Q661. Which of the following chemicals is commonly used as a commercial food preservative for fruit juices and jams?
RAS Prelims MCQ Practice
9,654 RAS Prelims practice MCQs with the correct answer and a clear explanation for each. Filter by subject and chapter.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
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Q662. Saccharin and aspartame are primarily used in the food industry as:
Explanation
Saccharin and aspartame are popular artificial sweetening agents used as low-calorie alternatives to sucrose, or common table sugar. They are many times sweeter than natural sugar, meaning only tiny amounts are required to achieve the desired level of sweetness. These compounds are particularly useful for individuals with diabetes or those looking to reduce their caloric intake without sacrificing sweet taste in foods.
Q663. Monosodium glutamate (MSG) is added to packaged foods primarily to:
Explanation
Monosodium glutamate, commonly referred to as MSG, is a sodium salt derived from the amino acid glutamic acid. It is added to various packaged and processed foods primarily to enhance their savory, meaty flavor, often described as "umami." While it occurs naturally in some foods like tomatoes and cheeses, its concentrated form is used by the food industry to intensify the taste.
Q664. Chemicals applied to living tissues to kill or prevent the growth of microbes are called:
Explanation
Antiseptics are chemical substances specifically designed to be applied to living tissues, such as skin or wounds, to kill or inhibit the growth of microorganisms. Unlike disinfectants, which are stronger and used on inanimate objects like floors, antiseptics must be safe enough to prevent infection without causing significant damage to the host’s cells. Common examples include iodine and alcohol solutions.
Q665. Toothpastes are generally formulated to be slightly basic in nature. What is the primary chemical reason for this?
Explanation
Bacteria in the mouth ferment food particles, particularly sugars, to produce organic acids that can erode tooth enamel and lead to cavities. Toothpastes are formulated to be slightly basic to effectively neutralize these harmful acids. This neutralizing action helps to maintain a healthy pH balance in the oral cavity, protecting the calcium phosphate structure of the teeth and promoting overall dental health.
Q666. Consider the following common agricultural fertilizers:
I. Urea
II. Superphosphate
III. Potassium chloride (Muriate of potash)
IV. Sodium chloride
Which of the above identify primary NPK (Nitrogen, Phosphorus, Potassium) fertilizers?
I. Urea
II. Superphosphate
III. Potassium chloride (Muriate of potash)
IV. Sodium chloride
Which of the above identify primary NPK (Nitrogen, Phosphorus, Potassium) fertilizers?
Explanation
NPK fertilizers are those that provide one or more of the three primary macronutrients essential for plant growth: nitrogen, phosphorus, and potassium. Urea is a major source of nitrogen, superphosphate provides phosphorus, and potassium chloride, also known as muriate of potash, provides potassium. Sodium chloride, or common salt, is not used as a fertilizer as it does not provide these nutrients.
Q667. DDT (Dichloro-diphenyl-trichloroethane) was widely used globally as an:
Explanation
DDT is a potent synthetic organochlorine compound that was once widely used globally as an insecticide in both agriculture and disease control. It was particularly effective in reducing the populations of mosquitoes that carry malaria and lice that spread typhus. However, its long-term environmental persistence and harmful effects on wildlife led to widespread bans or severe restrictions on its use globally.
Q668. Most commercial liquid drain cleaners are highly caustic and rely on which strong base to dissolve clogs?
Explanation
Most commercial liquid drain cleaners contain a high concentration of sodium hydroxide, also known as caustic soda or lye. This strong base is highly effective at dissolving organic clogs, such as hair, grease, and food particles, through a process of chemical decomposition. Its caustic nature allows it to break down tough blockages quickly, though it must be handled with extreme care.
Q669. The mechanical advantage of a simple machine is defined as the ratio of:
Explanation
The mechanical advantage of a simple machine is a measure of its force-amplifying ability. It is mathematically defined as the ratio of the output force, or load, to the input force, or effort. A mechanical advantage greater than one indicates that the machine allows a user to move a heavy load with relatively less effort, making physical tasks much easier to perform.
Q670. A pair of scissors is an example of a:
Explanation
A pair of scissors is a classic example of a Class 1 lever. In this arrangement, the fulcrum or pivot point is located between the effort applied by the fingers at the handles and the load, which is the material being cut by the blades. This configuration allows for a change in the direction of force and can be designed to provide a mechanical advantage.Answer key for these questions
| Q | Correct answer |
|---|---|
| 661 | (d) Sodium benzoate |
| 662 | (a) Artificial sweetening agents |
| 663 | (c) Enhance flavor |
| 664 | (a) Antiseptics |
| 665 | (d) To neutralize the acids produced by bacteria in the mouth |
| 666 | (a) I, II and III only |
| 667 | (c) Insecticide |
| 668 | (d) Sodium hydroxide |
| 669 | (a) Load force to effort force |
| 670 | (b) Class 1 lever |
Frequently asked questions
How many RAS Prelims practice MCQs are there on RAS Prelims?
This page has 9654 practice MCQs on the RAS Prelims syllabus. Each has the correct answer, and most have an explanation.
How should I practise MCQs for RAS Prelims?
Attempt each question first, then open the answer and read the explanation. Practise one chapter at a time, note the facts you got wrong and revise them. Repeat the chapter after a few days.
Are these actual RAS Prelims past-paper questions?
No. These are practice questions written for the RAS Prelims syllabus. They follow the pattern the exam uses: factual questions, statement-based questions, match-the-list and assertion-reason.