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’. (i) Name the substance ‘X’ and ‘Y’. (ii) Name the type of chemical reaction occurring during both the changes. (iii) Write the chemical equations of the reactions.

(i) Name the substances ‘X’ and ‘Y’:

– Substance ‘X’: The brown substance is likely Copper(II) oxide (CuO).
– Substance ‘Y’: When heated in air, CuO forms Copper(I) oxide (Cu2O), which is typically a red or brownish substance.

(ii) Name the type of chemical reaction occurring during both changes:

– The reaction that occurs when ‘X’ (CuO) is heated in air to form ‘Y’ (Cu2O) is called Reduction.
– The reaction that occurs when hydrogen is passed over ‘Y’ (Cu2O) to regenerate ‘X’ (CuO) is called Oxidation.

(iii) Write the chemical equations of the reactions:

1. Heating ‘X’ in air: 2CuO+O2→2Cu2O

2. Passing hydrogen over ‘Y’: Cu2O+H2→2Cu+H2O

Summary:

– Substance ‘X’ is Copper(II) oxide (CuO), and Substance ‘Y’ is Copper(I) oxide (Cu2O).

– The reactions involve Reduction and Oxidation processes.

– The chemical equations represent the transformations between these substances.

(i) X-Cu; Y-CuO.

(ii) When copper is heated in air, oxidation takes place. When hydrogen gas is passed over heated copper oxide, reduction takes place.

(iii) 2𝐶𝑢 + 𝑂₂  {\overset{∆}{\longrightarrow}}  2𝐶𝑢𝑂 (𝑂𝑥𝑖𝑑𝑎𝑡𝑖𝑜𝑛)

𝐶𝑢𝑂 + 𝐻₂  {\overset{∆}{\longrightarrow}}  𝐶𝑢 + 𝐻₂𝑂 (𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛)