Question

How can I measure the concentration of salt in water?

Answer 1

Hint: As we know that a salt is formed only when an acid and a base are combined. We also know that when salt is dissolved in water it forms a solution and we also know the concept of molarity and molality of a solution which can help in finding the weight of a given salt.

Complete answer:
We are well aware of the term salt and it is basically a product of a combination of acid and base. Now there are two ways by which we can measure the concentration of salt in water forming a solution. One of them is using molarity which can be calculated by the ratio of moles of salt to the volume in litres of a solution.

The formula is given as:
$Molarity = \dfrac{{mass \times 1000}}{{molecular{\text{ }}mass \times Vol(ml)}}$
For instance: We have common salt which is sodium chloride $(NaCl)$, we can find out its concentration by knowing the mass of sodium chloride, volume of solution and we already know its molecular mass and thus the molarity or concentration of salt can be identified.

Similarly, we can measure the concentration of salt with the help of a second term called molality which is calculated by the ratio of moles of salt to the weight of solution in kilograms. The formula for molality is given as:
$Molality = \dfrac{{mass}}{{molecular{\text{ }}mass \times mass{\text{ }}of{\text{ }}solute(Kg)}}$
Therefore, from the above explanation we can say that the correct answers are Molarity and molality of a solution gives us the concentration of any salt dissolved in water.

Note: Always remember that a solution of $1$ molar concentration is a bit more concentrated that a solution of $1$ molal concentration and the reason behind this is because $1$ litre of $1$ molar solution contains $1$ mole of sodium chloride which are dissolved in $1$ litre of salt water solution.