KAPS Pharmaceutical Chemistry and Analysis 4

Question 1

A drug with a pKa of 4.5 is administered orally. In the stomach (pH 1.5), the drug exists predominantly as:

Accepted Answer

Ionized (acid form)

Answer

Unionized (base form)

Answer

Zwitterion

Answer

Equally ionized and unionized

Question 2

Which analytical technique provides both molecular weight and structural fragmentation information simultaneously?

Accepted Answer

Mass spectrometry

Answer

NMR spectroscopy

Answer

IR spectroscopy

Answer

UV spectroscopy

Question 3

The Maillard reaction in pharmaceutical formulations occurs between:

Accepted Answer

Primary amines and reducing sugars

Answer

Lipids and oxygen

Answer

Alcohols and carboxylic acids

Answer

Phenols and peroxides

Question 4

In titrimetry, what is the primary purpose of a primary standard?

Accepted Answer

To standardize the concentration of the titrant solution accurately

Answer

To adjust the pH of the titrant

Answer

To indicate the endpoint visually

Answer

To buffer the analyte solution

Question 5

Which phenomenon describes the ability of a drug molecule to exist in multiple crystalline forms with different physicochemical properties?

Accepted Answer

Polymorphism

Answer

Isomerism

Answer

Racemization

Answer

Tautomerism

Question 6

Which functional group is responsible for the characteristic absorption around 1710 cm⁻¹ in an IR spectrum?

Accepted Answer

C=O stretch of carbonyls

Answer

O-H stretch of alcohols

Answer

N-H bend of amines

Answer

C-H stretch of alkanes

Question 7

Accelerated stability testing of pharmaceuticals is conducted at elevated temperatures and humidity primarily to:

Accepted Answer

Predict shelf-life using the Arrhenius equation

Answer

Determine the drug's melting point

Answer

Identify polymorphic transitions only

Answer

Measure optical rotation changes