9th Standard Syllabus & Materials
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Published on: 16/06/2021
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Questions + Answers key
Take MCQ Science Test1.
Discuss in brief about the properties of Coordinate covalent compounds.
2.
Identify the incorrect statement and correct them.
a. Like covalent compounds, Coordinate compounds also contain charged particles (ions), so they are good conductors of electricity.
b. Ionic bond is a weak bond when compared to Hydrogen bond.
c. Ionic or electrovalent bonds are formed by mutual sharing of electrons between atoms.
d. Loss of electrons is called Oxidation and Gain of electron is called Reduction.
e.The electrons which are not involved in bonding are called valence electrons.
3.
Give an example for each of the following statements.
a. A compound in which two Covalent bonds are formed
b. A compound in which one ionic bond is formed
c. A compound in which two Covalent and one Coordinate bonds are formed
d. A compound in which three covalent bonds are formed
e. A compound in which Coordinate bond is formed
4.
List down the differences between Ionic and Covalent compounds.
5.
Find the oxidation number of the elements in the following compounds.
a. C in CO2
b. Mn in MnSO4
c. N in HNO3
1.
The compounds containing coordinate covalent bonds are called coordinate compounds.
(a) Physical state - These compounds exist as gases, liquids or solids.
(b) Electrical conductivity - Like covalent compounds, co-ordinate compounds also do not contain charged particles (ions), so they are bad conductors of electricity.
(c) Melting point - These compounds have melting and boiling points higher than those of purely covalent compounds but lower than those of purely ionic compounds.
(d) Solubility - Insoluble in polar solvents like water but are soluble in non-polar solvents like benzene, CCI4, and toluene.
(e) Reactions - Coordinate covalent compounds undergo molecular reactions which are slow.
2.
(a) Like covalent compounds, coordinate compounds also do not contain charged particles (ions) so they are bad conductors of electricity.
(b) Ionic bond is a strong bond when compared to Hydrogen bond.
(c) Ionic or electrovalent bonds are formed by transfer of electrons between atom.
(e) The electron which are involved in bonding are called valence electrons.
3.
a) Formation of Oxygen molecule (O2)
b) Formation of Sodium chloride (NaCl)
c) Formation of Ammonia and BF3 molecules
d) Formation of Nitrogen molecule (N2)
e) Formation of Ammonium Ion.
4.
| S.No | Ionic Compounds | Covalent Compounds |
| 1. | Formed by the transfer of electrons from a metal to a non-metal atom. | Formed by sharing of electrons between non-metal atoms. |
| 2. | Strong electrostatic force of attraction between cations and anions | Mutual sharing of electrons and so weak force of attraction between atoms. |
| 3. | Solids at room temperature. | Gases, liquids and soft solids |
| 4. | Conducts electricity in molten state or in solutions | Non-conductors of electricity |
| 5. | Have high melting and boiling points | Have low melting and boiling points. |
| 6. | Soluble in polar solvents. | Soluble in non-polar solvents |
| 7. | Hard and brittle | Soft and waxy. |
| 8. | Undergo ionic reaction which are fast and instantaneous. | Undergo molecular reactions which are slow. |
5.
a) C in CO2
Let C be x and we know O = -2
So,
(x) + 2 x (-2) = 0
x + (-4) = 0
x = +4
So oxidation number of carbon is +4.
b) Mn in MnSO4
Let on Mn be x and we know S is +6, O is -2
So,
(x) + (1 x +6) + (4 x -2) = 0
x + 6 + (-8) = 0
x - 2 = 0
x = +2
Oxidation number of Mn is +2.
c) N in HNO3
Let N be x and we know H is +1 and 0 is -2
So,
(+1) + (x) + 3 x (-2) = 0
+1 + (x) - 6 = 0
x - 5 = 0
x = +5
Oxidation number of N is +5.
9th Standard Syllabus & Materials
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Tamilnadu Stateboard 9th Standard Subjects
Tamilnadu Stateboard Standards
