Question

Which of the following statements are true for pure substances?

(i) Pure substances contain only one kind of particle.

(ii) Pure substances may be compounds or mixtures.

(iii) Pure substances have the same composition throughout.

(iv) Pure substances can be exemplified by all elements other than nickel.

• A. (i) and (ii)
• B. (i) and (iii)
• C. (iii) and (iv)
• D. (ii) and (iii)

Answer 1

The correct option is B

(i) and (iii)

Explanation for the correct options:

(B) (i) and (iii)

• (i) Pure substances contain only one kind of particle - Atoms, molecules, elements, or compounds are the only types of particles that make up a pure substance.
• (iii)Pure substances have the same composition throughout - Being homologous means that a pure substance has a consistent makeup throughout.

Explanation for the incorrect options:

(A) (ii)Pure substances may be compounds or mixtures-

• Elements or compounds are created from pure substances.

(C) (iv)Pure substances can be exemplified by all elements other than nickel-

• All elements besides nickel cannot serve as examples of pure substances since pure nickel is an element with only one type of particle.

(D) (ii)Pure substances may be compounds or mixtures-

• Elements or compounds are created from pure substances.

Hence, option (B) is correct, pure substances contain only one kind of particle and pure substances may be compounds or mixtures are true for pure substances.