11. Consider the following properties of minerals:
- Colour
- Density
- Hardness
- Chemical property
Which of the above properties are used to determine the type of minerals?
[A] Only 1, 2 and 3
[B] All of the above
[C] Only 2, 3 and 4
[D] Only 1, 2 and 4
Show Answer
Correct Answer: B [All of the above]
Notes:
The type of minerals is determined by various physical and chemical properties, including colour, density, hardness, and chemical properties like solubility. All these characteristics are essential for mineral identification, making all the given options correct in determining mineral types.
12. Consider the following statements:
- It is a major constituent of biological membranes, nucleic acids, and cellular energy transfer systems.
- It is needed to make shells, bones, and teeth.
Which of the following elements has been described in the above statements?
[A] Carbon
[B] Phosphorus
[C] Nitrogen
[D] Sulphur
Show Answer
Correct Answer: B [Phosphorus]
Notes:
Phosphorus plays a crucial role in biological membranes (phospholipids), is a component of nucleic acids (DNA, RNA), and is involved in cellular energy transfer (ATP, ADP). Additionally, it is essential for the formation of bones, teeth, and shells in various animals, distinguishing it from the other listed elements.
13. Which of the following pairs are correctly matched regarding the uses of acids?
- Hydrochloric acid – Extracting glue from bones
- Nitric acid – Refining gold and silver
- Sulphuric acid – Textile industry
Select the correct answer from the codes given below:
[A] Only 1 and 2
[B] Only 2 and 3
[C] Only 1 and 3
[D] 1, 2 & 3
Show Answer
Correct Answer: A [Only 1 and 2]
Notes:
Hydrochloric acid is used in extracting glue from bones. Nitric acid is used in refining gold and silver. Sulphuric acid is mainly used in manufacturing fertilizers, detergents, plastics, and in petroleum refining, but not primarily in the textile industry. Thus, only statements 1 and 2 are correctly matched.
14. Which of the following is/are correct for mixtures?
- Mixtures are constituted by more than one kind of pure form of matter.
- Alloys are mixtures of two or more metals or a metal and a non-metal and cannot be separated into their components by physical methods.
Select the correct answer from the codes given below:
[A] Only 1
[B] Only 2
[C] Both 1 and 2
[D] None of the above
Show Answer
Correct Answer: C [Both 1 and 2]
Notes:
Mixtures are constituted by more than one kind of pure form of matter. Alloys are mixtures of two or more metals or a metal and a non-metal and cannot be separated into their components by physical methods. But still, an alloy is considered as a mixture because it shows the properties of its constituents and can have variable composition. For example, brass is a mixture of approximately 30% zinc and 70% copper.
15. Which of the following statements regarding compounds is/are correct?
- It is a substance composed of two or more elements.
- The composition of each new substance is always fixed.
- It shows the properties of the constituent substances.
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: A [Only 1 & 2]
Notes:
Compounds are substances formed from two or more elements combined in a fixed ratio by mass. The properties of a compound are different from those of its constituent elements. Compounds have a definite composition that can be separated only by chemical or electrochemical means. Thus, statements 1 and 2 are correct, while statement 3 is incorrect.
16. Which of the following statements regarding Dalton’s atomic theory are correct:
- All matter is made up of very tiny particles called atoms.
- Atoms do not participate in chemical reactions.
- Atoms are indivisible particles.
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: C [Only 1 & 3]
Notes:
Dalton’s atomic theory states that all matter consists of tiny particles called atoms, and that atoms are indivisible particles. However, it also says that atoms participate in chemical reactions; hence, statement 2 is incorrect. Statements 1 and 3 are correct according to Dalton’s postulates.
17. Which of the following pairs are correctly matched?
- Mercury – liquid at room temperature
- Iodine – non-lustrous
- Lithium – low melting point
- Graphite – good conductor
Select the correct answer using the codes given below:
[A] Only 1, 2 & 3
[B] Only 1, 2 & 4
[C] Only 1, 3 & 4
[D] Only 2, 3 & 4
Show Answer
Correct Answer: C [Only 1, 3 & 4]
Notes:
Mercury is the only metal liquid at room temperature. Iodine, though a non-metal, is lustrous, so the match is incorrect. Lithium is an alkali metal with a low melting point. Graphite, an allotrope of carbon, is a good conductor of electricity. Thus, only statements 1, 3, and 4 are correct.
18. Which of the following is correct for a physical change?
- Only physical properties change.
- Large amount of heat is absorbed or evolved.
Select the correct answer from the codes given below:
[A] Only 1
[B] Only 2
[C] Both 1 and 2
[D] None of the above
Show Answer
Correct Answer: A [Only 1]
Notes:
Properties such as shape, size, colour and state of a substance are called its physical properties. A change in which a substance undergoes a change in its physical properties is called a physical change. A physical change is generally reversible. In such a change no new substance is formed. Physical changes are temporary and reversible. No or very small amount of energy is either absorbed or evolved during a physical change.
19. Which of the following are correctly matched :
- Coke- pure form of carbon.
- Coal tar- black, thin liquid.
- Coal gas- manufacturing perfumes.
Select the correct answer from the codes given below:
[A] All are correct
[B] Only 1 and 2
[C] Only 2 and 3
[D] Only 1 and 3
Show Answer
Correct Answer: B [Only 1 and 2]
Notes:
- Coke – pure form of carbon: This match is correct. Coke is a high-carbon-content material that is derived from coal and is primarily composed of pure carbon.
- Coal tar – black, thin liquid: This match is also correct. Coal tar is a thick, black, and sticky liquid byproduct obtained during the destructive distillation of coal. It is commonly used in various industrial applications.
- Coal gas – manufacturing perfumes: This match is incorrect. Coal gas is a flammable gas produced by the incomplete combustion of coal. It has been historically used for lighting and heating purposes but is not used in the manufacturing of perfumes.
20. Which of the following are correctly matched?
- Dispersed phase- dispersed particles
- Dispersion medium- dispersed phase is suspended
- Aerosol- fog
Select the correct answer from the codes given below:
[A] Only 1 and 2
[B] Only 2 and 3
[C] Only 1 and 3
[D] All of the above
Show Answer
Correct Answer: D [All of the above ]
Notes:
The components of a colloidal solution are the dispersed phase and the dispersion medium. The solute-like component or the dispersed particles in a colloid form the dispersed phase, and the component in which the dispersed phase is suspended is known as the dispersing medium. Examples of Aerosol: fog, clouds, mist.
