Question

K2cr2o7+kI+h2so4=k2so4+cr2(so4)3+I2+H2O which lose electron and which gain electron

Answer 1

K2Cr2O7 + 6 KI + 7 H2SO4 → 4 K2SO4 + Cr2(SO4)3 + 3 I2 + 7 H2O

This is an oxidation-reduction (redox) reaction:

6 I-I - 6 e- → 6 I0

(oxidation)

2 CrVI + 6 e- → 2 CrIII

(reduction)

KI is a reducing agent, K2Cr2O7 is an oxidizing agent.

Reactants:

K2Cr2O7 – Potassium dichromate(VI) source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02

Other names: Potassium dichromate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Chromium potassium oxide source: wikidata, accessed: 2019-09-02, Dipotassium dichromium heptaoxide source: wikidata, accessed: 2019-09-02

Appearance: Red-orange crystalline solid source: wikipedia, accessed: 2019-09-27; Orange-to-red crystals source: ICSC, accessed: 2019-09-04

KI

Names: Potassium iodide source: wikidata, accessed: 2019-09-02, KI source: wikidata, accessed: 2019-09-02, Thyrosafe source: wikidata, accessed: 2019-09-02

H2SO4 – Sulfuric acid source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-07source: NIOSH NPG, accessed: 2019-09-02

Other names: Oil of vitriol source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-07source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, Sulfuric acid, concentrated (> 51% and < 100%) source: ICSC, accessed: 2019-09-04, H2SO4 source: wikidata, accessed: 2019-09-07

Appearance: Clear, colorless liquid source: wikipedia, accessed: 2019-09-27; Odourless colourless oily hygroscopic liquid source: ICSC, accessed: 2019-09-04; Colorless to dark-brown, oily, odorless liquid. [Note: Pure compound is a solid below 51°F. Often used in an aqueous solution.] source: NIOSH NPG, accessed: 2019-09-02

Products:

K2SO4

Names: Potassium sulfate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Potassium sulphate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Dipotassium sulfate source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04

Appearance: White solid source: wikipedia, accessed: 2019-09-27; Colourless-to-white crystals source: ICSC, accessed: 2019-09-04

Cr2(SO4)3 – Chromium(III) sulfate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02

Other names: Basic chromium sulfate source: wikipedia, accessed: 2019-09-27, Chromic sulfate source: wikipedia, accessed: 2019-09-27

Appearance: Reddish-brown crystals (anhydrous), purple crystals (hydrated) source: wikipedia, accessed: 2019-09-27

I2

Names: Iodine source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, Jod source: ICSC, accessed: 2019-09-04, Iode source: ICSC, accessed: 2019-09-04

Appearance: Bluish black or dark purple crystals with pungent odour source: ICSC, accessed: 2019-09-04; Violet solid with a sharp, characteristic odor. source: NIOSH NPG, accessed: 2019-09-02

H2O – Water, oxidane source: wikipedia, accessed: 2019-09-27

Other names: Water (H2O) source: wikipedia, accessed: 2019-09-27, Hydrogen hydroxide (HH or HOH) source: wikipedia, accessed: 2019-09-27, Hydrogen oxide source: wikipedia, accessed: 2019-09-27

Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas source: wikipedia, accessed: 2019-09-27

Search by reactants (K2Cr2O7, KI, H2SO4)

1 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + I2 + Cr2(SO4)3

2 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + I2 + Cr2(SO4)

3 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + I2 + Cr2(SO4)2

4 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + Cr2(SO4)3 + KIO3

5 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + I2 + Cr2(SO4)3 + K2CrO4

6 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + I2 + Cr2(SO3)3

7 H2SO4 + K2Cr2O7 + KI → H2O + I2 + Cr2(SO4)3 + K2(SO4)

8 H2SO4 + K2Cr2O7 + KI → H2O + I2 + K2CrO4 + Cr2(SO4)

9 H2SO4 + K2Cr2O7 + KI → H2O + I2 + Cr2(SO4)3 + KHSO4

10 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + Cr2(SO4)3 + HIO3

Search by products (K2SO4, Cr2(SO4)3, I2, H2O)

12

1 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + I2 + Cr2(SO4)3

2 H2SO4 + K2Cr2O7 + HI → H2O + K2SO4 + I2 + Cr2(SO4)3

3 H2SO4 + K2Cr2O7 + NaI → H2O + K2SO4 + I2 + Na2SO4 + Cr2(SO4)3

4 H2SO4 + KI + K2CrO4 → H2O + K2SO4 + I2 + Cr2(SO4)3

5 H2SO4 + KI + Na2Cr2O7 → H2O + K2SO4 + I2 + Na2SO4 + Cr2(SO4)3

6 H2SO4 + KI + (NH4)2Cr2O7 → H2O + K2SO4 + I2 + Cr2(SO4)3 + (NH4)SO4

7 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + I2 + Cr2(SO4)3 + K2CrO4

8 H2SO4 + KI + KCr2O7 → H2O + K2SO4 + I2 + Cr2(SO4)3

9 H2SO4 + KI + (NH4)2Cr2O7 → H2O + K2SO4 + I2 + Cr2(SO4)3 + (NH4)2SO4

10 H2SO4 + NaI + K2CrO4 → H2O + K2SO4 + I2 + Na2SO4 + Cr2(SO4)3

12

Search by reactants (K2Cr2O7, KI, H2SO4) and by products (K2SO4, Cr2(SO4)3, I2, H2O)

1 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + I2 + Cr2(SO4)3

2 H2SO4 + K2Cr2O7 + KI → H2O + K2SO4 + I2 + Cr2(SO4)3 + K2CrO4

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© Michal Punčochář