Determine the volume of a 0.1 M solution of HCl, necessary to titrate 20 mL of a 0.5 M solution of NH3. The value of Kb is 1.8 x 10-5.

To determine the volume of the HCl solution necessary to titrate the NH3 solution, we first need to write and balance the chemical equation for the reaction between HCl and NH3.

The balanced equation for the reaction is:
NH3 + HCl -> NH4Cl

From the balanced equation, we can see that 1 mole of NH3 reacts with 1 mole of HCl to form 1 mole of NH4Cl.

Given:
- Volume of NH3 solution = 20 mL = 0.02 L
- Concentration of NH3 solution = 0.5 M
- Concentration of HCl solution = 0.1 M
- Kb (ionization constant of NH3) = 1.8 x 10^-5

We need to determine the volume of HCl solution required to react completely with the NH3 solution.

Step 1: Calculate the moles of NH3
Moles of NH3 = concentration * volume
Moles of NH3 = 0.5 M * 0.02 L
Moles of NH3 = 0.01 moles

Step 2: Since the balanced equation shows that 1 mole of NH3 reacts with 1 mole of HCl, we can say that the moles of NH3 equals the moles of HCl required to react completely.

Moles of HCl = 0.01 moles

Step 3: Calculate the volume of HCl solution
Volume of HCl solution = Moles of HCl / Concentration
Volume of HCl solution = 0.01 moles / 0.1 M
Volume of HCl solution = 0.1 L = 100 mL

Therefore, the volume of the 0.1 M HCl solution necessary to titrate 20 mL of the 0.5 M NH3 solution is 100 mL.

To determine the volume of the 0.1 M HCl solution required to titrate 20 mL of the 0.5 M NH3 solution, we first need to calculate the number of moles of NH3 in the 20 mL solution.

Step 1: Calculate moles of NH3
Moles of NH3 = (Concentration of NH3) x (Volume of NH3 solution)
= (0.5 M) x (20 mL)
= 0.5 moles

Step 2: Calculate moles of HCl required for titration
According to the balanced chemical equation for the reaction between NH3 and HCl:
NH3 + HCl → NH4Cl
The stoichiometric ratio between NH3 and HCl is 1:1. Therefore, the moles of HCl required to neutralize the NH3 is also 0.5 moles.

Step 3: Calculate volume of 0.1 M HCl solution
To find the volume of the 0.1 M HCl solution needed, we can use the equation:

Moles of HCl = (Concentration of HCl) x (Volume of HCl solution)

We rearrange the equation to solve for the volume of the HCl solution:

Volume of HCl solution = Moles of HCl / Concentration of HCl

Plugging in the values:

Volume of HCl solution = 0.5 moles / 0.1 M
= 5 mL

Therefore, you would need 5 mL of a 0.1 M solution of HCl to titrate 20 mL of a 0.5 M solution of NH3.

20 mL NH3 x 0.5 M NH3 = mL HCl x 0.1 M HCl. Solve for mL HCl.