Question

Which of the following is a synthesis reaction?

C2H4 + 3O2 yields 2CO2 + 2 H2O

2HCl yields H2 + Cl2

2K + 2HCl yields 2KCl + H2

SO3 + H2O yields H2SO4

Answer 1

the last one is the answer to your question. D is the answer

Answer 2

SO3+H2O yields H2SO4 is the correct answer for your question, WELCOME:)