Answer:
Chromium
Explanation:
Cr has 24 atomic number and mass number 52
Hydrogen gas is produced when dilute hydrochloric acid is added to a reactive metal.
Balanced molecular equation of sodim metal with hydrochloric acid:
2Na(s) + 2HCl(aq) → 2NaCl(aq) + H₂(g).
Ionic equation: 2Na(s) + 2H⁺(aq) + 2Cl⁻(aq) → 2Na⁺ + 2Cl⁻(aq) + H₂(g).
Net ionic equation: 2Na(s) + 2H⁺(aq) → 2Na⁺(aq) + H₂(g).
Sodium is oxidized from oxidation number 0 (Na) to oxidation number +1, hydrogen is reduced from oxidation number +1 to oxidation number 0 (hydrogen gas H₂).
Another example:
Balanced chemical equation: Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)
Word equation: zinc + hydrochloric acid → zinc chloride + hydrogen gas
More about hydrogen gas:brainly.com/question/24433860
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<u>Any of five chemical substances that are not metals and that combine with hydrogen to form strong acid compounds from which simple salts can be made</u>
Answer:
A = 2A + 3B → 5C
Explanation:
The two molecule of A and three molecules of B will react to form the five molecules of C.
2A + 3B → 5C
Other options are incorrect because,
B = A₂ + B₃ → C₅
in this reaction one molecule of A₂ and one molecule of B₃ combine to form one molecule of C₅.
C = 2A + 5B → 3C
in this reaction two molecules of A and five molecules of B combine to form three molecule of C.
D = A₂ + B₃ → C₃
in this reaction one molecule of A₂ and one molecule of B₃ combine to from one molecule of C₃.
