Which of the following reactions involves the combination of two elements :- a)CaO + CO2 -> CaCO3 b)4Na + O2 -> 2Na2O c)SO2 +(1/2)O2 -> SO3 d)NH3 + HCI -> NH4CI Share with your friends Share 3 Sujeet Kumar answered this Dear student, Answer is b. As both Na and O2 are elements . Regards -3 View Full Answer Khushi Malik answered this The correct option is (b) 3
