12th Grade > Chemistry
P BLOCK ELEMENTS MCQs
Total Questions : 30
| Page 1 of 3 pages
Question 1. A white coloured inorganic salt gives the following reactions.
(i) It is soluble in water and the solution has sweet taste.
The solution turns black in presence of H2S
ii) The solution gives a white precipitate with dilute HCl which is soluble in hot water.
iii) The salt when heated gives acetone and a yellow coloured residue. Identify the salt (A) and give chemical reactions.
(i) It is soluble in water and the solution has sweet taste.
The solution turns black in presence of H2S
ii) The solution gives a white precipitate with dilute HCl which is soluble in hot water.
iii) The salt when heated gives acetone and a yellow coloured residue. Identify the salt (A) and give chemical reactions.
Answer: Option C. -> Pb(CH3COO)2
:
C
(A)isPb(CH3COO)2Pb(CH3COO)2+H2S→PbS+2CH3COOHBlackPb(CH3COO)2+2HCl→PbCl2+2CH3COOHSoluble in hot waterPb(CH3COO)2→PbO+CO2+CH3COCH3]
:
C
(A)isPb(CH3COO)2Pb(CH3COO)2+H2S→PbS+2CH3COOHBlackPb(CH3COO)2+2HCl→PbCl2+2CH3COOHSoluble in hot waterPb(CH3COO)2→PbO+CO2+CH3COCH3]
Answer: Option D. -> Fluorspar
:
D
Fluorspar ; CaF2
:
D
Fluorspar ; CaF2
Answer: Option A. -> Lower the melting point of alumina
:
A
Melting point of AI2O3is very high, adding impurities reduces melting point
:
A
Melting point of AI2O3is very high, adding impurities reduces melting point
Answer: Option A. -> C-O bond energy is low
:
A
C - O bond energy is 358 kj .mol−1
Si - O bond energy is368 kj . mol−1
:
A
C - O bond energy is 358 kj .mol−1
Si - O bond energy is368 kj . mol−1
Question 5. An inorganic compound (A) is a strong reducing agent. Its hydrolysis in water gives a white turbidity (B). Aqueous solution of (A) gives a white precipitate (C) with NaOH solution which is soluble in excess of NaOH. (A) reduces auric chloride to produce purple of cassius. (A) also reduces iodine and gives chromyl chloride test. What is 'B' in the chemical reactions.
Answer: Option B. -> Sn(OH)Cl
:
B
(A)=SnCl2;(B)=Sn(OH)Cl:(C)=Sn(OH)2SnCl2+H2O→Sn(OH)Cl+HCl(A)(B)SnCl2+NaOH→Sn(OH)2+2NaCl,Sn(OH)2+2NaOH→Na2SnO2+2H2O3SnCl2+2AuCl3→3SnCl4+2AuSnCl2+2HCl+l2→SnCl4+2Hl
:
B
(A)=SnCl2;(B)=Sn(OH)Cl:(C)=Sn(OH)2SnCl2+H2O→Sn(OH)Cl+HCl(A)(B)SnCl2+NaOH→Sn(OH)2+2NaCl,Sn(OH)2+2NaOH→Na2SnO2+2H2O3SnCl2+2AuCl3→3SnCl4+2AuSnCl2+2HCl+l2→SnCl4+2Hl
Answer: Option C. -> Sn(OH)Cl
:
C
(CH3)2Si(OH)2formed will lose a water molecule to form long chains.
:
C
(CH3)2Si(OH)2formed will lose a water molecule to form long chains.
Answer: Option D. -> (X)≡CaC2(Y)≡CO(Z)≡CaCN2(P)≡NH3
:
D
X = CaC2, heating calcium carbide with N2 gives calcium cyanamide (CaCN2), which in turn liberates NH3on hydrolysis
:
D
X = CaC2, heating calcium carbide with N2 gives calcium cyanamide (CaCN2), which in turn liberates NH3on hydrolysis
Answer: Option B. -> Of inert pair effect
:
B
Inert pair effect is the phenomenon in which outer shell (ns2)electrons penetrate to
(n - 1) d electrons and thus becomes closer to nucleus and are more effectively pulled towards nucleus. This results in less availability of ns electrons for bonding. The inert pair effects begins when n =4 and increases with increasing value of n.
:
B
Inert pair effect is the phenomenon in which outer shell (ns2)electrons penetrate to
(n - 1) d electrons and thus becomes closer to nucleus and are more effectively pulled towards nucleus. This results in less availability of ns electrons for bonding. The inert pair effects begins when n =4 and increases with increasing value of n.
Answer: Option C. -> Washing soda reacts with aluminium to form soluble aluminate
:
C
2NaOH+2Al+2H2O→2NaAlO2+3H2
:
C
2NaOH+2Al+2H2O→2NaAlO2+3H2
Answer: Option A. -> Acidic
:
A
K2SO4.AI2(SO4)3.24H2OK2SO4+H2O→K(OH)+H2SO4AI2(SO4)3+H2O→Al(OH)3+H2SO4
:
A
K2SO4.AI2(SO4)3.24H2OK2SO4+H2O→K(OH)+H2SO4AI2(SO4)3+H2O→Al(OH)3+H2SO4