Match each redox reaction mixture (left) with its corresponding characteristic laboratory … — JAMB UTME

Match each redox reaction mixture (left) with its corresponding characteristic laboratory observation (right).

Acidified $KMnO_4(aq)$ mixed with sulfur(IV) oxide gas ( $SO_2$ )Purple solution is decolorized to form colorless $Mn^{2+}$ ions
Acidified $K_2Cr_2O_7(aq)$ treated with iron(II) tetraoxosulfate(VI) solution ( $FeSO_4$ )Solution turns from orange to green as $Cr^{3+}$ ions form
Chlorine gas ( $Cl_2$ ) bubbled through potassium iodide solution ( $KI$ )Solution turns brown due to liberated iodine ( $I_2$ )
Hydrogen sulfide gas ( $H_2S$ ) passed into iron(III) chloride solution ( $FeCl_3$ )Yellow-brown solution turns pale green with a yellow precipitate of sulfur

Cevap

Acidified

KMnO_4

with

SO_2

changes from purple to colorless (

Mn^{2+}

); Acidified

K_2Cr_2O_7

with

FeSO_4

changes from orange to green (

Cr^{3+}

); Chlorine gas with

KI

forms brown iodine (

I_2

); Hydrogen sulfide gas with

FeCl_3

reduces

Fe^{3+}

Fe^{2+}

(pale green) with a yellow sulfur precipitate.

Each test pair matches an oxidizing or reducing reagent with its definitive qualitative laboratory test observation: permanganate decolorizes upon reduction, dichromate turns green upon reduction, iodide oxidizes to brown iodine, and iron(III) reduces to pale green iron(II) alongside yellow sulfur precipitation.

Adım Adım Çözüm

Determine the redox behavior of

SO_2

with acidified

KMnO_4

SO_2

is oxidized while reducing purple

MnO_4^-

to colorless

Mn^{2+}

Potassium permanganate test for reducing agents involves reduction of manganese from oxidation state +7 to +2.

Determine the redox behavior of

FeSO_4

with acidified

K_2Cr_2O_7

Fe^{2+}

ions oxidize to

Fe^{3+}

while

Cr_2O_7^{2-}

(orange) is reduced to

Cr^{3+}

(green).

Dichromate(VI) is a standard oxidizing agent whose reduced form contains green chromium(III) ions.

Determine the reaction of

Cl_2

with

KI

Cl_2

oxidizes colorless

I^-

ions to elemental iodine (

I_2

), turning the solution brown.

Chlorine is a stronger oxidizing agent than iodine and displaces iodide from solution.

Determine the reaction of

H_2S

with

FeCl_3

H_2S

reduces yellow-brown

Fe^{3+}

to pale green

Fe^{2+}

while forming a insoluble yellow deposit of sulfur.

Hydrogen sulfide acts as a reducing agent and deposits elemental sulfur upon oxidation.

Anahtar Kavram

Laboratory tests and characteristic color changes for oxidizing and reducing agents.

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