CBSE 11th Standard Chemistry Subject HOT Questions 1 Mark Questions 2021
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CBSE 11th Standard Chemistry Subject HOT Questions 1 Mark Questions 2021
11th Standard CBSE
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Reg.No. :
Chemistry
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Neutrons can be found in all atomic nuclei except in one case. Which is this atomic nucleus and what does it consist of ?
(a)In case of hydrogen atom, there is no neutron. It consists of only one proton
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Explain why uncertainty principle is significant only for the motion of sub-atomic particle but is negligible for the macroscopic objects?
(a)The energy of photon is sufficient to disturb a sub-automic particle so that there is uncertainty in the measurement of position and momentum of the sub-atomic particle. However the energy is insufficient to disturb a macroscopic object.
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Why AIF3 is a high melting solid whereas SiF4 is a gas?
(a)AIF3 is an ionic compound whereas SiF4 is a non-polar covalent compound. Hence, interparticle forces in AIF3 are much stronger that's why it is a high melting solid.
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How many nodal planes are present in \(\pi ({ 2p }_{ x })\) and \( \pi{ \times}({ 2p }_{ x })\) molecular orbitals?
(a)One and two respectively.
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What would have happened to the gas if the molecular collision were not elastic?
(a)On every collision, there would have been loss of energy.As a result, the molecules would have slowed down and ultimately settle down in the vessel.Moreover, the pressure would have gradually reduced to zero.
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Water can be lifted into the water tank at the top of the house with the help of a pump. Then why is it not considered to be spontaneous?
(a)A spontaneous process should occur continuously by itself after initiation. But this is not so in the given case because water will go up as long as the pump is working.
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Air contains about 99% of N2 and O2 gases. Why do not they combine to form NO under the standard conditions? Standard Gibbs energy of formation of NO (g) is 86.7 kJ mol-1.
(a)For the combination of N2 and O2 to form NO, the standard Gibbs energy of formation, is +ve
\(\frac { 1 }{ 2 } N_{ 2 }(g)+\frac { 1 }{ 2 } O_{ 2 }(g)\rightarrow NO(g)(\Delta _{ f }{ G }_{ NO }^{ \circ }=+86.7 \ kJmol^{ -1 })\)
Therefore, this reaction is non-spontaneous under the standard conditions and hence N2 and O2 do not combine. -
Why is anode called oxidation electrode, whereas cathode is called reduction electrode?
(a)At the anode, loss of electrodes takes place, ie. oxidation takes place, whereas cathode, a gain of electrodes takes place, ie. reduction takes place.Therefore, the cathode is called reduction electrode and anode is called oxidation electrode.
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Can Fe3+ oxidise Br- to Br2 at 1 M concentrations?
Eo(Fe3+ I Fe2+) = 0.77 V and Eo (Br I Br - ) = 1.09V(a)Eo(Fe3+ I Fe2+)is lower than that of Eo (Br I Br - ).Therefore, Fe2+ can reduce Br2 bur Br - cannot reduce Fe3+. Thus, Fe3+ cannot oxidise Br - to Br2
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Describe the bulk preparation of hydrogen by electrolytic method. What is the role of an electrolyte in this process?
(a)Electrolysis of acidified water using platinum electrodes gives hydrogen.
\(2{ H }_{ 2 }O(l)\overset { Electrolysis }{ \underset { Traces \ of \ acid/base }{ \rightarrow } } 2{ H }_{ 2 }(g)+{ O }_{ 2 }(g)\\ \)
Here, the role of an electrolyte is to make water conducting.
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CBSE 11th Standard Chemistry Subject HOT Questions 1 Mark Questions 2021 Answer Keys
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In case of hydrogen atom, there is no neutron. It consists of only one proton
In case of hydrogen atom, there is no neutron. It consists of only one proton
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The energy of photon is sufficient to disturb a sub-automic particle so that there is uncertainty in the measurement of position and momentum of the sub-atomic particle. However the energy is insufficient to disturb a macroscopic object.
The energy of photon is sufficient to disturb a sub-automic particle so that there is uncertainty in the measurement of position and momentum of the sub-atomic particle. However the energy is insufficient to disturb a macroscopic object.
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AIF3 is an ionic compound whereas SiF4 is a non-polar covalent compound. Hence, interparticle forces in AIF3 are much stronger that's why it is a high melting solid.
AIF3 is an ionic compound whereas SiF4 is a non-polar covalent compound. Hence, interparticle forces in AIF3 are much stronger that's why it is a high melting solid.
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One and two respectively.
One and two respectively.
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On every collision, there would have been loss of energy.As a result, the molecules would have slowed down and ultimately settle down in the vessel.Moreover, the pressure would have gradually reduced to zero.
-
A spontaneous process should occur continuously by itself after initiation. But this is not so in the given case because water will go up as long as the pump is working.
A spontaneous process should occur continuously by itself after initiation. But this is not so in the given case because water will go up as long as the pump is working.
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For the combination of N2 and O2 to form NO, the standard Gibbs energy of formation, is +ve
1/2N2(g)+1/2O2(g)→NO(g)(ΔfG∘NO = +86.7 kJmol−1)
Therefore, this reaction is non-spontaneous under the standard conditions and hence N2 and O2 do not combine.For the combination of N2 and O2 to form NO, the standard Gibbs energy of formation, is +ve
1/2N2(g)+1/2O2(g)→NO(g)(ΔfG∘NO = +86.7 kJmol−1)
Therefore, this reaction is non-spontaneous under the standard conditions and hence N2 and O2 do not combine. -
At the anode, loss of electrodes takes place, ie. oxidation takes place, whereas cathode, a gain of electrodes takes place, ie. reduction takes place.Therefore, the cathode is called reduction electrode and anode is called oxidation electrode.
At the anode, loss of electrodes takes place, ie. oxidation takes place, whereas cathode, a gain of electrodes takes place, ie. reduction takes place.Therefore, the cathode is called reduction electrode and anode is called oxidation electrode.
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Eo(Fe3+ I Fe2+)is lower than that of Eo (Br I Br - ).Therefore, Fe2+ can reduce Br2 bur Br - cannot reduce Fe3+. Thus, Fe3+ cannot oxidise Br - to Br2
Eo(Fe3+ I Fe2+)is lower than that of Eo (Br I Br - ).Therefore, Fe2+ can reduce Br2 bur Br - cannot reduce Fe3+. Thus, Fe3+ cannot oxidise Br - to Br2
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Electrolysis of acidified water using platinum electrodes gives hydrogen. \(2{ H }_{ 2 }O(l)\overset { Electrolysis }{ \underset { Traces \ of \ acid/base }{ \rightarrow } } 2{ H }_{ 2 }(g)+{ O }_{ 2 }(g)\\ \) Here, the role of an electrolyte is to make water conducting.
