Question 1

Which of the following best describes the main purpose of mixing in pharmaceutical technology?

Accepted Answer

To achieve uniformity of composition and promote physical or chemical reactions

Question 2

Which physical property is LEAST likely to affect the ease of mixing solids in tablet manufacturing?

Accepted Answer

Color of the particles

Question 3

A pharmaceutical company is experiencing poor mixing in their production line. Which of the following is NOT a likely reason for this issue?

Accepted Answer

Accurate understanding of mixing objectives

Question 4

Which type of mixer operates on the principle of bulk transport and shear, and is commonly used for mixing solids?

Accepted Answer

Tumble mixer

Question 5

In a ribbon blender, what is the primary function of the helical ribbons?

Accepted Answer

To move material axially in opposite directions and radially

Question 6

Which mechanism of mixing is characterized by the deliberate bulk movement of packets of powder around the powder mass?

Accepted Answer

Convective mixing

Question 7

A pharmaceutical batch requires gentle mixing to avoid damaging delicate ingredients. Which mixer is most suitable?

Accepted Answer

Vertical blender with slow turning auger

Question 8

Which of the following is a disadvantage of the tumbler mixer?

Accepted Answer

Segregation occurs with mixtures having wide particle size distribution

Question 9

Which type of mixture is represented by a statistical variation in composition among samples withdrawn at any time from a mix?

Accepted Answer

Random mixture

Question 10

A pharmaceutical engineer wants to quantify the degree of mixing in a batch of solid particles. Which statistical measure should be used?

Accepted Answer

Standard deviation $$S or $$variance $$s^2$$

Question 11

Which of the following statements about agitation and mixing is TRUE?

Accepted Answer

Agitation usually creates a circulatory pattern inside a container

Question 12

Which impeller type is most likely to generate currents parallel with the axis of the impeller shaft?

Accepted Answer

Axial-flow impeller

Question 13

A pharmaceutical process requires dispersing a second liquid, immiscible with the first, to form an emulsion. Which operation is most relevant?

Accepted Answer

Dispersing a second liquid to form an emulsion or suspension of fine drops

Question 14

Which of the following is NOT an advantage of the ribbon blender?

Accepted Answer

High heat development for sensitive ingredients

Question 15

A pharmaceutical company is scaling up production and needs to select a mixer. Which factor is LEAST important in logical mixer selection?

Accepted Answer

Color of the mixer

Question 16

Which of the following statements about mixing efficiency in tumble blenders is correct?

Accepted Answer

Mixing efficiency has a direct correlation with the speed of rotation

Question 17

Which mixer is most appropriate for adding small amounts of liquid to coat or absorb coloring, flavoring, or oils onto solids?

Accepted Answer

Ribbon blender with spray nozzles

Question 18

Which of the following statements about power consumption and mixing is TRUE?

Accepted Answer

Propellers typically require longer mixing times compared to turbines

Question 19

A pharmaceutical engineer observes swirling stratification at various levels in a mixing tank, with no longitudinal flow between levels. What is the most likely cause?

Accepted Answer

Incorrect impeller type or tank design

Question 20

Which equation would you use to quantify the degree of mixing in a batch of solid particles?

Accepted Answer

$$s^2$$ = \frac{1}{N} \sum_{i=1}^{N} (x_i - \bar{x}$$)^2$$

Pharmaceutical Mixing: Principles, Equipment, and Mechanisms

Study Guide - Practice Questions

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