CBSE 11TH CHEMISTRY - Online Test
Q1. 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.
Q2. Dihydrogen reacts with dioxygen to form water. The reaction is.
Answer : Option D
Explaination / Solution:
The formation of water from it's elements produces, in addition to water, a tremendous amount of energy, 572 kJ to be exact.
2H2 + O2 2H2O + ENERGY
This is an example of an exothermic reaction, a reaction that produces energy. It is also an example of what is called a combustion reaction, where a substance (in this case hydrogen gas) is combined with oxygen
Q3. bond lengths are lower in elements having
Answer : Option A
Explaination / Solution:
The bond length depends on the strength of the bond. The stronger the bond is, the shorter it will be. The triple bonds are the strongest and hence the shortest. Then comes double bonds which are of intermediate strength between the triple and single bonds. And finally the single bonds are weaker than the other two. This way, Triple bonds are the shortest. Then comes double bonds. Finally, single bonds are the longest among the three.
The order of bond lengths is given as, Triple bond < Double bond < Single bond
Q4. Divalent magnesium and calcium ions are found in large proportions in biological fluids.
Answer : Option B
Explaination / Solution:
and maintains the ion balance.
Q5. Hyperconjugation in an organic compound is a
Answer : Option A
Explaination / Solution:
Hyperconjugation in an organic compound is a stabilizing interaction
Q6.
Answer : Option D
Explaination / Solution:
Scientific notation is conveniently used to represent extremely large or even very small numerical values . It is an exponential notation in which any number can be represented in the form , N x 10n , where n is an exponent having positive or negative values and N can vary between 1 and 10 , but not 10 itself.
Q7. Charles’ law states that pressure remaining constant, the volume of a fixed mass of a gas is
Answer : Option B
Explaination / Solution:
P α T (at constant V).
Q8. The dynamic nature of chemical equilibrium can be demonstrated in the synthesis of ammonia by Haber.s process. Choose the appropriate option given below
Answer : Option A
Explaination / Solution:
Use of isotope (deuterium) in the formation of ammonia clearly indicates that chemical reactions reach a state of dynamic equilibrium in which the rates of forward and reverse reactions are equal and there is no net change in composition.
Q9. General formula for alkenes is
Answer : Option C
Explaination / Solution:
Alkenes are unsaturated hydrocarbons with atleast on double bond between the carbon atoms.Their general formula is CnH2n.
Q10. The highest value of oxidation number changes from 1 to 7
Answer : Option D
Explaination / Solution:
The highest value of oxidation number exhibited by an atom of an element generally increases across the period in the periodic table.
