Question

The normality of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) having 50 milliequivalent in \(2 \mathrm{~L}\) solution is: (a) \(1.025\) (b) \(1.25\) (c) \(0.050\) (d) \(0.025\)

Short answer

The normality of the solution is 0.025.

Step-by-step solution

Understand Normality

Normality is defined as the number of equivalents of solute per liter of solution. It is a measure of concentration equivalent to molarity, but accounts for the reactive capacity of the solute.

Calculate the Number of Equivalents

The problem states there are 50 milliequivalents (meq) of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) in the solution. To find the number of equivalents, convert milliequivalents to equivalents:\[50 \text{ meq} = \frac{50}{1000} \text{ equivalents} = 0.05 \text{ equivalents}\]

Apply the Normality Formula

Now, use the formula for normality: \[\text{Normality (N)} = \frac{\text{Equivalents}}{\text{Volume of solution in L}}\]The solution volume is given as 2 liters. Plug in the values:\[\text{Normality (N)} = \frac{0.05}{2} = 0.025 \text{ N}\]

Choose the Correct Answer

After calculating, the normality of the solution is 0.025 N. Comparing to the choices given: (a) 1.025 (b) 1.25 (c) 0.050 (d) 0.025 The correct option is (d) 0.025.

Key concepts

Equivalents

When diving into chemistry, you might come across the term "equivalents." This concept is fundamental in calculating the concentration of solutions, especially when dealing with reactions that aren't simply 1:1. An equivalent represents the amount of a substance that will react with or supply a particular amount of another substance. It reflects the reactive capacity of a molecule based on the number of moles contributing to the reaction. For example, sulfuric acid (\(\mathrm{H}_{2}\mathrm{SO}_{4}\)) disassociates into two hydrogen ions (\(\mathrm{H}^{+}\)), which means it has two equivalents per mole. This concept helps in determining how much of a compound will readily participate in a given chemical reaction, compared to the mere presence of a substance.

Milliequivalents

Milliequivalents (meq) serve as a smaller unit for equivalents to make calculations more manageable, especially when dealing with small quantities of substances. Just as there are 1,000 milligrams in a gram, there are 1,000 milliequivalents in one equivalent, which can be helpful in contexts where substances are in low concentrations. For instance, if you have 50 milliequivalents of \(\mathrm{H}_{2}\mathrm{SO}_{4}\), this equates to \(50 / 1000 = 0.05\) equivalents of the substance. Being comfortable converting between milliequivalents and equivalents can aid in achieving accurate results for scientific calculations.

Concentration calculation

Concentration often refers to how much solute is present in a solution and can be expressed in various terms such as molarity, molality, and normality, each serving different purposes. For normality, it's specific to the reactive capacity where the formula is: \[\text{Normality (N)} = \frac{\text{Equivalents}}{\text{Volume of solution in L}}\]This means that you divide the number of equivalents by the volume of the solution in liters. In our original problem, we had 0.05 equivalents of \(\mathrm{H}_{2}\mathrm{SO}_{4}\) in a 2-liter solution. Therefore, applying the normality formula, we calculate: \[\text{Normality (N)} = \frac{0.05}{2} = 0.025 \text{ N}\]This mathematical approach provides the concentration of the solution in terms of normality, making it easier to understand the relationship between the solute and solution in chemical reactions.