To calculate the amount of NaCl required to render 100ml of a 1% solution of apomorphine HCl isotonic with blood serum, we first need to understand what isotonicity means in this context.

Isotonicity refers to a solution having the same osmotic pressure as another solution. In the case of blood serum, it has an osmotic pressure of about 0.9% NaCl.

Given that you have a 1% solution of apomorphine HCl, you want to adjust it to be isotonic with blood serum. To do this, you'll need to calculate the additional NaCl required.

First, let's find out how much NaCl is already present in the 1% solution of apomorphine HCl:

1% solution means 1g of apomorphine HCl in 100ml of solution.

Next, we need to calculate the osmotic pressure contributed by the apomorphine HCl:

The molecular weight of apomorphine HCl is about 303.7 g/mol.

So, 1g of apomorphine HCl is approximately 0.0033 moles (1g / 303.7 g/mol).

Now, to calculate the osmotic pressure contributed by apomorphine HCl, we use the formula:

Osmotic pressure = (number of moles of solute) × (ideal gas constant) × (temperature in Kelvin) × (volume of solution in liters)

The temperature for physiological solutions is usually taken as 37°C, which is 310 Kelvin.

So, the osmotic pressure contributed by apomorphine HCl is approximately:

Osmotic pressure = 0.0033 moles × 0.0821 atm L/mol K × 310 K / 0.1 L = 0.084 atm

To make the solution isotonic with blood serum (0.9% NaCl), you need to adjust the osmotic pressure by adding NaCl.

The osmotic pressure contributed by 0.9% NaCl is approximately:

0.9% NaCl = 0.9g NaCl / 58.44 g/mol (molecular weight of NaCl) = 0.0154 moles

So, the osmotic pressure contributed by 0.9% NaCl is:

Osmotic pressure = 0.0154 moles × 0.0821 atm L/mol K × 310 K / 0.1 L = 0.397 atm

The difference in osmotic pressure required to make the solution isotonic with blood serum is:

0.397 atm - 0.084 atm = 0.313 atm

Now, we need to find out how much NaCl is needed to produce an additional osmotic pressure of 0.313 atm.

Using the formula for osmotic pressure:

0.313 atm = (number of moles of NaCl) × 0.0821 atm L/mol K × 310 K / 0.1 L

Solving for the number of moles of NaCl:

Number of moles of NaCl = 0.313 atm × 0.1 L / (0.0821 atm L/mol K × 310 K) ≈ 0.004 moles

Finally, convert moles of NaCl to grams:

0.004 moles × 58.44 g/mol = 0.234 g

So, approximately 0.234 grams of NaCl is required to render 100ml of a 1% solution of apomorphine HCl isotonic with blood serum.