## How many ml of Glycerin would be needed to prepare 1 lb of an ointment containing i5% W/W Glycerin? (The density of glycerin is 1.25g/ml):

**a-**1.2ml**b-**18.2ml*****c-**22.7ml**d-**24ml**e-**28.4ml.

### The answer is 18.2ml.

To prepare 1 lb of an ointment containing 15% W/W Glycerin, we would need 15 grams of Glycerin. The density of Glycerin is 1.25g/ml, so this would correspond to 15/1.25 = 12ml of Glycerin.

However, the question asks for the volume of Glycerin needed to prepare 1 lb of an ointment, not the weight. Since the ointment will also contain other ingredients, the total volume of the ointment will be greater than 12ml.

#### To calculate the volume of Glycerin needed, we can use the following equation:

- Volume of Glycerin = (Weight of Glycerin) / (Density of Glycerin)
- Volume of Glycerin = (15 grams) / (1.25g/ml)
- Volume of Glycerin = 12ml

Therefore, we would need 12ml of Glycerin to prepare 1 lb of an ointment containing 15% W/W Glycerin.

However, the question asks for the volume of Glycerin needed to prepare 1 lb of an ointment, not the weight. Since the ointment will also contain other ingredients, the total volume of the ointment will be greater than 12ml.

#### To calculate the total volume of the ointment, we can use the following equation:

- Total volume of ointment = (Volume of Glycerin) / (Percentage of Glycerin)
- Total volume of ointment = (12ml) / (15%)
- Total volume of ointment = 80ml

Therefore, we would need 12ml of Glycerin to prepare 1 lb of an ointment containing 15% W/W Glycerin.

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