CBSE 11TH CHEMISTRY - Online Test
Q1. A known mass of an organic compound is heated with fuming nitric acid in the presence of silver nitrate is:
Answer : Option B
Explaination / Solution:
This is known as carius method.
Q2. When sodium is dissolved in liquid ammonia, a solution of deep blue colour is obtained. The colour of the solution is due to
Answer : Option B
Explaination / Solution:
The color of solution is due to the presence of ammoniated electron.
Q3. Above the Critical temperature of carbon dioxide
Answer : Option D
Explaination / Solution:
Tc is the highest Temp where a gas can exist in liquid state. Above this no liquid state exist hence it is not possible to liquify the gas no matter what pressure is applied.
Q4. A catalyst increases the rate of the chemical reaction for the conversion of reactants to products by
Answer : Option C
Explaination / Solution:
A catalyst increases the rate of the chemical reaction by making available a new low energy pathway for the conversion of reactants to products. It increases the rate of forward and reverse reactions that pass through the same transition state and does not affect equilibrium. Catalyst lowers the activation energy for the forward and reverse reactions by exactly the same amount. Catalyst does not affect the equilibrium composition of a reaction mixture. It does not appear in the balanced chemical equation or in the equilibrium constant expression.
Q5. The unusual behavior of benzene is explained by
Answer : Option D
Explaination / Solution:
resonance stabilisation explains the unusual stability of benzene.There is pi electron delocalisation in the ring which enhances the stability of the molecule.
Q6. In oxygen difluoride and dioxygen difluoride, the oxygen is assigned an oxidation number of
Answer : Option A
Explaination / Solution:
Oxidation state of O in OF2 is +2 and O2F2 is +1. Because the number assigned to oxygen will depend upon the bonding state of oxygen.
Q7. We can calculate the change in entropy of a reversible process by
Answer : Option B
Explaination / Solution:
is used to measure entropy system undergoin reversible
Q8. Which of the following statements is false?
Answer : Option B
Explaination / Solution:
The elements of Group 1 (alkali metals) have ns1 as outermost electronic configuration. They are all reactive metals with low ionization enthalpies. They lose the outermost electron readily to form 1+ ion. The compounds of the alkali, with the exception of those of lithium are predominantly ionic.
Q9. The Aufbau principle states : In the ground state of the atoms, the orbitals are filled in order of
Answer : Option D
Explaination / Solution:
The Aufbau Principle states that in the ground state of an atom, an electron enters the orbital with lowest energy first and subsequent electrons are fed in the order of increasing energies. The word 'aufbau' in German means 'building up'. Here, it refers to the filling up of orbitals with electrons.
Q10. Measure of the amount of organic material in the water, in terms of how much oxygen will be required to break it down biologically is termed as :
Answer : Option C
Explaination / Solution:
Measure of the amount of organic material in the water, in terms of how much oxygen will be required to break it down biologically is termed as Biochemical Oxygen Demand (BOD)
