# DBT JRF 2022 — Question 48

Exam: DBT JRF 2022 · Section: A · Topic: Biochemistry › Biomolecule Structure Identification · Difficulty: Medium

## Question

What is the molecular formula for the structure given below? ![figure](https://res.cloudinary.com/dxil5euku/image/upload/v1779453120/pyq/6a104cb5920734408bc0c6d8/DBTJRF22-IMGA48.png)

## Options

- **A.** $C_{12}H_{17}ClN_4OS$
- **B.** $C_{10}H_{16}ClN_4OS$
- **C.** $C_{11}H_{16}ClN_4OS$
- **D.** $C_{13}H_{16}ClN_4OS$

## Answer

Option A

## Explanation

Identifying the molecular structure ![figure](https://res.cloudinary.com/dxil5euku/image/upload/v1779453120/pyq/6a104cb5920734408bc0c6d8/DBTJRF22-IMGA48.png) : The structure shown in the image is Thiamine (Vitamin B1), which consists of: • A pyrimidine ring (containing 2 nitrogen atoms and carbon/hydrogen substituents) • A thiazole ring (containing 1 sulfur and 1 nitrogen) • Connected by a methylene bridge • A chloride counterion (from HCl salt form) Molecular formula: $\text{C}_{12}\text{H}_{17}\text{ClN}_4\text{OS}$ Atom count: 12 C, 17 H, 1 Cl, 4 N (2 from pyrimidine + 1 from thiazole + 1 from amino group), 1 O, 1 S Answer: $\text{C}_{12}\text{H}_{17}\text{ClN}_4\text{OS}$ (Option 1).

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