Question

Which of the following displaces Oxygen from Water?
A. \[{F_2}\]
B. \[C{l_2}\]
C. \[B{r_2}\]
D. \[{I_2}\]

Answer 1

Hint: The elements given in the options are all halogens belonging to the group \[17\]. To find out with which molecule water will react one must be familiar with the trends in the group as well as halogen’s properties.

Complete answer:
Halogens belongs to Group \[17\] . They precedes the noble gas family and are non-metals. As we know that elements belonging to a group have similar outer electronic configuration are arranged in the group. So we can say that all these options given have similar valence electrons. Also the halogens have high negative electron enthalpy and the metallic character increases as we move down the group. They readily accept one electron to attain the stable noble gas electronic configuration.
Oxidising agents or oxidisers are the substance that has the ability to oxidise other substances. They readily accept electrons. In other words we can also say that oxidising agents increase the oxidation state of the substance by making other species lose electrons. As we have stated earlier that halogens accept electrons readily therefore they are oxidising agents. They also have low energy of dissociation, high electron affinity and higher hydration of its ion. All these properties contribute to halogens' high oxidising power.
Now out of these options one must select the strongest oxidising agents among them which is \[{F_2}\] and therefore displaces Oxygen from Water. Since \[{F_2}\] is more electronegative in nature therefore attracts shared electrons more than the other halogens. Electronegativity decreases as we move down the group.

Note:
Another reason for \[{F_2}\] being the strongest oxidising agent is that it has high hydration energy of its ion as well as more readily loses the electrons therefore have higher reduction potential. Therefore \[{F_2}\] acts as a strong oxidising agent.