ANS:D - molarity

The most convenient way of expressing solution concentration depends on the specific application and the properties of the substances involved. However, among the options provided, the most commonly used and convenient way of expressing solution concentration is in terms of molarity. Molarity (M) is defined as the number of moles of solute dissolved per liter of solution. It is widely used in laboratory experiments, chemical reactions, and industrial processes due to its simplicity and ease of measurement. Molarity allows for straightforward calculations and is particularly useful when dealing with aqueous solutions where volume measurements are practical. While mole fraction, normality, and molality are also used to express solution concentration in various contexts, they may not always be as convenient or as widely applicable as molarity.