CBSE 11TH CHEMISTRY - Online Test
Q1. The alkali metals burn vigorously in oxygen forming oxides. Hence, potassium forms
Answer : Option A
Explaination / Solution:
alkali metals burns vigorously to form superoxides. Superoxide O2- ion is only in the presence of large cations such as potassium, Rb and Cs
Q2. Which is the correct form of van der Waals equation?
Answer : Option A
Explaination / Solution:
is vanderwall gas equation of real gases.
Q3. If the Kc is neither too small nor too large, one of the following will happen
Answer : Option C
Explaination / Solution:
Rxn is at equilibrium.
Q4. Thus ethyne molecule consists of
Answer : Option C
Explaination / Solution:
Ethyne is an unsaturated compound which belongs to the alkyne family and has the formula C2H2.Thus it consists of one C–C σ bond, two C–H σ bonds and two C–C π bonds.
Q5. One of the following has application in electrode processes and cells
Answer : Option B
Explaination / Solution:
The concept of redox reaction is used in electrode processes and cells. Because in these processes an electrode loose or gain electrons, electrode with higher reduction potential undergo reduction, electrode potential is given a positive sign if oxidation occures at the electrode.
Q6. Enthalpy of solution of a substance is the enthalpy change
Answer : Option D
Explaination / Solution:
Enthalpy of solution of a substance is the enthalpy change when one mole of it dissolves in a specified amount of solvent
Q7. All the orbitals in the valence shell of the noble gases
Answer : Option A
Explaination / Solution:
These elements are called noble elements beacuse they contain ns2, np6 valence shell electronic configuration. A complete octet in the outermost shell makes these elements chemically stable, and therefore they do not easily react with other elements to form compounds.
Q8. According to quantum theoretical model of an atom each orbital is designated by three quantum numbers labelled as n, l and ml. The values these can take are
Answer : Option D
Explaination / Solution:
n (Principal quantum number) value tell about the shell to which the electro belong, Ex,If n=1 electron belongs to first shell (K) around the nucleus
l (Azimuthal quantum number) tell about angular momentum, and shape of the orbitals, and it designates the subshells to which the electron belongs to. For a given value of 'n', ' l' can have value ranging from 0 to n-1. Ex, If n=2 then , the value of 'l' will be 0 and 1 (0 to n-1)
ml ( Magnetic orbital quantum number) determines the number of preferred orientations of the orbitals in the subshell, which are defined by given 'l' value. ex if 'l'= 2 then ml = 2l+1 =2*2 +1= 5 m value ie., m = +2,+1,0,-2,-1
Q9. Which of the following pollutant gases naturally occurs in the environment :
Answer : Option D
Explaination / Solution:
SO2 is a naturally occurring pollutant gas with an approximate atmospheric concentration of 1 ppm. It is produced naturally by volcanic activities and burning of fossil fuels contaning sulphur.
Q10. According to the law of conservation of mass, a balanced chemical equation
Answer : Option C
Explaination / Solution:
According to law of conservation of mass
total mass of reactants
= total mass of product
∴ the number . of atoms of each element in reactants
= number . of atoms of that element in products
