Which of the following elements is responsible for oxidation of water to O₂ in biological processes?

The most durable metal plating on iron to protect against corrosion is

Which of the following may be considered to be an organometallic compound?

The transition elements have a general electronic configuration

Among the lanthanides the one obtained by synthetic method is

Which one of the following ionic species will impart colour to an aqueous solution?

Which one of the following elements shows maximum number of different oxidation states in its compounds?

Photographic plates and films have an essential ingredient of