Which of the the following statements are true for pure substance ?
(i) pure substance contain only one kind of particles
(ii) pure substance may be compounds or mixtures
(ii) pure substance have the same composition throughout
(iv) pure substances can be exemplified by all elements other than nickel

Options

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

Answer

To determine which statements are true for pure substances, let's analyze each statement step by step.

### Step-by-Step Solution:

1. **Statement (i): Pure substance contains only one kind of particles.**
- **Analysis**: A pure substance is defined as a material that has a uniform and definite composition. This means it consists of only one type of particle, which can be either atoms (in the case of elements) or molecules (in the case of compounds).
- **Conclusion**: This statement is **True**.

2. **Statement (ii): Pure substance may be compounds or mixtures.**
- **Analysis**: Pure substances can either be elements or compounds. Mixtures, by definition, contain two or more different types of particles and do not have a uniform composition. Therefore, mixtures cannot be classified as pure substances.
- **Conclusion**: This statement is **False**.

3. **Statement (iii): Pure substances have the same composition throughout.**
- **Analysis**: By definition, pure substances have a consistent and uniform composition. This means that no matter where you take a sample from a pure substance, it will have the same properties and composition.
- **Conclusion**: This statement is **True**.

4. **Statement (iv): Pure substances can be exemplified by all elements other than nickel.**
- **Analysis**: Pure substances include all elements, including nickel. There is no restriction on which elements can be considered pure substances. Therefore, this statement incorrectly excludes nickel.
- **Conclusion**: This statement is **False**.

### Summary of Results:
- Statement (i): True
- Statement (ii): False
- Statement (iii): True
- Statement (iv): False

### Final Answer:
The true statements for pure substances are:
- (i) and (iii) are true.

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