A brown substance 'X' on heating in air forms a substance 'Y' when hydrogen gas is passed over heated 'Y', it again changes back into 'X'

Gas evolved when NH_3 is passed over heated PbO is-

What is the change in internal energy of a substance when it is heated?

What wll happen when NH_3 is passed over heated cupric oxide. Give balanced equation.

Write, with balanced chemical equation, what happens when nitrogen gas is passed over calcium carbide heated at 1100^@C .

What happens when a ferromagnetic substance is heated at very high temperature?

Assertion : On heating ferrimagnetic or ferromagnetic substance , they become paramagnetic Reason :The electrons change their spin on heating

When dilute HCI is added to a white substance (A), a colourless gas (B) is evolved. When the gas (B) is passed through clear lime water, a white precipitate ( C) is obtained. The precipitate dissolves when excess of the gas (B) is passed through the lime water. The residue obtained on heating the solid substance (A) is yellow when hot but white when cold. When the gas (B) is passed through red hot charcoal, another gas (D) is obtained. The gas (D) gets absorbed in arnmoniacal cuprous chloride solution . Identify (A), (B), (C) and (D) and give the relevant reactions.

Assertion : On heating ferromagnetic or ferromagnetic substance , they become paramagnetic Reason :The electrons change their spin on heating

Write with balanced equation what happens when. : Nitric acid vapour is passed over heated copper metal.

Sweet smelling organic compound Is slowly oxidized by air in presence of light to a highly poisonous gas. On heating with silver powder, it forms a gaseous substance B, which is also produced by the action of calcium carbide on water. Identify A and B and write the chemical equations of the reactions involved.