? 
(C) ????
?? >????
?? >?????? ?? >??????
?? 
(D) ????
?? >?????? ?? >????
?? >??????
?? 
Ans: (B) (b) Depends on the sizes of the halogens 
 
 
Q5: The compound (?????? ?? )
?? ?? is 
(A) Pyramidal and more basic than (????
?? )
?? ?? 
(B) Planar and less basic than (????
?? )
?? ?? 
(C) Pyramidal and less basic than (????
?? )
?? ?? 
(D) Planar and more basic than (????
?? )
?? ?? 
Ans: (B) (b) It has a lone pair in 2p orbital which is transferred to the empty d-orbital of Si atom 
resulting ???? -???? bonding. 
 
Q6: In a molecule of phosphorus (?? ) oxide, there are 
(A) ???? -?? ,?????? -?? and ???? =?? bonds. 
(B) ?????? -?? and ???? =?? bonds 
(C) ???? -?? and ???? =?? bonds 
(D) ???? -?? ,?????? -?? and ???? =?? bonds 
Ans: (B) 
 
Q7:  When oxalic acid reacts with conc. ?? ?? ????
?? ?? two gases produced are neutral and acidic in 
nature respectively. Potassium hydroxide absorbs one of the two gases. 
The product formed during this absorption and the gas which absorbed are respectively. 
(A) ?? ?? ????
?? and ????
?? 
(B) ???????? ?? and ????
?? 
(C) ?? ?? ????
?? and ???? 
(D) ???????? ?? and ???? 
Ans: (A) 
H
2
C
2
O
4
+H
2
SO
4
?H
2
O+CO+CO
2
KOH+CO
2
?K
2
CO
3
+H
2
O
 
 
Q8: Which of the following is the correct order of acidic strength? 
(A) ????
?? ?? ?? >????
?? >?? ?? ?? ????
 
(B) ????
?? >?? ?? ?? ?? >????
?? 
(C) ????
?? ?? >?????? >????
?? ?? ?? 
(D) ?? ?? ?? >?????? >?????? 
Ans: (A) Acidic strengths increases as electronegativity of atom increases So, Cl
2
O
7
>SO
2
>P
4
O
10
 
Page 3


JEE Solved Example on P block Element 
JEE Mains 
Q1: ?? ?? ????
?? ?
?
(?? )+????
?? ; is 
(A) Dehydration reaction 
(B) Oxidation reaction 
(C) Disproportionation reaction 
(D) Dephosphorylation reaction 
Ans: (C) H
3
PO
2
?
?
(X)+PH
3
; 
Disproportionation reaction 
 
Q2: Which of the following species is not a pseudohalide? 
(A) ?????? -
 
(B) ???????? -
 
(C) ?????? -
 
(D) ?? ?? -
 
Ans: (B) (b) Pseudohalogen molecules: (meaning"fake" halogens) are inorganic molecules of the 
general forms Ps-Ps or Ps-X, where Ps is a pseudohalogen group such as cyanide, cyanate, 
thiocyanate and others, and ?? is a "true" halogen. 
 
Q3:  First compound of inert gases was prepared by scientist Neil Barthlete in 1962. This compound 
is 
(A) ?????????? ?? 
(B) ?????? ?? 
(C) ?????? ?? 
(D) ???????? ?? 
Ans: (A) Fact. 
 
Q4:  Boron forms ????
?? type of halides. The correct increasing order of Lewis-acid strength of these 
halides is 
(A) ????
?? >?????? ?? >??????
?? >????
?? 
(B) ????
?? >??????
?? >?????? ?? >????
?? 
(C) ????
?? >????
?? >?????? ?? >??????
?? 
(D) ????
?? >?????? ?? >????
?? >??????
?? 
Ans: (B) (b) Depends on the sizes of the halogens 
 
 
Q5: The compound (?????? ?? )
?? ?? is 
(A) Pyramidal and more basic than (????
?? )
?? ?? 
(B) Planar and less basic than (????
?? )
?? ?? 
(C) Pyramidal and less basic than (????
?? )
?? ?? 
(D) Planar and more basic than (????
?? )
?? ?? 
Ans: (B) (b) It has a lone pair in 2p orbital which is transferred to the empty d-orbital of Si atom 
resulting ???? -???? bonding. 
 
Q6: In a molecule of phosphorus (?? ) oxide, there are 
(A) ???? -?? ,?????? -?? and ???? =?? bonds. 
(B) ?????? -?? and ???? =?? bonds 
(C) ???? -?? and ???? =?? bonds 
(D) ???? -?? ,?????? -?? and ???? =?? bonds 
Ans: (B) 
 
Q7:  When oxalic acid reacts with conc. ?? ?? ????
?? ?? two gases produced are neutral and acidic in 
nature respectively. Potassium hydroxide absorbs one of the two gases. 
The product formed during this absorption and the gas which absorbed are respectively. 
(A) ?? ?? ????
?? and ????
?? 
(B) ???????? ?? and ????
?? 
(C) ?? ?? ????
?? and ???? 
(D) ???????? ?? and ???? 
Ans: (A) 
H
2
C
2
O
4
+H
2
SO
4
?H
2
O+CO+CO
2
KOH+CO
2
?K
2
CO
3
+H
2
O
 
 
Q8: Which of the following is the correct order of acidic strength? 
(A) ????
?? ?? ?? >????
?? >?? ?? ?? ????
 
(B) ????
?? >?? ?? ?? ?? >????
?? 
(C) ????
?? ?? >?????? >????
?? ?? ?? 
(D) ?? ?? ?? >?????? >?????? 
Ans: (A) Acidic strengths increases as electronegativity of atom increases So, Cl
2
O
7
>SO
2
>P
4
O
10
 
 
Q9:  ???? +?? ?? ??????? ?? ?
?
 ?? Compound (A) is used as a/an 
(A) Fertilizer 
(B) Dehydrating agent 
(C) Oxidizing agent 
(D) Reducing agent 
Ans: (A) CaC
2
+N
2
? CaCN
2
?  
Calcium cyanamide 
+C 
 
Q10:  A gas which exists in three allotropic forms ?? ,?? , and ?? is 
(A) ????
?? 
(B) ????
?? 
(C) ????
?? 
(D) ????
?? 
Ans: (B) Fact. 
 
Q11:  When an inorganic compound reacts with ????
?? in aqueous medium, produces (A). (A) on 
reaction with ????
?? ????
?? , gives compound (B) which with sulphur, gives a substance (?? ) used in 
photography. Compound ?? is 
(A) ????
?? ?? 
(B) ????
?? ?? ?? ?? ?? 
(C) ????
?? ????
?? 
(D) ????
?? ?? ?? ?? ?? 
Ans: (D) Self explanatory 
 
Q12: Borax is actually made of two tetrahedral and two triangular units joined together and should 
be written as: ????
?? [ ?? ?? ?? ?? (???? )
?? ]·?? ?? ?? ?? . Consider the following statements about borax: 
(a) Each boron atom has four B-O bonds 
(b) Each boron atom has three B-O bonds 
(c) Two boron atoms have four B-O bonds while other two have three B-O bonds. 
(d) Each boron atom has one -???? groups 
Select correct statement(s) 
(A) a, b 
(B) b, c 
(C) c, d 
(D) a, c 
Ans: C 
Page 4


JEE Solved Example on P block Element 
JEE Mains 
Q1: ?? ?? ????
?? ?
?
(?? )+????
?? ; is 
(A) Dehydration reaction 
(B) Oxidation reaction 
(C) Disproportionation reaction 
(D) Dephosphorylation reaction 
Ans: (C) H
3
PO
2
?
?
(X)+PH
3
; 
Disproportionation reaction 
 
Q2: Which of the following species is not a pseudohalide? 
(A) ?????? -
 
(B) ???????? -
 
(C) ?????? -
 
(D) ?? ?? -
 
Ans: (B) (b) Pseudohalogen molecules: (meaning"fake" halogens) are inorganic molecules of the 
general forms Ps-Ps or Ps-X, where Ps is a pseudohalogen group such as cyanide, cyanate, 
thiocyanate and others, and ?? is a "true" halogen. 
 
Q3:  First compound of inert gases was prepared by scientist Neil Barthlete in 1962. This compound 
is 
(A) ?????????? ?? 
(B) ?????? ?? 
(C) ?????? ?? 
(D) ???????? ?? 
Ans: (A) Fact. 
 
Q4:  Boron forms ????
?? type of halides. The correct increasing order of Lewis-acid strength of these 
halides is 
(A) ????
?? >?????? ?? >??????
?? >????
?? 
(B) ????
?? >??????
?? >?????? ?? >????
?? 
(C) ????
?? >????
?? >?????? ?? >??????
?? 
(D) ????
?? >?????? ?? >????
?? >??????
?? 
Ans: (B) (b) Depends on the sizes of the halogens 
 
 
Q5: The compound (?????? ?? )
?? ?? is 
(A) Pyramidal and more basic than (????
?? )
?? ?? 
(B) Planar and less basic than (????
?? )
?? ?? 
(C) Pyramidal and less basic than (????
?? )
?? ?? 
(D) Planar and more basic than (????
?? )
?? ?? 
Ans: (B) (b) It has a lone pair in 2p orbital which is transferred to the empty d-orbital of Si atom 
resulting ???? -???? bonding. 
 
Q6: In a molecule of phosphorus (?? ) oxide, there are 
(A) ???? -?? ,?????? -?? and ???? =?? bonds. 
(B) ?????? -?? and ???? =?? bonds 
(C) ???? -?? and ???? =?? bonds 
(D) ???? -?? ,?????? -?? and ???? =?? bonds 
Ans: (B) 
 
Q7:  When oxalic acid reacts with conc. ?? ?? ????
?? ?? two gases produced are neutral and acidic in 
nature respectively. Potassium hydroxide absorbs one of the two gases. 
The product formed during this absorption and the gas which absorbed are respectively. 
(A) ?? ?? ????
?? and ????
?? 
(B) ???????? ?? and ????
?? 
(C) ?? ?? ????
?? and ???? 
(D) ???????? ?? and ???? 
Ans: (A) 
H
2
C
2
O
4
+H
2
SO
4
?H
2
O+CO+CO
2
KOH+CO
2
?K
2
CO
3
+H
2
O
 
 
Q8: Which of the following is the correct order of acidic strength? 
(A) ????
?? ?? ?? >????
?? >?? ?? ?? ????
 
(B) ????
?? >?? ?? ?? ?? >????
?? 
(C) ????
?? ?? >?????? >????
?? ?? ?? 
(D) ?? ?? ?? >?????? >?????? 
Ans: (A) Acidic strengths increases as electronegativity of atom increases So, Cl
2
O
7
>SO
2
>P
4
O
10
 
 
Q9:  ???? +?? ?? ??????? ?? ?
?
 ?? Compound (A) is used as a/an 
(A) Fertilizer 
(B) Dehydrating agent 
(C) Oxidizing agent 
(D) Reducing agent 
Ans: (A) CaC
2
+N
2
? CaCN
2
?  
Calcium cyanamide 
+C 
 
Q10:  A gas which exists in three allotropic forms ?? ,?? , and ?? is 
(A) ????
?? 
(B) ????
?? 
(C) ????
?? 
(D) ????
?? 
Ans: (B) Fact. 
 
Q11:  When an inorganic compound reacts with ????
?? in aqueous medium, produces (A). (A) on 
reaction with ????
?? ????
?? , gives compound (B) which with sulphur, gives a substance (?? ) used in 
photography. Compound ?? is 
(A) ????
?? ?? 
(B) ????
?? ?? ?? ?? ?? 
(C) ????
?? ????
?? 
(D) ????
?? ?? ?? ?? ?? 
Ans: (D) Self explanatory 
 
Q12: Borax is actually made of two tetrahedral and two triangular units joined together and should 
be written as: ????
?? [ ?? ?? ?? ?? (???? )
?? ]·?? ?? ?? ?? . Consider the following statements about borax: 
(a) Each boron atom has four B-O bonds 
(b) Each boron atom has three B-O bonds 
(c) Two boron atoms have four B-O bonds while other two have three B-O bonds. 
(d) Each boron atom has one -???? groups 
Select correct statement(s) 
(A) a, b 
(B) b, c 
(C) c, d 
(D) a, c 
Ans: C 
 
Q13:  When a compound ?? reacts with ozone in aqueous medium, a compound ?? is produced. 
Ozone also reacts with ?? and produces compound ?? . ?? acts as an oxidizing agent, then ?? ,?? and ?? 
will be 
(A) ?? =???? ,?? =?? ?? and ?? =?????? ?? 
(B) ?? =???? ,?? =?? ?? and ?? =?????? ?? 
(C) ?? =???? ,?? =?? ?? and ?? =?????? ?? 
(D) ?? =???? ,?? =?? ?? and ?? =?????? ?? 
Ans: (A) KI+O
3
+H
2
O?I
2
+KOH+O
2
 
 
Q14:  Aluminium chloride exists as dimer, ????
?? ????
?? in solid state as well as in solution of non -polar 
solvents such as benzene. When dissolved in water, it gives 
(A) [???? (???? )
?? ]
?? -
+???????? 
(B) [???? (?? ?? ?? )
?? ]
?? +
+?????? 
(C) ????
?? +
+?????? 
(D) ????
?? ?? ?? +???????? 
Ans: (D) Al
2
Cl
6
+12H
2
O=2[Al(H
2
O)
6
]
3+
+6Cl
-
 
 
 
Q15:  In the extraction of aluminium the electrolyte is. 
(A) Fused cryolite with feldspar 
(B) Fused cryolite with fluorspar 
(C) Pure alumina in molten cryolite 
(D) Pure alumina with bauxite and molten cryolite 
Ans: (C) Fact. 
 
 
Page 5


JEE Solved Example on P block Element 
JEE Mains 
Q1: ?? ?? ????
?? ?
?
(?? )+????
?? ; is 
(A) Dehydration reaction 
(B) Oxidation reaction 
(C) Disproportionation reaction 
(D) Dephosphorylation reaction 
Ans: (C) H
3
PO
2
?
?
(X)+PH
3
; 
Disproportionation reaction 
 
Q2: Which of the following species is not a pseudohalide? 
(A) ?????? -
 
(B) ???????? -
 
(C) ?????? -
 
(D) ?? ?? -
 
Ans: (B) (b) Pseudohalogen molecules: (meaning"fake" halogens) are inorganic molecules of the 
general forms Ps-Ps or Ps-X, where Ps is a pseudohalogen group such as cyanide, cyanate, 
thiocyanate and others, and ?? is a "true" halogen. 
 
Q3:  First compound of inert gases was prepared by scientist Neil Barthlete in 1962. This compound 
is 
(A) ?????????? ?? 
(B) ?????? ?? 
(C) ?????? ?? 
(D) ???????? ?? 
Ans: (A) Fact. 
 
Q4:  Boron forms ????
?? type of halides. The correct increasing order of Lewis-acid strength of these 
halides is 
(A) ????
?? >?????? ?? >??????
?? >????
?? 
(B) ????
?? >??????
?? >?????? ?? >????
?? 
(C) ????
?? >????
?? >?????? ?? >??????
?? 
(D) ????
?? >?????? ?? >????
?? >??????
?? 
Ans: (B) (b) Depends on the sizes of the halogens 
 
 
Q5: The compound (?????? ?? )
?? ?? is 
(A) Pyramidal and more basic than (????
?? )
?? ?? 
(B) Planar and less basic than (????
?? )
?? ?? 
(C) Pyramidal and less basic than (????
?? )
?? ?? 
(D) Planar and more basic than (????
?? )
?? ?? 
Ans: (B) (b) It has a lone pair in 2p orbital which is transferred to the empty d-orbital of Si atom 
resulting ???? -???? bonding. 
 
Q6: In a molecule of phosphorus (?? ) oxide, there are 
(A) ???? -?? ,?????? -?? and ???? =?? bonds. 
(B) ?????? -?? and ???? =?? bonds 
(C) ???? -?? and ???? =?? bonds 
(D) ???? -?? ,?????? -?? and ???? =?? bonds 
Ans: (B) 
 
Q7:  When oxalic acid reacts with conc. ?? ?? ????
?? ?? two gases produced are neutral and acidic in 
nature respectively. Potassium hydroxide absorbs one of the two gases. 
The product formed during this absorption and the gas which absorbed are respectively. 
(A) ?? ?? ????
?? and ????
?? 
(B) ???????? ?? and ????
?? 
(C) ?? ?? ????
?? and ???? 
(D) ???????? ?? and ???? 
Ans: (A) 
H
2
C
2
O
4
+H
2
SO
4
?H
2
O+CO+CO
2
KOH+CO
2
?K
2
CO
3
+H
2
O
 
 
Q8: Which of the following is the correct order of acidic strength? 
(A) ????
?? ?? ?? >????
?? >?? ?? ?? ????
 
(B) ????
?? >?? ?? ?? ?? >????
?? 
(C) ????
?? ?? >?????? >????
?? ?? ?? 
(D) ?? ?? ?? >?????? >?????? 
Ans: (A) Acidic strengths increases as electronegativity of atom increases So, Cl
2
O
7
>SO
2
>P
4
O
10
 
 
Q9:  ???? +?? ?? ??????? ?? ?
?
 ?? Compound (A) is used as a/an 
(A) Fertilizer 
(B) Dehydrating agent 
(C) Oxidizing agent 
(D) Reducing agent 
Ans: (A) CaC
2
+N
2
? CaCN
2
?  
Calcium cyanamide 
+C 
 
Q10:  A gas which exists in three allotropic forms ?? ,?? , and ?? is 
(A) ????
?? 
(B) ????
?? 
(C) ????
?? 
(D) ????
?? 
Ans: (B) Fact. 
 
Q11:  When an inorganic compound reacts with ????
?? in aqueous medium, produces (A). (A) on 
reaction with ????
?? ????
?? , gives compound (B) which with sulphur, gives a substance (?? ) used in 
photography. Compound ?? is 
(A) ????
?? ?? 
(B) ????
?? ?? ?? ?? ?? 
(C) ????
?? ????
?? 
(D) ????
?? ?? ?? ?? ?? 
Ans: (D) Self explanatory 
 
Q12: Borax is actually made of two tetrahedral and two triangular units joined together and should 
be written as: ????
?? [ ?? ?? ?? ?? (???? )
?? ]·?? ?? ?? ?? . Consider the following statements about borax: 
(a) Each boron atom has four B-O bonds 
(b) Each boron atom has three B-O bonds 
(c) Two boron atoms have four B-O bonds while other two have three B-O bonds. 
(d) Each boron atom has one -???? groups 
Select correct statement(s) 
(A) a, b 
(B) b, c 
(C) c, d 
(D) a, c 
Ans: C 
 
Q13:  When a compound ?? reacts with ozone in aqueous medium, a compound ?? is produced. 
Ozone also reacts with ?? and produces compound ?? . ?? acts as an oxidizing agent, then ?? ,?? and ?? 
will be 
(A) ?? =???? ,?? =?? ?? and ?? =?????? ?? 
(B) ?? =???? ,?? =?? ?? and ?? =?????? ?? 
(C) ?? =???? ,?? =?? ?? and ?? =?????? ?? 
(D) ?? =???? ,?? =?? ?? and ?? =?????? ?? 
Ans: (A) KI+O
3
+H
2
O?I
2
+KOH+O
2
 
 
Q14:  Aluminium chloride exists as dimer, ????
?? ????
?? in solid state as well as in solution of non -polar 
solvents such as benzene. When dissolved in water, it gives 
(A) [???? (???? )
?? ]
?? -
+???????? 
(B) [???? (?? ?? ?? )
?? ]
?? +
+?????? 
(C) ????
?? +
+?????? 
(D) ????
?? ?? ?? +???????? 
Ans: (D) Al
2
Cl
6
+12H
2
O=2[Al(H
2
O)
6
]
3+
+6Cl
-
 
 
 
Q15:  In the extraction of aluminium the electrolyte is. 
(A) Fused cryolite with feldspar 
(B) Fused cryolite with fluorspar 
(C) Pure alumina in molten cryolite 
(D) Pure alumina with bauxite and molten cryolite 
Ans: (C) Fact. 
 
 
Q16:  Boron cannot form which one of the following anions. 
(A) ????
?? ?? -
 
(B) ????
?? -
 
(C) ?? (???? )
?? -
 
(D) ????
?? -
 
Ans: (A) Boron does not have d orbitals in its valence shell and so, maximum covalency of Boron 
cannot exceed 4. So, its cannot form BF
6
-3
. 
 
Q17:  Heating an aqueous solution of aluminium chloride to dryness will give 
(A) ???????? ?? 
(B) ????
?? ????
?? 
(C) ????
?? ?? ?? 
(D) ???? (???? )????
?? 
Ans : (C) Al
2
Cl
6
6H
2
O?Al
2
O
3
+6HCl+3H
2
O 
 
Q18:  The structure of diborane ( ?? ?? ?? ?? ) contains. (2009) 
(A) Four ???? -???? bonds and two ???? -???? bonds 
(B) Two ???? -???? bonds and four ???? -???? bonds 
(C) Two ???? -???? bonds and two ???? -???? bonds 
(D) Four ?? ?? -?? ?? bonds and four ?? ?? -?? ?? bonds 
Ans: (A) 
 
 
Q19:  The stability of dihalides of ???? ,???? ,???? and ???? increases steadily in sequence 
(A) ?????? ?? «?????? ?? «?????? ?? «??????
?? 
(B) ?????? ?? «?????? ?? «??????
?? «?????? ?? 
(C) ?????? ?? «?????? ?? «?????? ?? «??????
?? 
(D) ??????
?? «?????? ?? «?????? ?? «?????? ?? 
Ans: (C) Stability of dihalides increases down the group.