GATE 2022 BT – Question 29
The degree of reduction of lactic acid (C3H6O3) is ________________.
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Correct answer: 4 to 4
Explanation
The **degree of reduction** $\gamma$ of a compound is the number of electrons available per carbon atom (per C-mole), taking C = 4, H = 1, O = −2 and N = −3 as the contributions of each atom.
For lactic acid, $C_3H_6O_3$:
$$\gamma=\frac{4(3)+1(6)-2(3)}{3}=\frac{12+6-6}{3}=\frac{12}{3}=\mathbf{4}.$$
Official GATE 2022 answer key: https://gate2026.iitg.ac.in/doc/download/Answer_keys2022/bt_2022.pdf