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Chand Anees Kannan
Asked: 2022-11-10T20:09:13+05:30 In:

Oxidation reaction involves loss of electrons, and reduction reaction involves gain of electrons. The reaction in which a species disproportinates into two oxidation states ( lower and higher) is called disproportionation reaction.
Which of the following statements is correct?
A. An element in the lowest oxidation state acts only as a reducing agent.
B. An element in the highest oxidation state acts only as a reducing agent.
C. The oxidation number of `V` is `Rb_(4)K(HV_(10)O_(28)) is +4`.
D. The oxidation number and valency of `Hg` in calomel is `+1`

Oxidation reaction involves loss of electrons, and reduction reaction involves gain of electrons. The reaction in which a species disproportinates into two oxidation states ( lower and higher) is called disproportionation reaction.
Which of the following statements is correct?
A. An element in the lowest oxidation state acts only as a reducing agent.
B. An element in the highest oxidation state acts only as a reducing agent.
C. The oxidation number of `V` is `Rb_(4)K(HV_(10)O_(28)) is +4`.
D. The oxidation number and valency of `Hg` in calomel is `+1`
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  1. Correct Answer – A
    a. An element in the lowest oxidation state can only attain higher oxidation state. So it is a reductant and undergoes oxidation.
    b. An element in the highest oxidation state only attain lower oxidation state. So it si an oxidant and undergoes reduction.
    c. The oxidation state of `Rb` and `K` is `+1` ( first group element)
    `overset(+1xx4+1)(Rb_(4)K(HV_(10)O_(28))^(-5)`
    `HV_(10)O_(28)^(-5)=1+10x-2xx28= -5`
    d. Calomel is `overset(+1xx2-1xx2)(Hg_(2)+Cl_(2))`
    The oxidation number of `Hg` is `+1` and valency is `2`.

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Parveen Garg
Asked: 2022-11-07T20:05:45+05:30 In:

Oxidation reaction involves loss of electrons, and reduction reaction involves gain of electrons. The reaction in which a species disproportinates into two oxidation states ( lower and higher) is called disproportionation reaction.
Which of the following statements is wrong?
A. The algebraic sum of the oxidation numbers of all atoms in an iron is zero.
B. The oxidation number is an arbitrary number. It can have positive, negative, zero, or fractional values.
C. When a negative ion changes to neutral species, the process is oxidation.
D. The oxidation number of phosphorous can very from `-3 t o +5`.

Oxidation reaction involves loss of electrons, and reduction reaction involves gain of electrons. The reaction in which a species disproportinates into two oxidation states ( lower and higher) is called disproportionation reaction.
Which of the following statements is wrong?
A. The algebraic sum of the oxidation numbers of all atoms in an iron is zero.
B. The oxidation number is an arbitrary number. It can have positive, negative, zero, or fractional values.
C. When a negative ion changes to neutral species, the process is oxidation.
D. The oxidation number of phosphorous can very from `-3 t o +5`.
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  1. Correct Answer – A
    a. Wrong: The algebraic sum of the oxidation numbers of all the atoms in an ion equals the charge present on the ion.
    b. True statement
    c. True `(2Cl^(ө)rarrCl_(2)+2e^(-))`(oxidation)
    True

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Ujwal Bedi
Asked: 2022-11-06T23:57:34+05:30 In:

Oxidation reaction involves loss of electrons, and reduction reaction involves gain of electrons. The reaction in which a species disproportinates into two oxidation states ( lower and higher) is called disproportionation reaction.
Which of the following statements is wrong?
A. An acidified `K_(2)Cr_(2)O_(7)` paper on being exposed to `SO_(2)` turns green.
B. Mercuric chloride and stannous chloride cannot exist as such.
C. Iron turning on addition to `CuSO_(4)` solution decolourises the blue colour.
D. `[CuI_(4)]^(2-)` is formed but `[CuCl_(4)]^(2-)` is not.

Oxidation reaction involves loss of electrons, and reduction reaction involves gain of electrons. The reaction in which a species disproportinates into two oxidation states ( lower and higher) is called disproportionation reaction.
Which of the following statements is wrong?
A. An acidified `K_(2)Cr_(2)O_(7)` paper on being exposed to `SO_(2)` turns green.
B. Mercuric chloride and stannous chloride cannot exist as such.
C. Iron turning on addition to `CuSO_(4)` solution decolourises the blue colour.
D. `[CuI_(4)]^(2-)` is formed but `[CuCl_(4)]^(2-)` is not.
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  1. Correct Answer – D
    a. `Cr_(2)O_(7)^(2-)` (orange red) oxidises `SO_(2)` to `SO_(4)^(2-)` and is itself reduced to `Cr^(+3)` (green).
    `underset((“Orange”))(Cr_(2)O_(7)^(2-)+3H^(o+)+3SO_(2))rarrunderset((“Green”))(2Cr^(3+)+3SO_(4)^(2-)+4H_(2)O`
    b. Both reacts together
    `overset(+2)(Hg)Cl_(2)+overset(+2)(SnCl_(2))rarroverset(+1)underset((“White ppt”))(HgCl_(2))darr+overset(+4)(SnCl_(4))`
    `overset(+1)(Hg_(2))Cl_(2)+overset(+2)(SnCl_(2))rarrunderset((Grey))(2Hg)darr+overset(+4)(SnCl_(4))`
    c. `overset(0)Fe+underset((Blue))overset(+22)(CuSO_(4))rarrFe^(2+)+overset(0)(Cu)`
    d. `[CuCl_(4)]^(2-)` is formed but `[CuI_(4)]^(2-)` is not.
    `I^(ө)`ion reduces `Cu^(2+)` to `overset(+1)(Cul)` and itself undergoes oxidation to form `I_(2)`. However, `CI^(ө)` does not reduce `Cu^(2+)`.

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