Removing chloride ion is the reaction away
An electron shifts from a lower energy to a higher energy
Covalent network. <span>A solid that is extremely hard, that has a very high melting point, and that will not conduct electricity either as a solid or when molten is held together by a continuous three-dimensional network of covalent bonds. Examples include diamond, quartz (SiO </span><span>2 </span>), and silicon carbide (SiC). The electrons are constrained in pairs to a region on a line between the centers of pairs of atoms.<span>
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If electronegativity difference between atoms is much higher then they form ionic bond.
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Answer : Half reaction is defined as the reaction which will be <span>either the oxidation or reduction </span>reaction<span> of particular species in a given redox </span>reaction<span>.
So as per the definition in the reaction of,
</span>

<span>
</span>

<span>
here on left and right side </span>

will get cancelled.
and we will get,

Here,

...this is oxidation reaction as Ba is getting reduced to

by losing 2 electrons.
whereas,on the other hand,

...this is reduction reaction as

is getting reduced to Zn by gaining 2 electrons.