A.22%                 B.32%                 C.19.56%              D.2%

由乙炔、苯和乙醛組成的混合物，經(jīng)測定其中碳的質(zhì)量分?jǐn)?shù)為72%，則氧的質(zhì)量分?jǐn)?shù)為（    ）

A.22%             B.32%              C.19.56%          D.2%

A.20.7%             B.22%               C.24.9%             D.28%

由乙炔、苯和甲醛組成的混合物，經(jīng)測定其中含碳的質(zhì)量分?jǐn)?shù)為72%，則含氧的質(zhì)量分?jǐn)?shù)是

1. A.
   22%
2. B.
   24.9%
3. C.
   28%
4. D.
   20.7%