"Which of the following catalyst is used at what temprature in hydrogenation of vegetable oils? \(\text{Oil }+ H_2 \longrightarrow \text{Vanaspati ghee}\)"

Nickle at 150 °C -200 °C

The correct answer is 1. nickel at 150 °C -200 °C.

Nickel is the most commonly used catalyst for the hydrogenation of vegetable oils. It is active at relatively low temperatures, making it ideal for this process. Nickel is also relatively inexpensive and non-toxic, making it a safe and sustainable option.

Zinc oxide, cupric chloride, and ferric oxide are not typically used as catalysts for the hydrogenation of vegetable oils. Zinc oxide is not active at low temperatures, cupric chloride is toxic, and ferric oxide is not very active.

Therefore, nickel is the catalyst that is used at 150 °C -200 °C in the hydrogenation of vegetable oils.