CBSE 11TH CHEMISTRY - Online Test
Q1. Which of the following method is not a synthetic method for production of Benzene?
Answer : Option A
Explaination / Solution:
Since isolation of benzene from coal tar involves separation of benzene from other components through a physical operation "fractional distillation" , it is NOT a synthetic method for production of benzene.
Q2. Assign oxidation number to P in
Answer : Option D
Explaination / Solution:
Oxidation state of P in NaH2PO4 is +5.
Let the oxidation number of P be x. As we already know oxidation number of other atoms so we can calculate that of P too.
Na = +1
H= +1 (+2 for hydrogen molecule)
O = -2
Now calculating oxidation number of P:-
1 +2 + x +(-8) = 0
On solving we get x= +5.
Q3.
Consider the chemical equation ,
----- KOH + ----- H3PO4 → ----- K3PO4 + ----- H2O.
The equation can be balanced by inserting the following in blank spaces
Answer : Option C
Explaination / Solution:
The given equation gets balanced by inserting the coefficients (3 , 1 ,1 ,3 ) in blank spaces from LHS to RHS . Thus, the balanced equation for the given reacion is ,
3KOH + H3PO4 → K3PO4 + 3H2O.
Q4. In Friedel-Crafts alkylation reaction, when benzene is treated with an alkyl halide in the presence of a catalyst, alkylbenene is formed. The catalyst used is
Answer : Option A
Explaination / Solution:
the acid chloride or anhydride reacts with anhydrous aluminium chloride to form the acylium ion which serves as an electrophile which then attacks the benzene ring to give alkylbenzene.
Q5. Standard Gibbs energy change is related to the equilibrium constant of the reaction as follows:
Answer : Option D
Explaination / Solution:
= -RTln K
where is standard Gibbs energy change, K is equilibrium constant, R is universal gas constant and T is temperature in kelvin scale
Q6. In the periodic table Electronegativity generally
Answer : Option D
Explaination / Solution:
The electronegativity value increases as the effective nuclear charge on the atomic nucleus increases. In a period moving from left to right, the electronegativity increases due to decrease in atomic radii resulting an increase in effective nuclear charge. Whereas, in a group moving from top to bottom, the electronegativity decreases because atomic radius increases due to subsequent addiiton of shells.
Q7. Daltons atomic theory could not explain one of the following
Answer : Option C
Explaination / Solution:
Daltons theory said atom is indivisible in nature so it doesnot explain the existence of subatomic particles.
The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. However an atom is the smallest particle that takes part in chemical reactions.
Q8. Reducing potentially hazardous waste through smarter productions is called :
Answer : Option D
Explaination / Solution:
Metathesis is the method developed by noble prize winning trio, Chauvin, Grubbs and Schrock. It is a method in organic synthesis in which a certain group of atoms are rearranged in a molecule so that a molecule with lesser harmful effect is produced.
Q9. How many hydrogen-bonded water molecule(s) are associated in
Answer : Option A
Explaination / Solution:
In crystal structure of Copper sulphate pentahydrate there only 4 water molecule of hydration and one water molecule is associated with hydrogen bonding interaction.
Q10. The shape of the below molecule is
Answer : Option C
Explaination / Solution:
Bent shape is the shape of a molecule with 3 atoms that have a bond angle less than 180°.
