Question

What is the molecular formula of fructose if its molar mass is $180.g/mol$, and its empirical formula is $C{H}_{2}O$?

• A. $C_3{H}_6{O}_3$
• B. $C_4{H}_4{O}_8$
• C. $C_6{H}_{12}{O}_6$
• D. $C_8{H}_{10}{O}_8$

Answer 1

Answer: (C)

$C_6{H}_{12}{O}_6$

Let the molecular formula of Fructose $=(C{H}_{2}O{)}_n=C_n{H}_{2n}{O}_n$

So, the molecular mass of Fructose, $180g/mol=n\times [12+2+16]$

$\Rightarrow n\times 30=180$

$\Rightarrow n=6$

So, the molecular formula $=C_6{H}_{12}{O}_6$