Which one of following statements is incorrect ?

Options

A. Metal iron is corroded readily in noist air
B. Argentite is an ore of silver
C. oxidation state of Cr in `K_(2)Cr_(2)O_(7)` is `+12`
D. Photographic plates and films have an essential ingredient of silver bromide.

Answer

C

Explanation

Oxidation state of Cr in `K_(2)Cr_(2)O_(7)` is `+6`. Argentic or silver glance `(Ag_(2)S)` is an ore of Ag. The photographic plate or film consists of a glass plate or thin strip of celluloid, which is coated with the thin layer of an emulsion of Ag Br dispersed in galatin.