Redox Reactions CBSE Questions & Answers

Redox Reactions

This is Chemistry Class 11 Redox Reactions CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
\({\text{2 N}}{{\text{a}}^ + }\left( {\text{s}} \right){\text{ }} \to {\text{ 2 N}}{{\text{a}}^ + }\left( {\text{g}} \right){\text{ }} + {\text{ 2}}{e^ - }\)\(H2(g) + 2{e^ - }{\text{n}}?2H + (g)\)
  • A
    sodium is oxidised and hydrogen is reduced
    Correct
  • B
    sodium is reduced
  • C
    hydrogen is oxidised
  • D
    electronegativity of sodium determines the direction of the reaction
2
In the free or the uncombined state, each atom in \({{\text{O}}_{\text{2}}}{{\text{O}}_{\text{3}}},{\text{ }}{{\text{P}}_{\text{4}}},{\text{ }}{{\text{S}}_{\text{8}}}\) and Mg has the oxidation number
  • A
    seven
  • B
    two
  • C
    zero
    Correct
  • D
    three
3
For ions composed of only one atom, the oxidation number is equal to the
  • A
    charge on the ion
    Correct
  • B
    always -1
  • C
    always +1
  • D
    sum of different oxidation states
4
Hydrogen is prepared from $H_2O$ by adding
  • A
    AI, which acts as oxidising agent
  • B
    Au, which acts as oxidising agent
  • C
    Ca, which acts as reducing agent
    Correct
  • D
    Ag, which acts as reducing agent
5
An oxidation number of +1 is found in all their compounds of one of the below given options
  • A
    all transition elements
  • B
    all alkaline earth metals
  • C
    superoxides
  • D
    all alkali metals
    Correct
6
An oxidation number of +1 is found in all their compounds of one of the below given options
  • A
    all alkaline earth metals
    Correct
  • B
    all transition elements
  • C
    all alkali metals
  • D
    superoxides
7
The oxidation number of hydrogen in LiH, NaH and CaH2 is
  • A
    -1 and -2
  • B
    -2
  • C
    1and 2
  • D
    -1.0
    Correct
8
Chlorine, bromine and iodine when combined with oxygen, have oxidation numbers
  • A
    -1 or any negative number
  • B
    -1
  • C
    +1 or any positive number
    Correct
  • D
    -2
9
The oxidation number of an element in a compound is evaluated on the basis of certain rules. Which of the following rules is not correct in this respect?
  • A
    The oxidation number of hydrogen is always +1.
    Correct
  • B
    The algebraic sum of all the oxidation numbers in a compound is zero.
  • C
    In all its compounds, the oxidation number of fluorine is – 1.
  • D
    An element in the free or the uncombined state bears oxidation number zero.
10
The more positive the value of E0, the greater is the tendency of the species to get reduced. Using the standard electrode potential of redox couples given below find out which of the following is the strongest oxidising agent. \(E0values:Fe3 + /Fe2 + = + 0.77;I2(s)/{l^ - } = + 0.54;\) \({\text{C}}{{\text{u}}^{{\text{2}} + }}/{\text{Cu }} = {\text{ }} + {\text{ }}0.{\text{34}};{\text{ A}}{{\text{g}}^ + }/{\text{Ag }} = {\text{ }} + {\text{ }}0.{\text{8}}0{\text{V}}\)
  • A
    \({\text{C}}{{\text{u}}^{{\text{2}} + }}\)
  • B
    \({{\text{I}}_{\text{2}}}\left( {\text{s}} \right)\)
  • C
    \({\text{A}}{{\text{g}}^ + }\)
    Correct
  • D
    \({\text{F}}{{\text{e}}^{{\text{3}} + }}\)
11
\({{\text{E}}^0}\) values of some redox couples are given below. On the basis of these values choose the correct option. \(E0values:Br2/B{r^ - } = + 1.90;Ag + /Ag(s) = + 0.80\) \(Cu2 + /Cu(s) = + 0.34;I2(s)/{l^ - } = + 0.54\)
  • A
    Cu will reduce \({\text{B}}{{\text{r}}^ - }\)
  • B
    Cu will reduce \({\text{B}}{{\text{r}}_{\text{2}}}\)
    Correct
  • C
    Cu will reduce \({{\text{l}}^ - }\)
  • D
    Cu will reduce Ag
12
Using the standard electrode potential, find out the pair between which redox reactions is not feasible. \(E0values:Fe3 + /Fe2 + = + 0.77;I2/{l^ - } = + 0.54\); \({\text{C}}{{\text{u}}^{{\text{2}} + }}/{\text{Cu }} = {\text{ }} + {\text{ }}0.{\text{34}};{\text{ A}}{{\text{g}}^ + }/{\text{Ag }} = {\text{ }} + {\text{ }}0.{\text{8}}0{\text{ V}}\)
  • A
    Ag+ and Cu
  • B
    \({\text{F}}{{\text{e}}^{{\text{3}} + }}\) and \({{\text{l}}^ - }\)
  • C
    \({\text{F}}{{\text{e}}^{{\text{3}} + }}{\text{and Cu}}\)
  • D
    \({\text{Ag and F}}{{\text{e}}^{{\text{3}} + }}\)
    Correct
13
An oxidation number of +2 is found in all their compounds of one of the below given options
  • A
    all alkali metals
  • B
    all alkaline earth metals
    Correct
  • C
    all transition elements
  • D
    superoxides
14
The oxidizing power of halogens increase in the order of
  • A
    \({\text{C}}{{\text{l}}_{\text{2}}} < {{\text{F}}_{\text{2}}} < {\text{ }}{{\text{I}}_{\text{2}}} < {\text{ B}}{{\text{r}}_{\text{2}}}\)
  • B
    \({{\text{I}}_{\text{2}}} < {\text{B}}{{\text{r}}_{\text{2}}} < {\text{C}}{{\text{l}}_{\text{2}}} < {{\text{F}}_{\text{2}}}\)
    Correct
  • C
    \({\text{B}}{{\text{r}}_{\text{2}}} < {\text{C}}{{\text{l}}_{\text{2}}} < {{\text{F}}_{\text{2}}} < {\text{ }}{{\text{I}}_{\text{2}}}\)
  • D
    \({{\text{F}}_{\text{2}}} < {{\text{I}}_{\text{2}}} < {\text{B}}{{\text{r}}_{\text{2}}} < {\text{C}}{{\text{l}}_{\text{2}}}\)
15
In which of the following compounds, an element exhibits two different oxidation states.
  • A
    \({{\text{N}}_{\text{2}}}{{\text{H}}_{\text{4}}}\)
  • B
    \({\text{N}}{{\text{H}}_{\text{4}}}{\text{N}}{{\text{O}}_{\text{3}}}\)
    Correct
  • C
    \({{\text{N}}_{\text{3}}}{\text{H}}\)
  • D
    \({\text{N}}{{\text{H}}_{\text{2}}}{\text{OH}}\)