Why is finely divided nickel used in hydrogenation of oil?

H_2S is used as hydrogen donor in

Name two catalysts used in hydrogenation of vegetable oils

State whether the following statements are true or false : Sodium hydroxide is used in the preparation of soap from fats and oils.

Why are microwaves used in radar?

Why are leeches used in Ayurveda.

Which of the following is NOT used in hydrogen-oxygen fuel cell ?

Why diatoms are used in filtration and polishing?

Why is it useful to define radius of gyration (K)?

Explain why finely divided substance is more effective as an adsorbent.

Give scientific reasons : The hydrogenation of vegetable oil in the presence of nickel catalyst forms vanaspati ghee.