Question

0.0833 mol of carbohydrate of empirical formula ${CH}_{2}O$ contain 1 g of hydrogen. The molecular formula of carbohydrate is:

• A. ${C_{5}H}_{10}{O}_5$
• B. ${C_{6}H}_{12}{O}_6$
• C. ${C_{12}H}_{22}{O}_{11}$
• D. ${C_{3}H}_4{O}_3$

Answer 1

Answer: (B)

${C_{6}H}_{12}{O}_6$

Let the molecular formula of the carbohydrate be equal to $(C{H}_{2}O{)}_n$

In 1 mole of carbohydrate, there is $2n\times 1=2ng$ of hydrogen present
So, 0.0833 mole of carbohydrate there is $2n\times 0.0833g$ of hydrogen which is equal to $1g$

$2n\times 0.0833=1$

$\therefore n=6$
So, the molecular formula of the carbohydrate will be $(C{H}_{2}O{)}_n=(C{H}_{2}O{)}_6=C_6{H}_{12}{O}_6$