Question

For $25.3g$ of sodium carbonate $N{a_2}C{O_3}$ is dissolved in enough water to make $250ml$ of solution. If sodium carbonate dissociates completely molar concentration of sodium ions $N{a^ + }$ and carbonate ions are respectively (molar mass of $N{a_2}C{O_3} = 106gmo{l^{ - 1}}$ )?

Answer 1

Hint: In chemistry, concentration shows how a substance is strong or reactive. The molar concept is used to find the concentration, mass, and moles of the substance. There is a constant value of one mole that is Avogadro constant.

Complete step by step answer:
Before, calculating the concentration of sodium and carbonate ions, let's have a look at molar mass.
Molar mass - It states that the mass of a sample substance that is in grams divided by the molecular weight of the substance. It represents $M$ and its SI unit is $kg/mol$.
Molarity - It defines the concentration of the chemical substance. It measures in terms of per unit volume of solution.
Solution -It a mixture of solute and solvent. The solute is the substance dissolved in the solvent.
We have given, \[N{a_2}C{O_3} \to 2N{a^ + } + C{O_3}^{ - - }\]
Here, one mole of sodium carbonate is equal to two moles of sodium and one mole of carbonate.
molar mass $N{a_2}C{O_3}$ = $106gmo{l^{ - 1}}$
volume -$250ml$
Firstly, find the number of moles of $N{a_2}C{O_3}$
$n = \dfrac{{25.3}}{{106}} = 0.238$
When we dissociate it, we get two times sodium moles and one time carbonate.
sodium moles = $2 \times 0.238 = 0.476$
carbonate moles= $1 \times 0.238 = 0.238$
Now, find the molarity =$\dfrac{{moles\,of\,solute}}{{vol\,of\,solution}}$
molarity of sodium = $\dfrac{{0.476}}{{250 \times {{10}^{ - 3}}}}$ =$1.910M$
molarity of carbonate = $\dfrac{{0.238}}{{250 \times {{10}^{ - 3}}}}$ =$0.955M$
Therefore, the concentration of sodium and carbonate ions are $1.910M$and $0.955M$.

Note:
The solution has two types that are Homogeneous solution and Heterogeneous solution. Homogeneous - A solution in a fixed ratio or composition is known as homogeneous. Heterogeneous - A solution is not in a fixed ratio or composition that is known as the heterogeneous solution. The common unit of molarity is mol per liter.