What is the chemical name of vitamin `B_(1)` and which disease is caused by its deficiency?

Explanation

### Step-by-Step Solution:

1. **Identify the Vitamin**: The question asks for the chemical name of vitamin B1.
- Vitamin B1 is commonly known as thiamine.

2. **Understand the Deficiency**: Next, we need to determine the disease caused by the deficiency of vitamin B1.
- The deficiency of vitamin B1 (thiamine) leads to a disease known as beriberi.

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