CBSE 11TH CHEMISTRY - Online Test
Q1. Monovalent sodium and potassium ions found in large proportions in biological fluids. They help in
Answer : Option A
Explaination / Solution:
Na and K ions help in transmission of nerve impulses , in regulating the flow of water accross the cell membranes and in the transport of sugar and amino acids in to cells. so monovalent sodium and potassium ions found in large proportions in biological fluids
Q2. Delocalisation of σ-electrons of C -H bond of an alkyl group directly attached to an atom of unsaturated system or to an atom with an unshared p-orbital is called :
Answer : Option D
Explaination / Solution:
The interaction of the electrons in a sigma bond (usually C–H or C–C) with an adjacent empty (or partially filled) non-bonding p-orbital, antibonding σ or π orbital,or filled π orbital, to give an extended molecular orbital that increases the stability of the system is Hyperconjugation.
Q3. Precision and Accuracy refer to _______ of various measurements for the same quantity repeatedly and agreement of a particular value to the ------- -------- of the result , respectively.
Answer : Option A
Explaination / Solution:
Precision means closeness of all the data values measured while accuracy means closeness of particular value with the real value.
For example ,
when the reported values are 2.01, and 1.99 g as the result and its truevalue is 2.00 g .
These values are both precise and accurate.
Q4. At constant temperature, the pressure of a fixed amount (i.e., number of moles n) of gas is?
Answer : Option A
Explaination / Solution:
From ideal gas equation PV=nRT,
keeping n and T fixed,
P α 1/V. (Boyles Law)
Here, T = Temperature
P = Pressure
α. = sign of Proportionality
V = Volume
n= number of moles of gas
R= Universal gas constant
Q5. When the soda bottle is opened, some of the dissolved carbon dioxide gas escapes because of
Answer : Option D
Explaination / Solution:
Soda water, like other carbonated beverages, contains carbon dioxide that has dissolved under pressure. When the pressure is released by opening the soda container, the liquid cannot hold as much carbon dioxide, so the excess bubbles out of the solution. If the soda is left open, additional carbon dioxide will slowly escape into the air. Under warm conditions, the carbon dioxide leaves the solution faster.
Q6. Halogenation of alkanes is a
Answer : Option A
Explaination / Solution:
Halogenation of alkanes is a substitution reaction because the hydrogen atoms are replaced by halogens in the presence of sunlight to give the corresponding alkyl halides.The reaction follows free radical mechanism.
Q7. 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
Q8. 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.
Q9. 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.
Q10. 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.
