Question

The number of hydrogen atoms present in $25.6$ g of sucrose $\left(C_{12}{H}_{22}{O}_{11}\right)$ which has a molar mass of $342.3$g is;

• A. $22\times {10}^{23}$
• B. $9.91\times {10}^{23}$
• C. $11\times {10}^{23}$
• D. $44\times {10}^{23}$

Answer 1

The correct option is B $9.91\times {10}^{23}$

Number of moles of sucrose = $\frac{Givenmass}{Molarmass}=\frac{25.6}{342.3}=0.074$ mol

Number of sucrose molecules in 1 mol = $6.022\times {10}^{23}$

Number of sucrose molecules in 0.074 mol = $6.022\times {10}^{23}\times 0.074=4.503\times {10}^{22}$

Number of hydrogen atoms in 1 molecule of sucrose = 22

Therefore, Number of hydrogen atoms in $4.503\times {10}^{22}$ molecules = $22\times 4.503\times {10}^{22}$ = $9.91\times {10}^{23}$