CHEMISTRY THE P-BLOCK ELEMENTS-11th
QUIZ-20
Dear Readers,
IIT JEE exam which consists of JEE Main and JEE Advanced is one of the most important entrance exams for engineering aspirants. The exam is held for candidates who are aspiring to pursue a career in the field of engineering and technical studies.
Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything..
Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything..
Q1.Name of structure of silicates in which three oxygen atoms of [SiO4]4-are shared is
Solution
The structure of silicates has been found with the help of X-ray diffraction technique. All silicates have tetrahedral SiO44- ion as a basic building unit i.e., all silicates are composed of many units. Tetrahedral shape of [SiO4]4- ion is due to sp3-hybridisation of Si-atom. Sheet silicates are formed when three oxygen atoms (bridging O-atoms) of each (SiO4)4- unit are shared. Hence, the general formula of sheet silicates is (Si2O5)2n-
The structure of silicates has been found with the help of X-ray diffraction technique. All silicates have tetrahedral SiO44- ion as a basic building unit i.e., all silicates are composed of many units. Tetrahedral shape of [SiO4]4- ion is due to sp3-hybridisation of Si-atom. Sheet silicates are formed when three oxygen atoms (bridging O-atoms) of each (SiO4)4- unit are shared. Hence, the general formula of sheet silicates is (Si2O5)2n-
Q2.Among the following, the paramagnetic compound is
Solution
KO2 ⇌ K+ + O2-
O2- (superoxide) is paramagnetic
KO2 ⇌ K+ + O2-
O2- (superoxide) is paramagnetic
Q3.Nylon-6 is formed from caprolactam which is formed from
Solution
Cyclohexanone and hydroxyl amino
When cyclohexanone is reacted with hydroxyl amino in presence of acidic medium then caprolactam is formed, which is used for nylon-6 production.
Cyclohexanone and hydroxyl amino
When cyclohexanone is reacted with hydroxyl amino in presence of acidic medium then caprolactam is formed, which is used for nylon-6 production.
Q4.Select ionic carbides
Solution
Al4C3, CaC2, Mg2C3
Carbide is a compound of carbon with less electronegative element. The most electropositive metals form ionic carbides. Examples: Al4C3, CaC2, Mg2C3 Non-metals of electronegativity similar to that of carbon form covalent carbides.
Example: SiC,B4C
Al4C3, CaC2, Mg2C3
Carbide is a compound of carbon with less electronegative element. The most electropositive metals form ionic carbides. Examples: Al4C3, CaC2, Mg2C3 Non-metals of electronegativity similar to that of carbon form covalent carbides.
Example: SiC,B4C
Q5.SiCl4 is hydrolysed but CCl4 is not hydrolysed because
Solution
Si has vacant d-orbital and can accommodate lone-pair of electrons from oxygen of water
SiCl4 is hydrolysed but CCl4 is not hydrolyzed because Si has vacant d-orbitals and can accommodate a lone pair of electrons from the oxygen of water whereas C does not have vacant d-orbitals to accommodate a lone pair of electrons.
Si has vacant d-orbital and can accommodate lone-pair of electrons from oxygen of water
SiCl4 is hydrolysed but CCl4 is not hydrolyzed because Si has vacant d-orbitals and can accommodate a lone pair of electrons from the oxygen of water whereas C does not have vacant d-orbitals to accommodate a lone pair of electrons.
Q6.Carbon suboxide (C3O2) is formed when
Solution
Malonic acid reacts with P4O10
Malonic acid reacts with P4O10
Q7.Which fumes in moist air?
Solution
AlCl3 fumes in moist air
White fumes are due to the presence of HCl gas. Anhydrous aluminium chloride is hydrolysed partially with the moisture in the atmosphere to give HCl gas. This HCl combines with the moisture in the air and appears white in colour.
AlCl3 + 3H2O ⟶ Al(OH)3 + 3HCl(white fumes)
AlCl3 fumes in moist air
White fumes are due to the presence of HCl gas. Anhydrous aluminium chloride is hydrolysed partially with the moisture in the atmosphere to give HCl gas. This HCl combines with the moisture in the air and appears white in colour.
AlCl3 + 3H2O ⟶ Al(OH)3 + 3HCl(white fumes)
Q8.Consider the following statements
I: Boric acid is a mild antiseptic and is used as a food preservative
II: Borax and other borates are used in water-treatment, timber preservation, glass manufacture
III: Sodium peroxoborate is an important constituent of washing powder
Solution
I, II, III
I, II, III
Q9.Which of the following statements is/are correct?
Solution
Boric acid is Lewis acid, Boron possess sp2 hybridisaion and their molecules are held together by hydrogen bonding
Boric acid is Lewis acid, Boron possess sp2 hybridisaion and their molecules are held together by hydrogen bonding
Q10. Which of the following reaction is incorrect?
Solution
Only one electron pair of pyridine can be accommodated not two electron pairs
Only one electron pair of pyridine can be accommodated not two electron pairs
