Question

which of the following chemical reactions produces water via a synthesis reaction?
a 2h₂ + o₂ → 2h₂o
b cuo + h₂ → cu + h₂o
c naoh + hcl → nacl + h₂o
d h₂co₃ → co₂ + h₂o

Explanation:

A synthesis reaction is a reaction where two or more reactants combine to form a single product.

• In option a: \(2H_2 + O_2

ightarrow2H_2O\), two reactants (\(H_2\) and \(O_2\)) combine to form one product (\(H_2O\)), which is a synthesis reaction.

• In option b: \(CuO + H_2

ightarrow Cu + H_2O\), it is a single - displacement reaction (hydrogen displaces copper from copper oxide).

• In option c: \(NaOH + HCl

ightarrow NaCl + H_2O\), it is a double - displacement (acid - base neutralization) reaction.

• In option d: \(H_2CO_3

ightarrow CO_2 + H_2O\), it is a decomposition reaction (one reactant breaks down into two products).

Answer:

A. \(2H_2 + O_2
ightarrow2H_2O\)