(d) If 45.3 mL of a 0.108 M HCl solution is needed to neutralize a solution of KOH, how many grams of KOH must be present in the solution?

Verified step by step guidance

1. Step 1: First, we need to calculate the moles of HCl used in the reaction. We can do this by multiplying the volume of the HCl solution (in liters) by its molarity. The molarity of a solution is defined as the number of moles of solute per liter of solution. So, the moles of HCl can be calculated using the formula: moles = volume (L) * molarity (M).
2. Step 2: In the neutralization reaction between HCl and KOH, the stoichiometry is 1:1. This means that one mole of HCl reacts with one mole of KOH. Therefore, the moles of KOH in the solution will be equal to the moles of HCl calculated in step 1.
3. Step 3: Now, we need to convert the moles of KOH to grams. We can do this by multiplying the moles of KOH by the molar mass of KOH. The molar mass of KOH (K=39.10 g/mol, O=16.00 g/mol, H=1.01 g/mol) is approximately 56.11 g/mol. So, the mass of KOH can be calculated using the formula: mass (g) = moles * molar mass (g/mol).
4. Step 4: The result from step 3 will give you the mass of KOH in grams that must be present in the solution to neutralize the given volume and molarity of HCl.

Key Concepts

Acid-Base Neutralization

Acid-base neutralization is a chemical reaction where an acid reacts with a base to produce water and a salt. In this case, hydrochloric acid (HCl) reacts with potassium hydroxide (KOH). The reaction can be represented as HCl + KOH → KCl + H2O, illustrating how the acidic and basic properties cancel each other out.

Molarity and Volume Relationship

Molarity (M) is a measure of concentration defined as moles of solute per liter of solution. To find the number of moles of HCl in the given volume, you can use the formula: moles = molarity × volume (in liters). This relationship is crucial for determining how much KOH is needed for neutralization based on the stoichiometry of the reaction.

Stoichiometry

Stoichiometry involves the calculation of reactants and products in chemical reactions based on balanced equations. For the neutralization of HCl and KOH, the stoichiometric coefficients indicate a 1:1 ratio, meaning one mole of HCl reacts with one mole of KOH. This concept is essential for converting moles of HCl to moles of KOH and subsequently to grams using the molar mass of KOH.