Question

The bond energy of $H_2$ is 104.3K.cal mol${}^{-1}$ . It means that

• A. 104.3K.cal heat is needed to break up N bonds in N molecules of $H_2$
• B. 104.3K.cal heat is needed to break up $6.023\times {10}^{23}$ molecules into $1.2406\times {10}^{24}$atoms of H
• C. 104.3K.cal heat is evolved during combination of 2N atoms of H to form N molecules of $H_2$
• D. None of these

Answer 1

The correct option is B 104.3K.cal heat is needed to break up $6.023\times {10}^{23}$ molecules into $1.2406\times {10}^{24}$atoms of H

Bond energy of H${}_2$ is 104.3 Kcal mol${}^{-1}$ means to read H - H bond of 1 mole of H${}_2$, 104.3 Kcal heat will be released.