The Selenium is the element that is likely to be the most brittle
Ph = A
Acid = C
Base = D
Litmus paper = B
Term = ?
Explanation:
As the given chemical reaction equation is as follows.

Also, it is given that for 2 moles the energy required is 130 kcal. This means that energy required for 1 mole is calculated as follows.
1 mole = 
= 65 kcal
Hence, energy required for 7 moles will be calculated as follows.
Energy required = 
= 455 kcal
Thus, we can conclude that energy required to produce 7.00 mol
on the basis of given reaction is 455 kcal.
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