20ml Hcl whose treated with excess of AgNo3 the ppt was formed with constant weight 0.3589 * find the normality and stranse of Hcl

To determine the normality and strength of the hydrochloric acid (HCl) solution based on the reaction with silver nitrate (AgNO3), we need to follow a series of logical steps. The formation of a precipitate indicates that a reaction has occurred, specifically the formation of silver chloride (AgCl) when AgNO3 reacts with HCl. Let's break this down step by step.

Understanding the Reaction

The balanced chemical equation for the reaction between HCl and AgNO3 is:

AgNO3 + HCl → AgCl (s) + HNO3

From this equation, we can see that one mole of HCl reacts with one mole of AgNO3 to produce one mole of AgCl. This stoichiometry is crucial for our calculations.

Calculating Moles of AgCl

First, we need to determine how many moles of AgCl were formed. The weight of the precipitate (AgCl) is given as 0.3589 grams. To find the number of moles, we use the molar mass of AgCl:

• Molar mass of Ag = 107.87 g/mol
• Molar mass of Cl = 35.45 g/mol
• Molar mass of AgCl = 107.87 + 35.45 = 143.32 g/mol

Now, we can calculate the moles of AgCl:

Moles of AgCl = mass / molar mass = 0.3589 g / 143.32 g/mol ≈ 0.0025 moles

Relating Moles of AgCl to HCl

Since the reaction shows a 1:1 molar ratio between HCl and AgCl, the moles of HCl that reacted will also be 0.0025 moles.

Finding Normality of HCl

Normality (N) is defined as the number of equivalents of solute per liter of solution. For HCl, which is a strong acid, one mole of HCl provides one equivalent of H⁺. Therefore, the normality is equal to the molarity for HCl.

To find the normality, we need to know the volume of the HCl solution used, which is 20 mL or 0.020 L:

Normality (N) = equivalents / volume (L) = moles of HCl / volume (L)

N = 0.0025 moles / 0.020 L = 0.125 N

Calculating Strength of HCl

The strength of an acid solution is often expressed in terms of grams of solute per liter of solution. To find the strength of HCl, we can use the molarity we just calculated:

Since we have 0.0025 moles of HCl in 0.020 L, we can find the mass of HCl:

• Molar mass of HCl = 1.01 (H) + 35.45 (Cl) = 36.46 g/mol

Mass of HCl = moles × molar mass = 0.0025 moles × 36.46 g/mol ≈ 0.09115 g

To find the strength in grams per liter, we scale this up to 1 L:

Strength = (0.09115 g / 0.020 L) × 1 L = 4.5575 g/L

Summary of Results

In summary, the normality of the HCl solution is approximately 0.125 N, and the strength of the HCl solution is about 4.56 g/L. This methodical approach allows us to derive important properties of the acid solution based on the reaction with silver nitrate.