Question

C+O₂$\to$CO₂ The above reaction is a ____________ reaction.

• A. combination
• B. decomposition
• C. displacement
• D. double displacement

Answer 1

The correct option is A

combination

• Chemical reactions are mainly classified into four, combination reaction, decomposition reaction, displacement reaction and double displacement reaction.
• In a combination reaction, two or more substances combine to form a new single substance.
• eg: 2 H₂ (g)+ O₂ (g)$\to$ 2H₂O (l)

• Explanation for correct answer
• Carbon combines with oxygen form carbon dioxide.
• A chemical reaction in which two or more reactants combine to form single product is called combination reaction.
• Therefore C (s) +O₂ (g)$\to$CO₂ (g) is a combination reaction.

• Explanation for incorrect answer
• In a decomposition reaction, a single reactant decomposes to give two or more substances.
• CaCO₃ (s)$\to$CaO(s) +CO₂ (g)
• In a displacement reaction, one element displaces another element from its compound.
• Fe₂O₃ (s) +2Al (s) l$\to$Al₂O₃ (s) + 2Fe (s)
• In a double displacement reaction, the radicals are interchanged.
• NaCl (aq) +AgNO₃(aq)$\to$AgCl (s) + NaNO₃ (aq)

Hence option (a) is the correct option.