Question Video: Identifying the Chemical Equation That Describes the Reaction of Scandium and Water Chemistry • Third Year of Secondary School

Name: Identifying the Chemical Equation That Describes the Reaction of Scandium and Water
Uploaded: 2021-08-30

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Finely divided particles of scandium metal reacts vigorously with water. Which of the following chemical equations correctly describes this reaction? [A] 2Sc (s) + 4H₂O (l) → 2Sc(OH)₂ (aq) + 2H₂ (g) [B] Sc (s) + 3H₂O (l) → H₂ScO₃ (aq) + 2H₂ (g) [C] Sc (s) + H₂O (l) → ScO (s) + H₂ (g) [D] 2Sc (s) + 6H₂O (l) → 2Sc(OH)₃ (aq) + 3H₂ (g) [E] 2Sc (s) + 3H₂O (l) → Sc₂O₃ (s) + 3H₂ (g)

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Video Transcript

Finely divided particles of scandium metal reacts vigorously with water. Which of the following chemical equations correctly describes this reaction? (A) Two Sc solid plus four H2O liquid reacts to produce two Sc(OH)2 aqueous plus two H2 gas. (B) Sc solid plus three H2O liquid reacts to produce H2ScO3 aqueous plus two H2 gas. (C) Sc solid plus H2O liquid reacts to produce ScO solid plus H2 gas. (D) Two Sc solid plus six H2O liquid reacts to produce two Sc(OH)3 aqueous plus three H2 gas. Or (E) two Sc solid plus three H2O liquid reacts to produce Sc2O3 solid plus three H2 gas.

When scandium particles react with water, they undergo oxidation and form scandium(III) hydroxide. Scandium loses all three of its valence electrons and gets a three plus charge state and bonds with hydroxide ions in water. The remaining hydrogen atoms combine and form hydrogen gas. Finely divided particles of scandium metal react vigorously with water. The reaction releases a lot of thermal energy in a short amount of time. Many but not all metals share this property. The solid metal elements undergo an oxidation reaction when placed in water.

All of the options from (A) to (E) show scandium reacting with water to produce hydrogen. But the other product for each answer choice is different. We know the correct product to be scandium(III) hydroxide. Answer choices (A) and (D) have the product scandium hydroxide. But only answer choice (D) has the product scandium(III) hydroxide. So the chemical equation that correctly describes the reaction of scandium metal and water is (D). Two Sc solid plus six H2O liquid reacts to produce two Sc(OH)3 aqueous plus three H2 gas.