Question

Find the molecular mass of table sugar (sucrose) which has a molecular formula ${C_{12}}{H_{22}}{O_{11}}$.
A.$340$
B.$242.30$
C.$342.30$
D.None of these

Answer 1

Sucrose is disaccharide and obtained naturally from plants and after refining it gets converted to table sugar. Molecular mass of sucrose can be calculated by using the molecular mass of all the atoms present in the molecule and summing up which gives the molecular mass of the whole compound. Also, Molecular mass of Carbon, Hydrogen and Oxygen are $12.01,{\text{ }}1.008,{\text{ }}and{\text{ }}16.0$

Complete step by step answer:
In the question, the molecular mass of sucrose needs to be calculated and sucrose is also known as table sugar which is a disaccharide and it is obtained naturally from plants and then refined to make table sugar. In its structure it contains glucose and fructose both present in equal amounts and makes sucrose finally.
Molecular formula of Sucrose is ${C_{12}}{H_{22}}{O_{11}}$ and therefore, Carbon, Hydrogen and Oxygen are present in it.
Now we have to find the molecular mass of sucrose and molecular mass is defined as the mass in the atomic mass unit of all the atoms present in the given molecule. It is commonly referred to as molecular weight.
So, in the molecular formula of Sucrose, 12 carbon atoms are present and the mass of each carbon atom is $12.01$and similarly mass of each Hydrogen atom = $1.008$and mass of Oxygen atom = $16.0$
So, mass of sucrose = $12 \times \left( {12.01} \right) + 22 \times \left( {1.008} \right) + 11 \times \left( {16} \right)$
$\Rightarrow 144.12{\text{ }} + {\text{ }}22.176{\text{ }} + {\text{ }}176$
$\Rightarrow 342.296$
$\sim 342.30$

So, the correct answer is C i.e. $342.30$

Note:
Sucrose contains glycosidic bonds in which glucose and fructose are present and when hydrolysis of sucrose occurs, it gets breakdown into Glucose and Fructose. These are also similar carbohydrate compounds but they have different molecular formulas and structure. Glucose has molecular formula of ${C_6}{H_{12}}{O_6}$ and Fructose has molecular formula of ${C_6}{H_{12}}{O_6}$ but has different structure and functional group in it.