Assertion : Pairing and separation of pair of chromosomes would lead to segregation of a pair of factors they carried
Reason : Two alleles of a gene pair are located on similar sites on non-homologous chromosomes

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that "Pairing and separation of a pair of chromosomes would lead to the segregation of a pair of factors they carried." This refers to the process of meiosis where homologous chromosomes pair up and then separate, leading to the segregation of alleles (factors) they carry.

2. **Explaining Chromosomal Theory of Inheritance:**
- According to the chromosomal theory of inheritance, chromosomes are the carriers of genes (Mendelian factors). During meiosis, these chromosomes segregate independently, which aligns with Mendel's law of segregation.

3. **Evaluating the Reason:**
- The reason given is "Two alleles of a gene pair are located on similar sites on non-homologous chromosomes." This statement is incorrect. In reality, alleles of a gene pair are located at the same locus (position) on homologous chromosomes, not on non-homologous chromosomes.

4. **Conclusion:**
- Since the assertion is true (it correctly describes the segregation of chromosomes during meiosis) and the reason is false (it incorrectly describes the location of alleles), we conclude that the assertion is true while the reason is false.

**Final Answer:**
- The assertion is true, but the reason is false.

---