3 H2SO4 + 2 Cr → Cr2(SO4)3 + 3 H2

This is an oxidation-reduction (redox) reaction:

6 HI + 6 e- → 6 H0 (reduction)

2 Cr0 - 6 e- → 2 CrIII (oxidation)

H2SO4 is an oxidizing agent, Cr is a reducing agent.

Reactants:

  • 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
  • Cr
    • Names: Chromium source: wikidata, accessed: 2019-09-07source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, Chromium metal source: NIOSH NPG, accessed: 2019-09-02, Cr source: wikidata, accessed: 2019-09-07
    • Appearance: Grey powder source: ICSC, accessed: 2019-09-04; Blue-white to steel-gray, lustrous, brittle, hard, odorless solid. source: NIOSH NPG, accessed: 2019-09-02

Products:

  • 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
  • H2
    • Names: Dihydrogen source: wikidata, accessed: 2019-09-07, Hydrogen source: ICSC, accessed: 2019-09-04source: wikidata, accessed: 2019-09-07, H2 source: wikidata, accessed: 2019-09-07
    • Appearance: Odourless colourless compressed gas source: ICSC, accessed: 2019-09-04