6 HCl (aq) + K2Cr2O7 (aq) + 4 Na2SO3 (aq) 3 H2O (l) + 2 KCl (aq) + 4 Na2SO4 (aq) + 2 CrCl2 (aq)

This is an acid-base reaction (neutralization): HCl is an acid, Na2SO3 is a base.

This is an oxidation-reduction (redox) reaction:

4 SIV - 8 e- 4 SVI (oxidation)

2 CrVI + 8 e- 2 CrII (reduction)

Na2SO3 is a reducing agent, K2Cr2O7 is an oxidizing agent.

Reactants:

  • HClChlorane source: wikipedia, accessed: 2019-09-27, Hydrogen chloride source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02
    • Other names: Hydrochloric acid source: wikipedia, accessed: 2019-09-27source: NIOSH NPG, accessed: 2019-09-02, Hydrochloric acid gas source: wikipedia, accessed: 2019-09-27, HCl source: wikidata, accessed: 2019-09-02
    • Appearance: Colorless, transparent liquid, fumes in air if concentrated source: wikipedia, accessed: 2019-09-27; Colorless gas source: wikipedia, accessed: 2019-09-27; Colourless compressed liquefied gas with pungent odour source: ICSC, accessed: 2019-09-04; Colorless to slightly yellow gas with a pungent, irritating odor. [Note: Shipped as a liquefied compressed gas.] source: NIOSH NPG, accessed: 2019-09-02
  • K2Cr2O7Potassium 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
  • Na2SO3Sodium sulfite source: wikipedia, accessed: 2019-09-28source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Other names: Sodium sulphite source: wikipedia, accessed: 2019-09-28source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Hypo clear (photography) source: wikipedia, accessed: 2019-09-28, E221 source: wikipedia, accessed: 2019-09-28
    • Appearance: White solid source: wikipedia, accessed: 2019-09-28; White crystals or powder source: ICSC, accessed: 2019-09-04

Products:

  • H2OWater, 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
  • KCl
    • Names: Potassium chloride source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Sylvite source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Muriate of potash source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Appearance: White crystalline solid source: wikipedia, accessed: 2019-09-27; Colourless hygroscopic crystals source: ICSC, accessed: 2019-09-04
  • Na2SO4
    • Names: Sodium sulfate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Sodium sulphate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Sulfate of sodium source: wikipedia, accessed: 2019-09-27
    • Appearance: White crystalline solid | hygroscopic source: wikipedia, accessed: 2019-09-27; White hygroscopic solid in various forms source: ICSC, accessed: 2019-09-04
  • CrCl2Chromium(II) chloride source: wikipedia, accessed: 2019-09-27source: ICSC, accessed: 2019-09-04
    • Other names: Chromous chloride source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Chromium dichloride source: ICSC, accessed: 2019-09-04
    • Appearance: White to grey/green powder (anhydrous), very hygroscopic source: wikipedia, accessed: 2019-09-27; Very hygroscopic solid in various forms source: ICSC, accessed: 2019-09-04