Chemistry - Online Test
Q1. Oxidation number denotes the oxidation state of an element in a compound ascertained on the basis that electron in a covalent bond belongs
Answer : Option C
Explaination / Solution:
Oxidation number is a number assigned to an element in a compound according to some rules. This number enable us to describe oxidation-reduction reactions, and balancing redox chemical reactions. When a covalent bond forms between two atoms with different electronegativities the shared electrons in the bond lie closer to the more electronegative atom eg. HCl
The oxidation number of an atom is the charge that results when the electrons in a covalent bond are assigned to the more electronegative atom. It is the charge on an atom would possess if the bonding were ionic. In HCl (above) the oxidation number for the hydrogen would be +1 and that of the Cl would be -1
Q2. The number of atoms per unit cell in a body centered cubic structure is
Answer : Option C
Explaination / Solution:
Atoms at corner contribute 1 to a unit cell and one atom is present in body center contribute 1. So total no. of atoms per unit cell is 2.
Q3.
is a polymer obtained from?
Answer : Option A
Explaination / Solution:
This is polymer obtained from monomer styrene
Q4. Which compound is used as the cooling liquid in refrigerators?
Answer : Option C
Explaination / Solution:
NH3 is used as cooling liquid in refrigerators
Q5. The relationship between and CV for an ideal gas is
Answer : Option D
Explaination / Solution:
For ideal gas Cp- CV = nR. For1 mole of gas n=1.
Q6. The process of separating gangue and other impurities from the metals is known as
Answer : Option D
Explaination / Solution:
Process of removal of impurities from ore is known as concentration of ore or benefication of ore.
Q7. Choose one of the following in the order of increasing radii:
Answer : Option C
Explaination / Solution:
Size of anion is greater than the size of parent atom and size of cation. As the –ve charge of anion increases ionic radii increases due to decrease in the effective nuclear charge and vice versa.
Q8. Photoelectric effect established that light
Answer : Option D
Explaination / Solution:
The emission of free electrons from a metal surface when light is shone on it is called the photoemission or the photoelectric effect. This effect led to the conclusion that light is made up of packets or quantum of energy. Einstein already associated the light quantum with momentum. This strongly supported the particle nature of light and these particles were named photons. Thus, the wave-particle duality of light came into picture. Einstein won the Nobel Prize for Physics not for his work on relativity, but for explaining the photoelectric effect.
Q9. Sewage containing organic waste should not be disposed in water bodies because it causes major water pollution. Fishes in such a polluted water bodies die because of :
Answer : Option C
Explaination / Solution:
Organic waste disposed in water bodies causes the death of fishes because bacteria present in them decompose the organic waste and consume oxygen in it leaving lesser oxygen for fishes and other aquatic animals for respiration.
Q10. Electronic configuration of Cu3+ is
Answer : Option B
Explaination / Solution:
Cu has atomic number 29.
