Question

A solution of glucose in water is labelled as$10\% w/w$. What would be the molarity of the solution?

Answer 1

We need to know that in chemistry, the concentration of the solution is very important. The strength of the solution is very important for inhale solution and medicinal chemistry. There are different ways of representing the concentration of solutions. There are molality, molarity, normality formality, mole fraction, mass percentage, volume percentage, mass by volume and parts per million.
Formula used:
The molarity of the solution depends on the number moles of the solute and the volume of the solution in litres. The molarity of the solution is equal to the ratio of the number of moles of the solute to the volume of the solution in litres. The symbol of molarity is M.
${\text{Molarity = }}\dfrac{{{\text{number of moles of the solute}}}}{{{\text{volume of the solution litre}}}}$
Moles are defined as the given mass of the molecule is divided by the molecular mass of the molecule.
${\text{moles}}{\text{ = }}\dfrac{{{\text{mass}}{\text{ofthe}}{\text{molecule}}}}{{{\text{molecular weight of the molecule}}}}$
The molecular weight of the molecule is dependent on the atomic weight of the atom present in the molecule. The molecular weight of the molecule is equal to the sum of the molecular weight of the atom and the number of the respective atom in the molecule.
$Molecular Weight$ = $Number of the atoms \times Atomic Weight Of The Atom$

Complete answer:
The given data is
A solution of glucose in water is labelled as $10\% w/w$. That means for a $100g$ solution $90$ gram of water and $10$ gram of glucose.
The molecular weight of glucose is$180$.
The molecular weight of water is $18$.
We calculate the moles of water in the given solution,
${\text{moles}}{\text{ = }}\dfrac{{{\text{mass}}{\text{ofthe}}{\text{molecule}}}}{{{\text{molecular weight of the molecule}}}}$
Now we can substitute the known values and on simplification we get,
$= \dfrac{{90}}{{18}} = 5 moles$
We calculate the moles of glucose in the given solution,
${\text{moles}}{\text{ = }}\dfrac{{{\text{mass}}{\text{ofthe}}{\text{molecule}}}}{{{\text{molecular weight of the molecule}}}}$
Now we can substitute the known values and on simplification we get,
$= \dfrac{{10}}{{80}} = 0.0555moles$
The moles of glucose in the given solution is $0.0555moles$.
The volume of the given solution $100$
We calculate the molarity of the solution is ,
${\text{Molarity = }}\dfrac{{{\text{number of moles of the solute}}}}{{{\text{volume of the solution litre}}}}$
Now we can substitute the known values and on simplification we get,
$= \dfrac{{0.0555}}{{0.090}} = 0.667m$
According to the above discussion, we conclude the molarity of the solution is $0.667m$.

Note:
We need to know that glucose is a well known and simplest example for carbohydrates. The chemical formula of glucose is ${{\text{C}}_{\text{6}}}{{\text{H}}_{{\text{12}}}}{{\text{O}}_{\text{6}}}$. The simplest representation of the glucose molecule is${{\text{(C}}{{\text{H}}_{\text{2}}}{\text{O)}}_6}$.The glucose is one of the important substance in our body. Glucose plays a key role in brain fuel, muscle fuel, other tissue fuel, maintaining our body structure and helps to prevent hypoglycemia and hyperglycemia. It extracts our body from foods, glycogen to glucose by using our salvia. Our saliva is acidic in nature due to hydrochloric acid being secreted in our body.