A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.
(a) Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.
(b) Name the black substance formed and give its chemical formula.

A silver article generally in sunlight turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining. Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.

A silver article generally sunlight turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining. Name the black substance formed and give its chemical formula.

Silver articles turn black when kept in the open for longer time due to the formation of

Silver articles become black when kept in open for some time, whereas copper vessels lose their shiny brown surfaces and gain a green coat when kept in open. Name the substances present in air with which these metals react and write the name of the products formed.

A reddish brown coloured metal is used in electrical wires. When powdered and heated strongly in an open china dish, its colour turns black. When hydrogen gas is passed over this black substance, it regains its original colour. Based on the above information, answer the following question. (i) Name the metal and the black coloured substance formed. (ii) Write balanced chemical equations for both the reactions.

Will a leaf taken from a potted plant kept in a dark room for a few days turn blue black when tested for starch? Give reasons for your answer.