Which of the following property does not describe a compound?
Which of the following property does not describe a compound?
The correct option is D (d) It is mixed in any proportion by mass.
Explanation for correct option:
(D) It is mixed in any proportion by mass.
Compounds are always mixed in a fixed proportion by mass.
- A molecule of ammonia with the formula indicates that the three hydrogen atoms are bonded to one nitrogen atom with a fixed ratio of 3:1 respectively.
- A molecule of methane with the formula indicates that the four hydrogen atoms are bonded to one carbon atom with a fixed ratio of 4:1 respectively.
Therefore, option (d) is not a characteristic of the compound.
Explanation for incorrect options:
(A) It is composed of two or more elements
A compound is formed when two or more elements are combined chemically with one another in a fixed proportion.
- A water molecule with the formula indicates that the two hydrogen atoms are bonded to one oxygen atom with a fixed ratio of 2:1 respectively. So a water molecule is a compound with two different elements hydrogen and oxygen.
- A sugar molecule with the formula is composed of 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms. So a compound can be of two or more elements.
(B) It is a pure substance
A compound is composed of only one type of molecule. Molecules are composed of two or more types of atoms. This makes the compound a pure substance.
(C) It cannot be separated into constituents by physical means
As the elements are chemically combined to form compounds, separating them by the physical method is impossible. Its constituents can only be separated by chemical or electrochemical methods.
Therefore, options (A), (B), and (C) are the characteristics of the compound.
Hence, option (D) is correct. The compound is not mixed in any proportion by mass.
(d) It is mixed in any proportion by mass.
Explanation for correct option:
(D) It is mixed in any proportion by mass.
Compounds are always mixed in a fixed proportion by mass.
- A molecule of ammonia with the formula indicates that the three hydrogen atoms are bonded to one nitrogen atom with a fixed ratio of 3:1 respectively.
- A molecule of methane with the formula indicates that the four hydrogen atoms are bonded to one carbon atom with a fixed ratio of 4:1 respectively.
Therefore, option (d) is not a characteristic of the compound.
Explanation for incorrect options:
(A) It is composed of two or more elements
A compound is formed when two or more elements are combined chemically with one another in a fixed proportion.
- A water molecule with the formula indicates that the two hydrogen atoms are bonded to one oxygen atom with a fixed ratio of 2:1 respectively. So a water molecule is a compound with two different elements hydrogen and oxygen.
- A sugar molecule with the formula is composed of 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms. So a compound can be of two or more elements.
(B) It is a pure substance
A compound is composed of only one type of molecule. Molecules are composed of two or more types of atoms. This makes the compound a pure substance.
(C) It cannot be separated into constituents by physical means
As the elements are chemically combined to form compounds, separating them by the physical method is impossible. Its constituents can only be separated by chemical or electrochemical methods.
Therefore, options (A), (B), and (C) are the characteristics of the compound.
Hence, option (D) is correct. The compound is not mixed in any proportion by mass.
