A gas diffuses one-thrid as fast as O_(2) at 100^(@)C. This gas could

1.	A gas diffuses one-thrid as fast as O_(2) at 100^(@)C. This gas could be:
Answer» He(M=4) `C_(2)H_(5)(M=48)` `C_(7)H_(12)(M=96)` `C_(5)F_(12)(M=288)` ANSWER :d

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